CLIMATE CHANGE 2023

Synthesis Report

A Report of the Intergovernmental Panel on Climate Change

CLIMATE CHANGE 2023

Synthesis Report

Hoesung Lee (Chair), Katherine Calvin (USA), Dipak Dasgupta (India/USA), Gerhard Krinner (France/Germany), Aditi Mukherji

(India), Peter Thorne (Ireland/United Kingdom),Christopher Trisos (South Africa), José Romero (Switzerland), Paulina Aldunce

(Chile), Ko Barrett (USA), Gabriel Blanco (Argentina), William W. L. Cheung (Canada), Sarah L. Connors (France/United Kingdom),

Fatima Denton (The Gambia), Aïda Diongue-Niang (Senegal), David Dodman (Jamaica/United Kingdom/Netherlands), Matthias

Garschagen (Germany), Oliver Geden (Germany), Bronwyn Hayward (New Zealand), Christopher Jones (United Kingdom), Frank

Jotzo (Australia), Thelma Krug (Brazil), Rodel Lasco (Philippines), June-Yi Lee (Republic of Korea), Valérie Masson-Delmotte

(France), Malte Meinshausen (Australia/Germany), Katja Mintenbeck (Germany), Abdalah Mokssit (Morocco), Friederike E. L. Otto

(United Kingdom/Germany), Minal Pathak (India), Anna Pirani (Italy), Elvira Poloczanska (United Kingdom/Australia), Hans-Otto

Pörtner (Germany), Aromar Revi (India), Debra C. Roberts (South Africa), Joyashree Roy (India/Thailand), Alex C. Ruane (USA), Jim

Skea (United Kingdom), Priyadarshi R. Shukla (India), Raphael Slade (United Kingdom), Aimée Slangen (The Netherlands), Youba

Sokona (Mali), Anna A. Sörensson (Argentina), Melinda Tignor (USA/Germany), Detlef van Vuuren (The Netherlands), Yi-Ming Wei

(China), Harald Winkler (South Africa), Panmao Zhai (China), Zinta Zommers (Latvia)

Referencing this report:

IPCC, 2023: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report

of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland,

184 pp., doi: 10.59327/IPCC/AR6-9789291691647. 

Core Writing Team

Edited by

Hoesung Lee

Chairman

IPCC

José Romero

Head, Technical Support Unit

IPCC

The Core Writing Team

Synthesis Report

IPCC

José Romero (Switzerland), Jinmi Kim (Republic of Korea), Erik F. Haites (Canada), Yonghun Jung (Republic of Korea), Robert

Stavins (USA), Arlene Birt (USA), Meeyoung Ha (Republic of Korea), Dan Jezreel A. Orendain (Philippines), Lance Ignon (USA),

Semin Park (Republic of Korea), Youngin Park (Republic of Korea)

Technical Support Unit for the Synthesis Report

THE INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE

ISBN 978-92-9169-164-7

This publication is identical to the report that was approved (Summary for Policymakers) and adopted (longer report) at the 58th

session of the Intergovernmental Panel on Climate Change (IPCC) on 19 March 2023 in Interlaken, Switzerland, but with the

inclusion of copy-edits.

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Geneva 2, Switzerland E-mail: IPCC-Sec@wmo.int www.ipcc.ch

Paola Arias (Colombia), Mercedes Bustamante (Brazil), Ismail Elgizouli (Sudan), Gregory Flato (Canada), Mark Howden (Australia),

Carlos Méndez (Venezuela), Joy Jacqueline Pereira (Malaysia), Ramón Pichs-Madruga (Cuba), Steven K Rose (USA), Yamina Saheb

(Algeria/France), Roberto Sánchez Rodríguez (Mexico), Diana Ürge-Vorsatz (Hungary), Cunde Xiao (China), Noureddine Yassaa (Algeria)

Andrés Alegría (Germany/Honduras), Kyle Armour (USA), Birgit Bednar-Friedl (Austria), Kornelis Blok (The Netherlands), Guéladio

Cissé (Switzerland/Mauritania/France), Frank Dentener (EU/Netherlands), Siri Eriksen (Norway), Erich Fischer (Switzerland),

Gregory Garner (USA), Céline Guivarch (France), Marjolijn Haasnoot (The Netherlands), Gerrit Hansen (Germany), Mathias

Hauser (Switzerland), Ed Hawkins (UK), Tim Hermans (The Netherlands), Robert Kopp (USA), Noëmie Leprince-Ringuet (France),

Jared Lewis (Australia/New Zealand), Debora Ley (Mexico/Guatemala), Chloé Ludden (Germany/France), Leila Niamir (Iran/The

Netherlands/Austria), Zebedee Nicholls (Australia), Shreya Some (India/Thailand), Sophie Szopa (France), Blair Trewin (Australia),

Kaj-Ivar van der Wijst (The Netherlands), Gundula Winter (The Netherlands/Germany), Maximilian Witting (Germany)

Hoesung Lee (Chair, IPCC), Amjad Abdulla (Maldives), Edvin Aldrian (Indonesia), Ko Barrett (United States of America), Eduardo

Calvo (Peru), Carlo Carraro (Italy), Diriba Korecha Dadi (Ethiopia), Fatima Driouech (Morocco), Andreas Fischlin (Switzerland),

Jan Fuglestvedt (Norway), Thelma Krug (Brazil), Nagmeldin G.E. Mahmoud (Sudan), Valérie Masson-Delmotte (France), Carlos

Méndez (Venezuela), Joy Jacqueline Pereira (Malaysia), Ramón Pichs-Madruga (Cuba), Hans-Otto Pörtner (Germany), Andy

Reisinger (New Zealand), Debra C. Roberts (South Africa), Sergey Semenov (Russian Federation), Priyadarshi Shukla (India),

Jim Skea (United Kingdom), Youba Sokona (Mali), Kiyoto Tanabe (Japan), Muhammad Irfan Tariq (Pakistan), Diana Ürge-Vorsatz

(Hungary), Carolina Vera (Argentina), Pius Yanda (United Republic of Tanzania), Noureddine Yassaa (Algeria), Taha M. Zatari

(Saudi Arabia), Panmao Zhai (China)

Review Editors

Contributing Authors

Scientiﬁc Steering Committee

Arlene Birt (USA), Meeyoung Ha (Republic of Korea)

Visual Conception and Information Design

“Fog opening the dawn” by Chung Jin Sil

The Weather and Climate Photography & Video Contest 2021, Korea Meteorological Administration

http://www.kma.go.kr/kma © KMA

Photo Reference

Cover: Designed by Meeyoung Ha, IPCC SYR TSU

Jean-Charles Hourcade (France), Francis X. Johnson (Thailand/Sweden), Shonali Pachauri (Austria/India), Nicholas P. Simpson

(South Africa/Zimbabwe), Chandni Singh (India), Adelle Thomas (Bahamas), Edmond Totin (Benin)

Extended Writing Team

iii

Foreword and Preface

Foreword

This Synthesis Report (SYR) concludes the Sixth Assessment Report

(AR6) of the Intergovernmental Panel on Climate Change (IPCC).

The SYR synthesizes and integrates materials contained within the

three Working Groups Assessment Reports and the Special Reports

contributing to the AR6. It addresses a broad range of policy-relevant

but policy-neutral questions approved by the Panel.

The SYR is the synthesis of the most comprehensive assessment of

climate change undertaken thus far by the IPCC: Climate Change 2021:

The Physical Science Basis; Climate Change 2022: Impacts, Adaptation

and Vulnerability; and Climate Change 2022: Mitigation of Climate

Change. The SYR also draws on the ﬁndings of three Special Reports

completed as part of the Sixth Assessment – Global Warming of 1.5°C

(2018): an IPCC Special Report on the impacts of global warming of

1.5°C above pre-industrial levels and related global greenhouse gas

emission pathways, in the context of strengthening the global response

to the threat of climate change, sustainable development, and efforts

to eradicate poverty (SR1.5); Climate Change and Land (2019): an IPCC

Special Report on climate change, desertiﬁcation, land degradation,

sustainable land management, food security, and greenhouse gas

ﬂuxes in terrestrial ecosystems (SRCCL); and The Ocean and Cryosphere

in a Changing Climate (2019) (SROCC).

The AR6 SYR conﬁrms that unsustainable and unequal energy and land use

as well as more than a century of burning fossil fuels have unequivocally

caused global warming, with global surface temperature reaching 1.1°C

above 1850–1900 in 2011–2020. This has led to widespread adverse

impacts and related losses and damages to nature and people. The

nationally determined contributions (NDCs) committed by 2030 show the

temperature will increase by 1.5°C in the ﬁrst half of the 2030s, and will

make it very difﬁcult to control temperature increase by 2.0°C towards

the end of 21st century. Every increment of global warming will intensify

multiple and concurrent hazards in all regions of the world.

The report points out that limiting human-caused global warming

requires net zero CO

emissions. Deep, rapid, and sustained mitigation

and accelerated implementation of adaptation actions in this decade

would reduce projected losses and damages for humans and ecosystems

and deliver many co-beneﬁts, especially for air quality and health.

Delayed mitigation and adaptation action would lock-in high-emissions

infrastructure, raise risks of stranded assets and cost-escalation, reduce

feasibility, and increase losses and damages. Near-term actions involve

high up-front investments and potentially disruptive changes that can

be lessened by a range of enabling policies.

As an intergovernmental body jointly established in 1988 by

the World Meteorological Organization (WMO) and the United

Nations Environment Programme (UNEP), the IPCC has provided

policymakers with the most authoritative and objective scientific

and technical assessments in this field. Beginning in 1990, this

series of IPCC Assessment Reports, Special Reports, Technical Papers,

Methodology Reports, and other products have become standard

works of reference.

The SYR was made possible thanks to the voluntary work, dedication

and commitment of thousands of experts and scientists from around

the globe, representing a range of views and disciplines. We would like

to express our deep gratitude to all the members of the Core Writing

Team of the SYR, members of the Extended Writing Team, Contributing

Authors, and the Review Editors, all of whom enthusiastically took on

the huge challenge of producing an outstanding SYR on top of the other

tasks they had already committed to during the AR6 cycle. We would

also like to thank the staff of the Technical Support Unit of the SYR and

the IPCC Secretariat for their dedication in organizing the production of

this IPCC report.

We also wish to acknowledge and thank the governments of the IPCC

member countries for their support of scientists in developing this

report, and for their contributions to the IPCC Trust Fund to provide the

essentials for participation of experts from developing countries and

countries with economies in transition. We would like to express our

appreciation to the government of Singapore for hosting the Scoping

Meeting of the SYR, to the government of Ireland for hosting the third

Core Writing Team meeting of the SYR, and to the government of

Switzerland for hosting the 58th Session of the IPCC where the SYR

was approved. The generous ﬁnancial support from the government of

the Republic of Korea enabled the smooth operation of the Technical

Support Unit of the SYR. This is gratefully acknowledged.

We would particularly like to express our thanks to the IPCC Chair, the

IPCC Vice-Chairs and the Co-Chairs for their dedicated work throughout

the production of this report.

Petteri Taalas

Secretary-General of the World Meteorological Organization

Inger Andersen

Under-Secretary-General of the United Nations and Executive Director

of the UN Environment Programme

Forward

vii

This Synthesis Report (SYR) constitutes the final product of the

Sixth Assessment Report (AR6) of the Intergovernmental Panel on

Climate Change (IPCC). It summarizes the state of knowledge of

climate change, its widespread impacts and risks, and climate change

mitigation and adaptation, based on the peer-reviewed scientiﬁc,

technical, and socio-economic literature since the publication of the

IPCC’s Fifth Assessment Report (AR5) in 2014.

This SYR distills, synthesizes, and integrates the key findings of the

three Working Group contributions – Climate Change 2021: The

Physical Science Basis; Climate Change 2022: Impacts, Adaptation and

Vulnerability; and Climate Change 2022: Mitigation of Climate Change.

The SYR also draws on the ﬁndings of three Special Reports completed

as part of the Sixth Assessment – Global Warming of 1.5°C (2018):

an IPCC Special Report on the impacts of global warming of 1.5°C

above pre-industrial levels and related global greenhouse gas emission

pathways, in the context of strengthening the global response to the

threat of climate change, sustainable development, and efforts to

eradicate poverty (SR1.5); Climate Change and Land (2019): an IPCC

Special Report on climate change, desertiﬁcation, land degradation,

sustainable land management, food security, and greenhouse gas ﬂuxes

in terrestrial ecosystems (SRCCL); and The Ocean and Cryosphere in a

Changing Climate (2019) (SROCC). The SYR, therefore, is a comprehensive,

timely compilation of assessments of the most recent scientiﬁc, technical,

and socio-economic literature dealing with climate change.

Scope of the report

The SYR is a self-contained synthesis of the most policy-relevant

material drawn from the scientiﬁc, technical, and socio-economic

literature assessed during the Sixth Assessment. This report integrates

the main ﬁndings of the AR6 Working Group reports and the three

AR6 Special Reports. It recognizes the interdependence of climate,

ecosystems and biodiversity, and human societies; the value of

diverse forms of knowledge; and the close linkages between climate

adaptation, mitigation, ecosystem health, human well-being, and

sustainable development. Building on multiple analytical frameworks,

including those from the physical and social sciences, this report

identiﬁes opportunities for transformative action which are effective,

feasible, just and equitable systems transitions, and climate resilient

development pathways. Different regional classiﬁcation schemes are

used for physical, social and economic aspects, reﬂecting the underlying

literature.

The Synthesis Report emphasizes near-term risks and options for

addressing them to give policymakers a sense of the urgency required

to address global climate change. The report also provides important

insights about how climate risks interact with not only one another

but non-climate-related risks. It describes the interaction between

mitigation and adaptation and how this combination can better

confront the climate challenge as well as produce valuable co-beneﬁts. It

highlights the strong connection between equity and climate action and

why more equitable solutions are vital to addressing climate change. It

also emphasizes how growing urbanization provides an opportunity for

ambitious climate action to advance climate resilient development and

sustainable development for all. And it underscores how restoring and

protecting land and ocean ecosystems can bring multiple beneﬁts to

biodiversity and other societal goals, just as a failure to do so presents

a major risk to ensuring a healthy planet.

Structure

The SYR comprises a Summary for Policymakers (SPM) and a longer report

from which the SPM is derived, as well as annexes.

To facilitate access to the ﬁndings of the SYR for a wide readership, each

part of the SPM carries highlighted headline statements. Taken together,

these 18 headline statements provide an overarching summary in

simple, non-technical language for easy assimilation by readers from

different walks of life.

The SPM follows a structure and sequence like that in the longer report,

but some issues covered in more than one section of the longer report

are summarized in a single location in the SPM. Each paragraph of the

SPM contains references to the supporting text in the longer report.

In turn, the longer report contains extensive references to relevant

portions of the Working Group Reports or Special Reports mentioned

above.

The longer report is structured around three topic headings as

mandated by the Panel. A brief Introduction (Section1) is followed by

three sections.

Section 2, ‘Current Status and Trends’, opens with the assessment of

observational evidence for our changing climate, historical and current

drivers of human-induced climate change, and its impacts. It assesses the

current implementation of adaptation and mitigation response options.

Section 3, ‘Long-Term Climate and Development Futures’, provides an

assessment of climate change to 2100 and beyond in a broad range of

socio-economic futures. It considers long-term impacts, risks and costs

in adaptation and mitigation pathways in the context of sustainable

development. Section 4, ‘Near-Term Responses in a Changing Climate’,

assesses opportunities for scaling up effective action in the period to

2040, in the context of climate pledges, and commitments, and the

pursuit of sustainable development.

Annexes containing a glossary of terms used, list of acronyms, authors,

Review Editors, the SYR Scientiﬁc Steering Committee, and Expert

Reviewers complete the report.

Preface

viii

Process

The SYR was prepared in accordance with the procedures of the IPCC.

A scoping meeting to develop a detailed outline of the AR6 Synthesis

Report was held in Singapore from 21 to 23 October 2019 and the

outline produced in that meeting was approved by the Panel at the 52nd

IPCC Session from 24 to 28 February 2020 in Paris, France.

In accordance with IPCC procedures, the IPCC Chair, in consultation

with the Co-Chairs of the Working Groups, nominated authors for the

Core Writing Team (CWT) of the SYR. A total of 30 CWT members and

9 Review Editors were selected and accepted by the IPCC Bureau at its

58th Session on 19 May 2020. In the process of developing the SYR,

7 Extended Writing Team (EWT) authors were selected by the CWT and

approved by the Chair and the IPCC Bureau, and 28 Contributing Authors

were selected by the CWT with the approval of the Chair. These

additional authors were to enhance and deepen the expertise required

for the preparation of the Report. The Chair established at the 58th

Session of the Bureau an SYR Scientiﬁc Steering Committee (SSC) with a

mandate to advise the development of the SYR. The SYR SSC comprised

the members of the IPCC Bureau, excluding those members who served

as Review Editors for the SYR.

Due to the covid pandemic, the ﬁrst two meetings of the CWT were held

virtually from 25 to 29 January 2021 and from 16 to 20 August 2021.

The First Order Draft (FOD) was released to experts and governments

for review on 10 January 2022 with comments due on 20 March 2022.

The CWT met in Dublin from 25 to 28 March 2022 to discuss how

best to revise the FOD to address the more than 10,000 comments

received. The Review Editors monitored the review process to

ensure that all comments received appropriate consideration.

The IPCC circulated a final draft of the Summary for Policymakers

and a longer report of the SYR to governments for review from

21 November 2022 to 15 January 2023 which resulted in over 6,000

comments. A ﬁnal SYR draft for approval incorporating the comments

from the ﬁnal government distribution was submitted to the IPCC

member governments on 8 March 2023.

The Panel at its 58th Session, held from 13 to 17 March 2023 in

Interlaken, Switzerland, approved the SPM line by line and adopted the

longer report section by section.

Acknowledgements

The SYR was made possible thanks to the hard work and commitment to

excellence shown by the Section Facilitators, members of CWT and EWT,

and Contributing Authors. Speciﬁc thanks are due to Section Facilitators

Kate Calvin, Dipak Dasgupta, Gerhard Krinner, Aditi Mukherji, Peter Thorne,

and Christopher Trisos whose work was essential in ensuring a high

standard of the longer report sections and the SPM.

We would like to express our appreciation to the IPCC member

governments, observer organizations, and expert reviewers for providing

constructive comments on the draft reports. We would like to thank

the Review Editors Paola Arias, Mercedes Bustamante, Ismail Elgizouli,

Gregory Flato, Mark Howden, Steven Rose, Yamina Saheb, Roberto Sánchez,

and Cunde Xiao for their work on the treatment of FOD comments, and

Gregory Flato, Carlos Méndez, Joy Jacqueline Pereira, Ramón Pichs-

Madruga, Diana Ürge-Vorsatz, and Noureddine Yassaa for their work

during the approval session, collaborating with author teams to ensure

consistency between the SPM and the underlying reports.

We are grateful to the members of the SSC for their thoughtful advice

and support for the SYR throughout the process: IPCC Vice-Chairs Ko

Barret, Thelma Krug, and Youba Sokona; Co-Chairs of Working

Groups (WG) and Task Force on National Greenhouse Gas Inventories

(TFI) Valérie Masson-Delmotte, Panmao Zhai, Hans-Otto Pörtner,

Debra Roberts, Priyadarshi R. Shukla, Jim Skea, Eduardo Calvo Buendía,

and Kiyoto Tanabe; WG Vice-Chairs Edvin Aldrian, Fatima Driouech,

Jan Fuglestvedt, Muhammad Tariq, Carolina Vera, Noureddine Yassaa,

Andreas Fischlin, Joy Jacqueline Pereira, Sergey Semenov, Pius Yanda,

Taha M, Zatari, Amjad Abdulla, Carlo Carraro, Diriba Korecha Dadi,

Nagmeldin G.E. Mahmoud, Ramón Pichs-Madruga, Andy Reisinger,

and Diana Ürge-Vorsatz. The IPCC Vice-Chairs and WG Co-Chairs served

also as members of the CWT and we are grateful for their contributions.

We wish to thank the IPCC Secretariat for their guidance and support

for the SYR in preparation, release and publication of the Report:

Deputy Secretary Emira Fida, Mudathir Abdallah, Jesbin Baidya,

Laura Biagioni, Oksana Ekzarkho, Judith Ewa, Joëlle Fernandez,

Emelie Larrode, Jennifer Lew Schneider, Andrej Mahecic, Nina Peeva,

Mxolisi Shongwe, Melissa Walsh, and Werani Zabula. Their support for

the successful SYR was truly outstanding throughout the entire process.

Our thanks go to José Romero, Head of the SYR Technical Support Unit

(SYR TSU) and Jinmi Kim, Director of Administration, and the members

of the SYR TSU, Arlene Birt, Meeyoung Ha, Erik Haites, Lance Ignon,

Yonghun Jung, Dan Jezreel Orendain, Robert Stavins, Semin Park, and

Youngin Park for their hard work to facilitate the development and

production of the SYR with deep commitment and dedication to ensure

an outstanding SYR. Our thanks also go to Woochong Um and his team

at the Asian Development Bank for facilitation of the SYR TSU operation.

We extend our appreciation of the enthusiasm, dedication, and

professional contributions of WG TSU members Sarah Connors,

Clotilde Péan, and Anna Pirani from WG I, Marlies Craig,

Katja Mintenbeck, Elvira Poloczanska, Melinda Tignor from WG II and

Roger Fradera, Minal Pathak, Raphael Slade, Shreya Some, and

Geninha Gabao Lisboa from WG III, working as a team with the SYR TSU,

which contributed to the successful outcome of the Session.

We are appreciative of the member governments of the IPCC who

graciously hosted the SYR scoping meeting, a CWT Meeting and

the 58th Session of the IPCC: Singapore, Ireland, and Switzerland,

respectively. We express our thanks to the IPCC member governments,

WMO, UNEP and the UNFCCC for their contributions to the Trust Fund

which supported various elements of expenditure. We wish to particularly

Preface

thank the Korea Meteorological Administration, Republic of Korea for its

generous ﬁnancial support of the SYR TSU. We acknowledge the support

of IPCC’s parent organizations, UNEP and WMO, and particularly WMO

for hosting the IPCC Secretariat. Finally, may we convey our deep

gratitude to the UNFCCC for their cooperation at various stages of this

enterprise and for the prominence they give to our work in several fora.

Hoesung Lee

Chairman of the IPCC

Abdalah Mokssit

Secretary of the IPCC

Preface

Foreword -------------------------------------------------------------------------------------------------------------------------- v

Preface ---------------------------------------------------------------------------------------------------------------------------- vii

Summary for Policymakers ------------------------------------------------------------------------------------------- 1

Introduction -------------------------------------------------------------------------------------------------------------- 3

A. Current Status and Trends ----------------------------------------------------------------------------------------- 4

Box SPM.1 | Scenarios and pathways ------------------------------------------------------------------------------- 9

B. Future Climate Change, Risks, and Long-Term Responses ------------------------------------------------- 12

C. Responses in the Near Term ------------------------------------------------------------------------------------- 24

Climate Change 2023 ------------------------------------------------------------------------------------------------- 35

Section 1: Introduction ----------------------------------------------------------------------------------------------- 38

Section 2: Current Status and Trends ----------------------------------------------------------------------------- 41

2.1 Observed Changes, Impacts and Attribution ----------------------------------------------------------------42

2.1.1 Observed Warming and its Causes ---------------------------------------------------------------------- 42

2.1.2 Observed Climate System Changes and Impacts to Date ------------------------------------------ 46

2.2 Responses Undertaken to Date -------------------------------------------------------------------------------- 52

2.2.1 Global Policy Setting --------------------------------------------------------------------------------------- 52

2.2.2 Mitigation Actions to Date -------------------------------------------------------------------------------- 53

2.2.3 Adaptation Actions to Date ------------------------------------------------------------------------------- 55

2.3 Current Mitigation and Adaptation Actions and Policies are not Sufﬁcient ------------------------- 57

2.3.1 The Gap Between Mitigation Policies, Pledges and Pathways that Limit Warming to

1.5°C or Below 2°C ---------------------------------------------------------------------------------------- 57

Cross-Section Box.1| Understanding Net Zero CO

and Net Zero GHG Emissions ---------------------- 80

2.3.2 Adaptation Gaps and Barriers ---------------------------------------------------------------------------- 61

2.3.3 Lack of Finance as a Barrier to Climate Action ------------------------------------------------------- 63

Cross-Section Box.2 | Scenarios, Global Warming Levels, and Risks ----------------------------------------- 63

Contents

Front matter

SPM

Sections

xii

Section 3: Long-Term Climate and Development Futures---------------------------------------------------- 67

3.1 Long-Term Climate Change, Impacts and Related Risks ------------------------------------------------- 68

3.1.1 Long-term Climate Change ------------------------------------------------------------------------------- 68

3.1.2 Impacts and Related Risks -------------------------------------------------------------------------------- 71

3.1.3 The Likelihood and Risks of Abrupt and Irreversible Change -------------------------------------- 77

3.2 Long-term Adaptation Options and Limits ------------------------------------------------------------------ 78

3.3 Mitigation Pathways --------------------------------------------------------------------------------------------- 82

3.3.1 Remaining Carbon Budgets ------------------------------------------------------------------------------- 82

3.3.2 Net Zero Emissions: Timing and Implications --------------------------------------------------------- 85

3.3.3 Sectoral Contributions to Mitigation -------------------------------------------------------------------- 86

3.3.4 Overshoot Pathways: Increased Risks and Other Implications ------------------------------------- 87

3.4 Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development ----------------- 88

3.4.1 Synergies and trade-offs, costs and beneﬁts ---------------------------------------------------------- 88

3.4.2 Advancing Integrated Climate Action for Sustainable Development ----------------------------- 89

Section 4: Near-Term Responses in a Changing Climate ----------------------------------------------------- 91

4.1The Timing and Urgency of Climate Action ------------------------------------------------------------------ 92

4.2 Beneﬁts of Strengthening Near-Term Action --------------------------------------------------------------- 95

4.3 Near-Term Risks -------------------------------------------------------------------------------------------------- 97

4.4 Equity and Inclusion in Climate Change Action ---------------------------------------------------------- 101

4.5 Near-Term Mitigation and Adaptation Actions ---------------------------------------------------------- 102

4.5.1 Energy Systems -------------------------------------------------------------------------------------------- 104

4.5.2 Industry ----------------------------------------------------------------------------------------------------- 104

4.5.3 Cities, Settlements and Infrastructure ----------------------------------------------------------------- 105

4.5.4 Land, Ocean, Food, and Water -------------------------------------------------------------------------- 106

4.5.5 Health and Nutrition -------------------------------------------------------------------------------------- 106

4.5.6 Society, Livelihoods, and Economies ------------------------------------------------------------------ 107

4.6 Co-Beneﬁts of Adaptation and Mitigation for Sustainable Development Goals ------------------ 108

4.7 Governance and Policy for Near-Term Climate Change Action ---------------------------------------- 110

4.8 Strengthening the Response: Finance, International Cooperation and Technology --------------- 111

4.8.1 Finance for Mitigation and Adaptation Actions ----------------------------------------------------- 111

4.8.2 International Cooperation and Coordination -------------------------------------------------------- 112

4.8.3 Technology Innovation, Adoption, Diffusion and Transfer ----------------------------------------- 113

4.9 Integration of Near-Term Actions Across Sectors and Systems ---------------------------------------- 114

xiii

Annexes ---------------------------------------------------------------------------------------------------------------- 117

I. Glossary -------------------------------------------------------------------------------------------------------------------- 119

II. Acronyms, Chemical Symbols and Scientiﬁc Units ----------------------------------------------------------------- 131

III. Contributors --------------------------------------------------------------------------------------------------------------- 135

IV. Expert Reviewers --------------------------------------------------------------------------------------------------------- 143

V. Publications by the Intergovernmental Panel on Climate Change ---------------------------------------------- 161

Index -------------------------------------------------------------------------------------------------------------------- 163

Annexes

xiv

Sources cited in this Synthesis Report

References for material contained in this report are given in curly brackets {} at the end of each paragraph.

In the Summary for Policymakers, the references refer to the numbers of the sections, ﬁgures, tables and boxes in the underlying

Introduction and Topics of this Synthesis Report.

In the Introduction and Sections of the longer report, the references refer to the contributions of the Working Groups I, II and

III (WGI, WGII, WGIII) to the Sixth Assessment Report and other IPCC Reports (in italicized curly brackets), or to other sections

of the Synthesis Report itself (in round brackets).

The following abbreviations have been used:

SPM: Summary for Policymakers

TS: Technical Summary

ES: Executive Summary of a chapter

Numbers denote speciﬁc chapters and sections of a report.

Other IPCC reports cited in this Synthesis Report:

SR1.5: Global Warming of 1.5°C

SRCCL: Climate Change and Land

SROCC: The Ocean and Cryosphere in a Changing Climate

Climate Change 2023

Synthesis Report

Summary for Policymakers

IPCC, 2023: Summary for Policymakers. In: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to

the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)].

IPCC, Geneva, Switzerland, pp. 1-34, doi: 10.59327/IPCC/AR6-9789291691647.001

This Summary for Policymakers should be cited as:

Summary for Policymakers

Introduction

This Synthesis Report (SYR) of the IPCC Sixth Assessment Report (AR6) summarises the state of knowledge of climate change,

its widespread impacts and risks, and climate change mitigation and adaptation. It integrates the main ﬁndings of the Sixth

Assessment Report (AR6) based on contributions from the three Working Groups

, and the three Special Reports

. The summary

for Policymakers (SPM) is structured in three parts: SPM.A Current Status and Trends, SPM.B Future Climate Change, Risks, and

Long-Term Responses, and SPM.C Responses in the Near Term

This report recognizes the interdependence of climate, ecosystems and biodiversity, and human societies; the value of diverse

forms of knowledge; and the close linkages between climate change adaptation, mitigation, ecosystem health, human well-being

and sustainable development, and reﬂects the increasing diversity of actors involved in climate action.

Based on scientiﬁc understanding, key ﬁndings can be formulated as statements of fact or associated with an assessed level of

conﬁdence using the IPCC calibrated language

. 

The three Working Group contributions to AR6 are: AR6 Climate Change 2021: The Physical Science Basis; AR6 Climate Change 2022: Impacts, Adaptation

and Vulnerability; and AR6 Climate Change 2022: Mitigation of Climate Change. Their assessments cover scientiﬁc literature accepted for publication

respectively by 31 January 2021, 1 September 2021 and 11 October 2021.

The three Special Reports are: Global Warming of 1.5°C (2018): an IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial

levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable

development, and efforts to eradicate poverty (SR1.5); Climate Change and Land (2019): an IPCC Special Report on climate change, desertiﬁcation, land

degradation, sustainable land management, food security, and greenhouse gas ﬂuxes in terrestrial ecosystems (SRCCL); and The Ocean and Cryosphere in

a Changing Climate (2019) (SROCC). The Special Reports cover scientiﬁc literature accepted for publication respectively by 15 May 2018, 7 April 2019 and

15 May 2019.

In this report, the near term is deﬁned as the period until 2040. The long term is deﬁned as the period beyond 2040.

Each ﬁnding is grounded in an evaluation of underlying evidence and agreement. The IPCC calibrated language uses ﬁve qualiﬁers to express a level of

conﬁdence: very low, low, medium, high and very high, and typeset in italics, for example, medium conﬁdence. The following terms are used to indicate the

assessed likelihood of an outcome or a result: virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, more likely than not >50–100%,

about as likely as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%. Additional terms (extremely likely 95–100%; and

extremely unlikely 0–5%) are also used when appropriate. Assessed likelihood is typeset in italics, e.g., very likely. This is consistent with AR5 and the other

AR6 Reports.

Summary for Policymakers

A. Current Status and Trends

Observed Warming and its Causes

A.1 Human activities, principally through emissions of greenhouse gases, have unequivocally

caused global warming, with global surface temperature reaching 1.1°C above 1850–1900

in 2011–2020. Global greenhouse gas emissions have continued to increase, with unequal

historical and ongoing contributions arising from unsustainable energy use, land use and

land-use change, lifestyles and patterns of consumption and production across regions,

between and within countries, and among individuals (high conﬁdence). {2.1, Figure 2.1,

Figure 2.2}

A.1.1 Global surface temperature was 1.09 [0.95 to 1.20]°C

higher in 2011–2020 than 1850–1900

, with larger increases

over land (1.59 [1.34 to 1.83]°C) than over the ocean (0.88 [0.68 to 1.01]°C). Global surface temperature in the ﬁrst two

decades of the 21

century (2001–2020) was 0.99 [0.84 to 1.10]°C higher than 1850–1900. Global surface temperature

has increased faster since 1970 than in any other 50-year period over at least the last 2000 years (high conﬁdence).

{2.1.1, Figure 2.1}

A.1.2 The likely range of total human-caused global surface temperature increase from 1850–1900 to 2010–2019

is 0.8°C to

1.3°C, with a best estimate of 1.07°C. Over this period, it is likely that well-mixed greenhouse gases (GHGs) contributed

a warming of 1.0°C to 2.0°C

, and other human drivers (principally aerosols) contributed a cooling of 0.0°C to 0.8°C,

natural (solar and volcanic) drivers changed global surface temperature by –0.1°C to +0.1°C, and internal variability

changed it by –0.2°C to +0.2°C. {2.1.1, Figure 2.1}

A.1.3 Observed increases in well-mixed GHG concentrations since around 1750 are unequivocally caused by GHG emissions

from human activities over this period. Historical cumulative net CO

emissions from 1850 to 2019 were 2400 ± 240 GtCO

of which more than half (58%) occurred between 1850 and 1989, and about 42% occurred between 1990 and 2019 (high

conﬁdence). In 2019, atmospheric CO

concentrations (410 parts per million) were higher than at any time in at least 2

million years (high conﬁdence), and concentrations of methane (1866 parts per billion) and nitrous oxide (332 parts per

billion) were higher than at any time in at least 800,000 years (very high conﬁdence). {2.1.1, Figure 2.1}

A.1.4 Global net anthropogenic GHG emissions have been estimated to be 59 ± 6.6 GtCO

-eq

in 2019, about 12% (6.5 GtCO

-eq)

higher than in 2010 and 54% (21 GtCO

-eq) higher than in 1990, with the largest share and growth in gross GHG emissions

occurring in CO

from fossil fuels combustion and industrial processes (CO

-FFI) followed by methane, whereas the highest

relative growth occurred in ﬂuorinated gases (F-gases), starting from low levels in 1990. Average annual GHG emissions

during 2010–2019 were higher than in any previous decade on record, while the rate of growth between 2010 and

2019 (1.3% yr

-1

) was lower than that between 2000 and 2009 (2.1% yr

-1

). In 2019, approximately 79% of global GHG

Ranges given throughout the SPM represent very likely ranges (5–95% range) unless otherwise stated.

The estimated increase in global surface temperature since AR5 is principally due to further warming since 2003–2012 (0.19 [0.16 to 0.22]°C). Additionally,

methodological advances and new datasets have provided a more complete spatial representation of changes in surface temperature, including in the

Arctic. These and other improvements have also increased the estimate of global surface temperature change by approximately 0.1°C, but this increase

does not represent additional physical warming since AR5.

The period distinction with A.1.1 arises because the attribution studies consider this slightly earlier period. The observed warming to 2010–2019

is 1.06 [0.88 to 1.21]°C.

Contributions from emissions to the 2010–2019 warming relative to 1850–1900 assessed from radiative forcing studies are: CO

0.8 [0.5 to 1.2] °C;

methane 0.5 [0.3 to 0.8]°C; nitrous oxide 0.1 [0.0 to 0.2]°C and ﬂuorinated gases 0.1 [0.0 to 0.2]°C. {2.1.1}

GHG emission metrics are used to express emissions of different greenhouse gases in a common unit. Aggregated GHG emissions in this report are stated in CO

equivalents (CO

-eq) using the Global Warming Potential with a time horizon of 100 years (GWP100) with values based on the contribution of Working Group I to

the AR6. The AR6 WGI and WGIII reports contain updated emission metric values, evaluations of different metrics with regard to mitigation objectives, and

assess new approaches to aggregating gases. The choice of metric depends on the purpose of the analysis and all GHG emission metrics have limitations

and uncertainties, given that they simplify the complexity of the physical climate system and its response to past and future GHG emissions. {2.1.1}

Summary for Policymakers

emissions came from the sectors of energy, industry, transport, and buildings together and 22%

from agriculture,

forestry and other land use (AFOLU). Emissions reductions in CO

-FFI due to improvements in energy intensity of GDP

and carbon intensity of energy, have been less than emissions increases from rising global activity levels in industry,

energy supply, transport, agriculture and buildings. (high conﬁdence) {2.1.1}

A.1.5 Historical contributions of CO

emissions vary substantially across regions in terms of total magnitude, but also in

terms of contributions to CO

-FFI and net CO

emissions from land use, land-use change and forestry (CO

-LULUCF).

In 2019, around 35% of the global population live in countries emitting more than 9 tCO

-eq per capita

(excluding

-LULUCF) while 41% live in countries emitting less than 3 tCO

-eq per capita; of the latter a substantial share lacks

access to modern energy services. Least Developed Countries (LDCs) and Small Island Developing States (SIDS) have

much lower per capita emissions (1.7 tCO

-eq and 4.6 tCO

-eq, respectively) than the global average (6.9 tCO

-eq),

excluding CO

-LULUCF. The 10% of households with the highest per capita emissions contribute 34–45% of global

consumption-based household GHG emissions, while the bottom 50% contribute 13–15%. (high conﬁdence) {2.1.1,

Figure 2.2}

Observed Changes and Impacts

A.2 Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have

occurred. Human-caused climate change is already affecting many weather and climate

extremes in every region across the globe. This has led to widespread adverse impacts and

related losses and damages to nature and people (high conﬁdence). Vulnerable communities

who have historically contributed the least to current climate change are disproportionately

affected (high conﬁdence). {2.1, Table 2.1, Figure 2.2, Figure 2.3} (Figure SPM.1)

A.2.1 It is unequivocal that human inﬂuence has warmed the atmosphere, ocean and land. Global mean sea level increased by

0.20 [0.15 to 0.25] m between 1901 and 2018. The average rate of sea level rise was 1.3 [0.6 to 2.1] mm yr

-1

between 1901

and 1971, increasing to 1.9 [0.8 to 2.9] mm yr

-1

between 1971 and 2006, and further increasing to 3.7 [3.2 to 4.2] mm yr

-1

between 2006 and 2018 (high conﬁdence). Human inﬂuence was very likely the main driver of these increases since at

least 1971. Evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical

cyclones, and, in particular, their attribution to human inﬂuence, has further strengthened since AR5. Human inﬂuence

has likely increased the chance of compound extreme events since the 1950s, including increases in the frequency of

concurrent heatwaves and droughts (high conﬁdence). {2.1.2, Table 2.1, Figure 2.3, Figure 3.4} (Figure SPM.1)

A.2.2 Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change. Human and

ecosystem vulnerability are interdependent. Regions and people with considerable development constraints have high

vulnerability to climatic hazards. Increasing weather and climate extreme events have exposed millions of people

to acute food insecurity

and reduced water security, with the largest adverse impacts observed in many locations

and/or communities in Africa, Asia, Central and South America, LDCs, Small Islands and the Arctic, and globally for

Indigenous Peoples, small-scale food producers and low-income households. Between 2010 and 2020, human mortality

from ﬂoods, droughts and storms was 15 times higher in highly vulnerable regions, compared to regions with very low

vulnerability. (high conﬁdence) {2.1.2, 4.4} (Figure SPM.1)

A.2.3 Climate change has caused substantial damages, and increasingly irreversible losses, in terrestrial, freshwater,

cryospheric, and coastal and open ocean ecosystems (high conﬁdence). Hundreds of local losses of species have been

driven by increases in the magnitude of heat extremes (high conﬁdence) with mass mortality events recorded on

land and in the ocean (very high conﬁdence). Impacts on some ecosystems are approaching irreversibility such as

the impacts of hydrological changes resulting from the retreat of glaciers, or the changes in some mountain (medium

conﬁdence) and Arctic ecosystems driven by permafrost thaw (high conﬁdence). {2.1.2, Figure 2.3} (Figure SPM.1)

GHG emission levels are rounded to two signiﬁcant digits; as a consequence, small differences in sums due to rounding may occur. {2.1.1}

Territorial emissions.

Acute food insecurity can occur at any time with a severity that threatens lives, livelihoods or both, regardless of the causes, context or duration, as a result

of shocks risking determinants of food security and nutrition, and is used to assess the need for humanitarian action. {2.1}

Summary for Policymakers

A.2.4 Climate change has reduced food security and affected water security, hindering efforts to meet Sustainable

Development Goals (high conﬁdence). Although overall agricultural productivity has increased, climate change has

slowed this growth over the past 50 years globally (medium conﬁdence), with related negative impacts mainly in mid-

and low latitude regions but positive impacts in some high latitude regions (high conﬁdence). Ocean warming and

ocean acidiﬁcation have adversely affected food production from ﬁsheries and shellﬁsh aquaculture in some oceanic

regions (high conﬁdence). Roughly half of the world’s population currently experience severe water scarcity for at least

part of the year due to a combination of climatic and non-climatic drivers (medium conﬁdence). {2.1.2, Figure 2.3}

(Figure SPM.1)

A.2.5 In all regions increases in extreme heat events have resulted in human mortality and morbidity (very high conﬁdence).

The occurrence of climate-related food-borne and water-borne diseases (very high conﬁdence) and the incidence

of vector-borne diseases (high conﬁdence) have increased. In assessed regions, some mental health challenges are

associated with increasing temperatures (high conﬁdence), trauma from extreme events (very high conﬁdence), and

loss of livelihoods and culture (high conﬁdence). Climate and weather extremes are increasingly driving displacement

in Africa, Asia, North America (high conﬁdence), and Central and South America (medium conﬁdence), with small island

states in the Caribbean and South Paciﬁc being disproportionately affected relative to their small population size (high

conﬁdence). {2.1.2, Figure 2.3} (Figure SPM.1)

A.2.6 Climate change has caused widespread adverse impacts and related losses and damages

to nature and people that are

unequally distributed across systems, regions and sectors. Economic damages from climate change have been detected

in climate-exposed sectors, such as agriculture, forestry, ﬁshery, energy, and tourism. Individual livelihoods have been

affected through, for example, destruction of homes and infrastructure, and loss of property and income, human health

and food security, with adverse effects on gender and social equity. (high conﬁdence) {2.1.2} (Figure SPM.1)

A.2.7 In urban areas, observed climate change has caused adverse impacts on human health, livelihoods and key infrastructure.

Hot extremes have intensiﬁed in cities. Urban infrastructure, including transportation, water, sanitation and energy

systems have been compromised by extreme and slow-onset events

, with resulting economic losses, disruptions of

services and negative impacts to well-being. Observed adverse impacts are concentrated amongst economically and

socially marginalised urban residents. (high conﬁdence) {2.1.2}

In this report, the term ‘losses and damages’ refers to adverse observed impacts and/or projected risks and can be economic and/or non-economic (see

Annex I: Glossary).

Slow-onset events are described among the climatic-impact drivers of the AR6 WGI and refer to the risks and impacts associated with e.g., increasing

temperature means, desertiﬁcation, decreasing precipitation, loss of biodiversity, land and forest degradation, glacial retreat and related impacts, ocean

acidiﬁcation, sea level rise and salinization. {2.1.2}

Summary for Policymakers

Figure SPM.1: (a) Climate change has already caused widespread impacts and related losses and damages on human systems and altered terrestrial,

freshwater and ocean ecosystems worldwide. Physical water availability includes balance of water available from various sources including ground water, water

quality and demand for water. Global mental health and displacement assessments reﬂect only assessed regions. Conﬁdence levels reﬂect the assessment of

attribution of the observed impact to climate change. (b) Observed impacts are connected to physical climate changes including many that have been attributed

to human inﬂuence such as the selected climatic impact-drivers shown. Conﬁdence and likelihood levels reﬂect the assessment of attribution of the observed

climatic impact-driver to human inﬂuence. (c) Observed (1900–2020) and projected (2021–2100) changes in global surface temperature (relative to 1850-1900),

which are linked to changes in climate conditions and impacts, illustrate how the climate has already changed and will change along the lifespan of three

Adverse impacts from human-caused

climate change will continue to intensify

Terrestrial

ecosystems

Freshwater

ecosystems

Ocean

ecosystems

a) Observed widespread and substantial impacts and

related losses and damages attributed to climate change

Conﬁdence in attribution

to climate change

High or very high conﬁdence

Medium conﬁdence

Low conﬁdence

Includes changes in ecosystem structure,

species ranges and seasonal timing

Biodiversity and ecosystems

Water availability and food production Health and well-being

Cities, settlements and infrastructure

Inland

ﬂooding and

associated

damages

Flood/storm

induced

damages in

coastal areas

Damages

to key

economic

sectors

Damages

to infra-

structure

Physical

water

availability

Agriculture/

crop

production

Fisheries

yields and

aquaculture

production

Animal and

livestock

health and

productivity

Infectious

diseases

DisplacementMental

health

Heat,

malnutrition

and harm

from wildﬁre

Observed increase in climate impacts

to human systems and ecosystems

assessed at global level

Adverse impacts

Adverse and positive impacts

Climate-driven changes observed,

no global assessment of impact direction

Key

1900 1940 1980 2060 2100

very high

high

very low

low

intermediate

2020

future experiences depend on

how we address climate change

2011-2020 was

around 1.1°C warmer

than 1850-1900

warming

continues

beyond

2100

70 years

old

in 2050

born

in 1980

born

in 2020

born

in 1950

70 years

old

in 2090

70 years

old

in 2020

Global temperature change above 1850-1900 levels

°C

0 0.5 1 1.5 2 2.5 3 43.5

c) The extent to which current and future generations will experience a

hotter and different world depends on choices now and in the near term

Future emissions

scenarios:

b) Impacts are driven by changes in multiple physical climate

conditions, which are increasingly attributed to human inﬂuence

Attribution of observed physical climate changes to human inﬂuence:

Virtually certain

Increase

in hot

extremes

Upper

ocean

acidiﬁcation

Likely

Increase

in heavy

precipitation

Very likely

Global sea

level rise

Glacier

retreat

Medium conﬁdence

Increase in

compound

ﬂooding

Increase in

agricultural

& ecological

drought

Increase

in ﬁre

weather

Summary for Policymakers

representative generations (born in 1950, 1980 and 2020). Future projections (2021–2100) of changes in global surface temperature are shown for very low

(SSP1-1.9), low (SSP1-2.6), intermediate (SSP2-4.5), high (SSP3-7.0) and very high (SSP5-8.5) GHG emissions scenarios. Changes in annual global surface

temperatures are presented as ‘climate stripes’, with future projections showing the human-caused long-term trends and continuing modulation by natural

variability (represented here using observed levels of past natural variability). Colours on the generational icons correspond to the global surface temperature

stripes for each year, with segments on future icons differentiating possible future experiences. {2.1, 2.1.2, Figure 2.1, Table 2.1, Figure 2.3, Cross-Section Box.2,

3.1, Figure 3.3, 4.1, 4.3} (Box SPM.1)

Current Progress in Adaptation and Gaps and Challenges

A.3 Adaptation planning and implementation has progressed across all sectors and regions,

with documented beneﬁts and varying effectiveness. Despite progress, adaptation gaps

exist, and will continue to grow at current rates of implementation. Hard and soft limits to

adaptation have been reached in some ecosystems and regions. Maladaptation is happening

in some sectors and regions. Current global ﬁnancial ﬂows for adaptation are insufﬁcient

for, and constrain implementation of, adaptation options, especially in developing countries

(high conﬁdence). {2.2, 2.3}

A.3.1 Progress in adaptation planning and implementation has been observed across all sectors and regions, generating

multiple beneﬁts (very high conﬁdence). Growing public and political awareness of climate impacts and risks has

resulted in at least 170 countries and many cities including adaptation in their climate policies and planning processes

(high conﬁdence). {2.2.3}

A.3.2 Effectiveness

of adaptation in reducing climate risks

is documented for speciﬁc contexts, sectors and regions (high

conﬁdence). Examples of effective adaptation options include: cultivar improvements, on-farm water management and

storage, soil moisture conservation, irrigation, agroforestry, community-based adaptation, farm and landscape level

diversiﬁcation in agriculture, sustainable land management approaches, use of agroecological principles and practices

and other approaches that work with natural processes (high conﬁdence). Ecosystem-based adaptation

approaches

such as urban greening, restoration of wetlands and upstream forest ecosystems have been effective in reducing

ﬂood risks and urban heat (high conﬁdence). Combinations of non-structural measures like early warning systems and

structural measures like levees have reduced loss of lives in case of inland ﬂooding (medium conﬁdence). Adaptation

options such as disaster risk management, early warning systems, climate services and social safety nets have broad

applicability across multiple sectors (high conﬁdence). {2.2.3}

A.3.3 Most observed adaptation responses are fragmented, incremental

, sector-speciﬁc and unequally distributed across

regions. Despite progress, adaptation gaps exist across sectors and regions, and will continue to grow under current

levels of implementation, with the largest adaptation gaps among lower income groups. (high conﬁdence) {2.3.2}

A.3.4 There is increased evidence of maladaptation in various sectors and regions. Maladaptation especially affects

marginalised and vulnerable groups adversely. (high conﬁdence) {2.3.2}

A.3.5 Soft limits to adaptation are currently being experienced by small-scale farmers and households along some low-

lying coastal areas (medium conﬁdence) resulting from ﬁnancial, governance, institutional and policy constraints

(high conﬁdence). Some tropical, coastal, polar and mountain ecosystems have reached hard adaptation limits (high

conﬁdence). Adaptation does not prevent all losses and damages, even with effective adaptation and before reaching

soft and hard limits (high conﬁdence). {2.3.2}

Effectiveness refers here to the extent to which an adaptation option is anticipated or observed to reduce climate-related risk. {2.2.3}

See Annex I: Glossary. {2.2.3}

Ecosystem-based Adaptation (EbA) is recognized internationally under the Convention on Biological Diversity (CBD14/5). A related concept is Nature-based

Solutions (NbS), see Annex I: Glossary.

Incremental adaptations to change in climate are understood as extensions of actions and behaviours that already reduce the losses or enhance the

beneﬁts of natural variations in extreme weather/climate events. {2.3.2}

Summary for Policymakers

A.3.6 Key barriers to adaptation are limited resources, lack of private sector and citizen engagement, insufﬁcient mobilization

of ﬁnance (including for research), low climate literacy, lack of political commitment, limited research and/or slow and

low uptake of adaptation science, and low sense of urgency. There are widening disparities between the estimated costs

of adaptation and the ﬁnance allocated to adaptation (high conﬁdence). Adaptation ﬁnance has come predominantly

from public sources, and a small proportion of global tracked climate ﬁnance was targeted to adaptation and an

overwhelming majority to mitigation (very high conﬁdence). Although global tracked climate ﬁnance has shown

an upward trend since AR5, current global ﬁnancial ﬂows for adaptation, including from public and private ﬁnance

sources, are insufﬁcient and constrain implementation of adaptation options, especially in developing countries (high

conﬁdence). Adverse climate impacts can reduce the availability of ﬁnancial resources by incurring losses and damages

and through impeding national economic growth, thereby further increasing ﬁnancial constraints for adaptation,

particularly for developing and least developed countries (medium conﬁdence). {2.3.2, 2.3.3}

Box SPM.1 The use of scenarios and modelled pathways in the AR6 Synthesis Report

Modelled scenarios and pathways

are used to explore future emissions, climate change, related impacts and risks, and

possible mitigation and adaptation strategies and are based on a range of assumptions, including socio-economic variables

and mitigation options. These are quantitative projections and are neither predictions nor forecasts. Global modelled emission

pathways, including those based on cost effective approaches contain regionally differentiated assumptions and outcomes,

and have to be assessed with the careful recognition of these assumptions. Most do not make explicit assumptions about

global equity, environmental justice or intra-regional income distribution. IPCC is neutral with regard to the assumptions

underlying the scenarios in the literature assessed in this report, which do not cover all possible futures.

{Cross-Section Box.2}

WGI assessed the climate response to ﬁve illustrative scenarios based on Shared Socio-economic Pathways (SSPs)

that

cover the range of possible future development of anthropogenic drivers of climate change found in the literature. High and

very high GHG emissions scenarios (SSP3-7.0 and SSP5-8.5

) have CO

emissions that roughly double from current levels

by 2100 and 2050, respectively. The intermediate GHG emissions scenario (SSP2-4.5) has CO

emissions remaining around

current levels until the middle of the century. The very low and low GHG emissions scenarios (SSP1-1.9 and SSP1-2.6) have CO

emissions declining to net zero around 2050 and 2070, respectively, followed by varying levels of net negative CO

emissions.

In addition, Representative Concentration Pathways (RCPs)

were used by WGI and WGII to assess regional climate changes,

impacts and risks. In WGIII, a large number of global modelled emissions pathways were assessed, of which 1202 pathways

were categorised based on their assessed global warming over the 21st century; categories range from pathways that limit

warming to 1.5°C with more than 50% likelihood (noted >50% in this report) with no or limited overshoot (C1) to pathways

that exceed 4°C (C8). {Cross-Section Box.2} (Box SPM.1, Table 1)

Global warming levels (GWLs) relative to 1850–1900 are used to integrate the assessment of climate change and related

impacts and risks since patterns of changes for many variables at a given GWL are common to all scenarios considered and

independent of timing when that level is reached. {Cross-Section Box.2}

In the literature, the terms pathways and scenarios are used interchangeably, with the former more frequently used in relation to climate goals. WGI

primarily used the term scenarios and WGIII mostly used the term modelled emission and mitigation pathways. The SYR primarily uses scenarios when

referring to WGI and modelled emission and mitigation pathways when referring to WGIII.

Around half of all modelled global emission pathways assume cost-effective approaches that rely on least-cost mitigation/abatement options globally. The

other half looks at existing policies and regionally and sectorally differentiated actions.

SSP-based scenarios are referred to as SSPx-y, where ‘SSPx’ refers to the Shared Socioeconomic Pathway describing the socioeconomic trends underlying the

scenarios, and ‘y’ refers to the level of radiative forcing (in watts per square metre, or W m

-2

) resulting from the scenario in the year 2100. {Cross-Section Box.2}

Very high emissions scenarios have become less likely but cannot be ruled out. Warming levels >4°C may result from very high emissions scenarios, but can

also occur from lower emission scenarios if climate sensitivity or carbon cycle feedbacks are higher than the best estimate. {3.1.1}

RCP-based scenarios are referred to as RCPy, where ‘y’ refers to the level of radiative forcing (in watts per square metre, or W m

-2

) resulting from the

scenario in the year 2100. The SSP scenarios cover a broader range of greenhouse gas and air pollutant futures than the RCPs. They are similar but not

identical, with differences in concentration trajectories. The overall effective radiative forcing tends to be higher for the SSPs compared to the RCPs with the

same label (medium conﬁdence). {Cross-Section Box.2}

Summary for Policymakers

Category

in WGIII

Category description

GHG emissions scenarios

(SSPx-y*) in WGI & WGII

RCPy** in WGI & WGII

limit warming to 1.5°C (>50%)

with no or limited overshoot***

Very low (SSP1-1.9)

Low (SSP1-2.6) RCP2.6

return warming to 1.5°C (>50%)

after a high overshoot***

C3 limit warming to 2°C (>67%)

C4 limit warming to 2°C (>50%)

C5 limit warming to 2.5°C (>50%)

C6 limit warming to 3°C (>50%)

Intermediate (SSP2-4.5) RCP 4.5

RCP 8.5

C7 limit warming to 4°C (>50%)

High (SSP3-7.0)

C8 exceed warming of 4°C (>50%)

Very high (SSP5-8.5)

Box SPM.1, Table 1: Description and relationship of scenarios and modelled pathways considered across AR6 Working Group

reports. {Cross-Section Box.2 Figure 1}

* See footnote 21 for the SSPx-y terminology.

** See footnote 23 for the RCPy terminology.

*** Limited overshoot refers to exceeding 1.5°C global warming by up to about 0.1°C, high overshoot by 0.1°C-0.3°C, in both

cases for up to several decades.

Current Mitigation Progress, Gaps and Challenges

A.4 Policies and laws addressing mitigation have consistently expanded since AR5. Global GHG

emissions in 2030 implied by nationally determined contributions (NDCs) announced by October

2021 make it likely that warming will exceed 1.5°C during the 21st century and make it harder

to limit warming below 2°C. There are gaps between projected emissions from implemented

policies and those from NDCs and ﬁnance ﬂows fall short of the levels needed to meet climate

goals across all sectors and regions. (high conﬁdence) {2.2, 2.3, Figure 2.5, Table 2.2}

A.4.1 The UNFCCC, Kyoto Protocol, and the Paris Agreement are supporting rising levels of national ambition. The Paris Agreement,

adopted under the UNFCCC, with near universal participation, has led to policy development and target-setting at national

and sub-national levels, in particular in relation to mitigation, as well as enhanced transparency of climate

action and support (medium conﬁdence). Many regulatory and economic instruments have already been deployed

successfully (high conﬁdence). In many countries, policies have enhanced energy efﬁciency, reduced rates of deforestation

and accelerated technology deployment, leading to avoided and in some cases reduced or removed emissions (high

conﬁdence). Multiple lines of evidence suggest that mitigation policies have led to several

Gt CO

-eq yr

-1

of avoided

global emissions (medium conﬁdence). At least 18 countries have sustained absolute production-based GHG and

consumption-based CO

reductions

for longer than 10 years. These reductions have only partly offset global emissions

growth (high conﬁdence). {2.2.1, 2.2.2}

A.4.2 Several mitigation options, notably solar energy, wind energy, electriﬁcation of urban systems, urban green infrastructure,

energy efﬁciency, demand-side management, improved forest and crop / grassland management, and reduced food

waste and loss, are technically viable, are becoming increasingly cost effective and are generally supported by the

At least 1.8 GtCO

-eq yr

–1

can be accounted for by aggregating separate estimates for the effects of economic and regulatory instruments. Growing

numbers of laws and executive orders have impacted global emissions and were estimated to result in 5.9 GtCO

-eq yr

–1

less emissions in 2016 than they

otherwise would have been. (medium conﬁdence) {2.2.2}

Reductions were linked to energy supply decarbonisation, energy efﬁciency gains, and energy demand reduction, which resulted from both policies and

changes in economic structure (high conﬁdence). {2.2.2}

Summary for Policymakers

public. From 2010 to 2019 there have been sustained decreases in the unit costs of solar energy (85%), wind energy

(55%), and lithium-ion batteries (85%), and large increases in their deployment, e.g., >10× for solar and >100× for

electric vehicles (EVs), varying widely across regions. The mix of policy instruments that reduced costs and stimulated

adoption includes public R&D, funding for demonstration and pilot projects, and demand-pull instruments such as

deployment subsidies to attain scale. Maintaining emission-intensive systems may, in some regions and sectors, be

more expensive than transitioning to low emission systems. (high conﬁdence) {2.2.2, Figure 2.4}

A.4.3 A substantial ‘emissions gap’ exists between global GHG emissions in 2030 associated with the implementation of

NDCs announced prior to COP26

and those associated with modelled mitigation pathways that limit warming to 1.5°C

(>50%) with no or limited overshoot or limit warming to 2°C (>67%) assuming immediate action (high conﬁdence). This

would make it likely that warming will exceed 1.5°C during the 21st century (high conﬁdence). Global modelled mitigation

pathways that limit warming to 1.5°C (>50%) with no or limited overshoot or limit warming to 2°C (>67%) assuming

immediate action imply deep global GHG emissions reductions this decade (high conﬁdence) (see SPM Box 1, Table 1, B.6)

Modelled pathways that are consistent with NDCs announced prior to COP26 until 2030 and assume no increase in

ambition thereafter have higher emissions, leading to a median global warming of 2.8 [2.1 to 3.4] °C by 2100 (medium

conﬁdence). Many countries have signalled an intention to achieve net zero GHG or net zero CO

by around mid-century

but pledges differ across countries in terms of scope and speciﬁcity, and limited policies are to date in place to deliver

on them. {2.3.1, Table 2.2, Figure 2.5, Table 3.1, 4.1}

A.4.4 Policy coverage is uneven across sectors (high conﬁdence). Policies implemented by the end of 2020 are projected to

result in higher global GHG emissions in 2030 than emissions implied by NDCs, indicating an ‘implementation gap’

(high conﬁdence). Without a strengthening of policies, global warming of 3.2 [2.2 to 3.5]°C is projected by 2100

(medium conﬁdence). {2.2.2, 2.3.1, 3.1.1, Figure 2.5} (Box SPM.1, Figure SPM.5)

A.4.5 The adoption of low-emission technologies lags in most developing countries, particularly least developed ones, due

in part to limited ﬁnance, technology development and transfer, and capacity (medium conﬁdence). The magnitude

of climate ﬁnance ﬂows has increased over the last decade and ﬁnancing channels have broadened but growth has

slowed since 2018 (high conﬁdence). Financial ﬂows have developed heterogeneously across regions and sectors

(high conﬁdence). Public and private ﬁnance ﬂows for fossil fuels are still greater than those for climate adaptation

and mitigation (high conﬁdence). The overwhelming majority of tracked climate ﬁnance is directed towards mitigation,

but nevertheless falls short of the levels needed to limit warming to below 2°C or to 1.5°C across all sectors and

regions (see C7.2) (very high conﬁdence). In 2018, public and publicly mobilised private climate ﬁnance ﬂows from

developed to developing countries were below the collective goal under the UNFCCC and Paris Agreement to mobilise

USD 100 billion per year by 2020 in the context of meaningful mitigation action and transparency on implementation

(medium conﬁdence). {2.2.2, 2.3.1, 2.3.3}

Due to the literature cutoff date of WGIII, the additional NDCs submitted after 11 October 2021 are not assessed here. {Footnote 32 in the Longer Report}

Projected 2030 GHG emissions are 50 (47–55) GtCO

-eq if all conditional NDC elements are taken into account. Without conditional elements, the global

emissions are projected to be approximately similar to modelled 2019 levels at 53 (50–57) GtCO

-eq. {2.3.1, Table 2.2}

Summary for Policymakers

B. Future Climate Change, Risks, and Long-Term Responses

Future Climate Change

B.1 Continued greenhouse gas emissions will lead to increasing global warming, with the best

estimate of reaching 1.5°C in the near term in considered scenarios and modelled pathways.

Every increment of global warming will intensify multiple and concurrent hazards (high

conﬁdence). Deep, rapid, and sustained reductions in greenhouse gas emissions would

lead to a discernible slowdown in global warming within around two decades, and also

to discernible changes in atmospheric composition within a few years (high conﬁdence).

{Cross-Section Boxes 1 and 2, 3.1, 3.3, Table 3.1, Figure 3.1, 4.3} (Figure SPM.2, Box SPM.1)

B.1.1 Global warming

will continue to increase in the near term (2021–2040) mainly due to increased cumulative

emissions in nearly all considered scenarios and modelled pathways. In the near term, global warming is more

likely than not to reach 1.5°C even under the very low GHG emission scenario (SSP1-1.9) and likely or very likely to

exceed 1.5°C under higher emissions scenarios. In the considered scenarios and modelled pathways, the best estimates

of the time when the level of global warming of 1.5°C is reached lie in the near term

. Global warming declines back

to below 1.5°C by the end of the 21st century in some scenarios and modelled pathways (see B.7). The assessed

climate response to GHG emissions scenarios results in a best estimate of warming for 2081–2100 that spans a range

from 1.4°C for a very low GHG emissions scenario (SSP1-1.9) to 2.7°C for an intermediate GHG emissions scenario

(SSP2-4.5) and 4.4°C for a very high GHG emissions scenario (SSP5-8.5)

, with narrower uncertainty ranges

than for

corresponding scenarios in AR5. {Cross-Section Boxes 1 and 2, 3.1.1, 3.3.4, Table 3.1, 4.3} (Box SPM.1)

B.1.2 Discernible differences in trends of global surface temperature between contrasting GHG emissions scenarios (SSP1-1.9

and SSP1-2.6 vs. SSP3-7.0 and SSP5-8.5) would begin to emerge from natural variability

within around 20 years. Under

these contrasting scenarios, discernible effects would emerge within years for GHG concentrations, and sooner for air

quality improvements, due to the combined targeted air pollution controls and strong and sustained methane emissions

reductions. Targeted reductions of air pollutant emissions lead to more rapid improvements in air quality within years

compared to reductions in GHG emissions only, but in the long term, further improvements are projected in scenarios

that combine efforts to reduce air pollutants as well as GHG emissions

. (high conﬁdence) {3.1.1} (Box SPM.1)

B.1.3 Continued emissions will further affect all major climate system components. With every additional increment of global

warming, changes in extremes continue to become larger. Continued global warming is projected to further intensify

the global water cycle, including its variability, global monsoon precipitation, and very wet and very dry weather and

Global warming (see Annex I: Glossary) is here reported as running 20-year averages, unless stated otherwise, relative to 1850–1900. Global surface

temperature in any single year can vary above or below the long-term human-caused trend, due to natural variability. The internal variability of global

surface temperature in a single year is estimated to be about ±0.25°C (5–95% range, high conﬁdence). The occurrence of individual years with global

surface temperature change above a certain level does not imply that this global warming level has been reached. {4.3, Cross-Section Box.2}

Median ﬁve-year interval at which a 1.5°C global warming level is reached (50% probability) in categories of modelled pathways considered in WGIII is

2030–2035. By 2030, global surface temperature in any individual year could exceed 1.5°C relative to 1850–1900 with a probability between 40% and

60%, across the ﬁve scenarios assessed in WGI (medium conﬁdence). In all scenarios considered in WGI except the very high emissions scenario (SSP5-8.5),

the midpoint of the ﬁrst 20-year running average period during which the assessed average global surface temperature change reaches 1.5°C lies in the

ﬁrst half of the 2030s. In the very high GHG emissions scenario, the midpoint is in the late 2020s. {3.1.1, 3.3.1, 4.3} (Box SPM.1)

The best estimates [and very likely ranges] for the different scenarios are: 1.4 [1.0 to 1.8 ]°C (SSP1-1.9); 1.8 [1.3 to 2.4]°C (SSP1-2.6); 2.7 [2.1 to 3.5]°C

(SSP2-4.5); 3.6 [2.8 to 4.6]°C (SSP3-7.0); and 4.4 [3.3 to 5.7 ]°C (SSP5-8.5). {3.1.1} (Box SPM.1)

Assessed future changes in global surface temperature have been constructed, for the ﬁrst time, by combining multi-model projections with observational

constraints and the assessed equilibrium climate sensitivity and transient climate response. The uncertainty range is narrower than in the AR5 thanks to

improved knowledge of climate processes, paleoclimate evidence and model-based emergent constraints. {3.1.1}

See Annex I: Glossary. Natural variability includes natural drivers and internal variability. The main internal variability phenomena include El Niño-Southern

Oscillation, Paciﬁc Decadal Variability and Atlantic Multi-decadal Variability. {4.3}

Based on additional scenarios.

Summary for Policymakers

climate events and seasons (high conﬁdence). In scenarios with increasing CO

emissions, natural land and ocean

carbon sinks are projected to take up a decreasing proportion of these emissions (high conﬁdence). Other projected

changes include further reduced extents and/or volumes of almost all cryospheric elements

(high conﬁdence), further

global mean sea level rise (virtually certain), and increased ocean acidiﬁcation (virtually certain) and deoxygenation

(high conﬁdence). {3.1.1, 3.3.1, Figure 3.4} (Figure SPM.2)

B.1.4 With further warming, every region is projected to increasingly experience concurrent and multiple changes in climatic

impact-drivers. Compound heatwaves and droughts are projected to become more frequent, including concurrent

events across multiple locations (high conﬁdence). Due to relative sea level rise, current 1-in-100 year extreme sea

level events are projected to occur at least annually in more than half of all tide gauge locations by 2100 under all

considered scenarios (high conﬁdence). Other projected regional changes include intensiﬁcation of tropical cyclones

and/or extratropical storms (medium conﬁdence), and increases in aridity and ﬁre weather (medium to high conﬁdence).

{3.1.1, 3.1.3}

B.1.5 Natural variability will continue to modulate human-caused climate changes, either attenuating or amplifying projected

changes, with little effect on centennial-scale global warming (high conﬁdence). These modulations are important to

consider in adaptation planning, especially at the regional scale and in the near term. If a large explosive volcanic

eruption were to occur

, it would temporarily and partially mask human-caused climate change by reducing global

surface temperature and precipitation for one to three years (medium conﬁdence). {4.3}

Permafrost, seasonal snow cover, glaciers, the Greenland and Antarctic Ice Sheets, and Arctic sea ice.

Based on 2500-year reconstructions, eruptions with a radiative forcing more negative than –1 W m

-2

, related to the radiative effect of volcanic stratospheric

aerosols in the literature assessed in this report, occur on average twice per century. {4.3}

Summary for Policymakers

2011-2020 was

around 1.1°C warmer

than 1850-1900

the last time global surface temperature was sustained

at or above 2.5°C was over 3 million years ago

4°C

The world at

2°C

The world at

1.5°C

+ +

The world at

3°C

The world at

small absolute

changes may

appear large as

% or σ changes

in dry regions

urbanisation

further intensifies

heat extremes

c) Annual wettest-day precipitation change

Global warming level (GWL) above 1850-1900

a) Annual hottest-day temperature change

b) Annual mean total column soil moisture change

°C

Annual wettest day precipitation is projected to increase

in almost all continental regions, even in regions where

projected annual mean soil moisture declines.

Annual hottest day temperature is projected to increase most

(1.5-2 times the GWL) in some mid-latitude and semi-arid

regions, and in the South American Monsoon region.

Projections of annual mean soil moisture largely follow

projections in annual mean precipitation but also show

some differences due to the inﬂuence of evapotranspiration.

change (%)

-40 -30 -20 -10 0 10 20 30 40

+ +

change (°C)

0 1 2 3 4 5 6 7

-1.5 -1.0 -0.5 0 0.5 1.0 1.5

change (σ)

With every increment of global warming, regional changes in mean

climate and extremes become more widespread and pronounced

Figure SPM.2: Projected changes of annual maximum daily maximum temperature, annual mean total column soil moisture and annual

maximum 1-day precipitation at global warming levels of 1.5°C, 2°C, 3°C, and 4°C relative to 1850–1900. Projected (a) annual maximum

daily temperature change (°C), (b) annual mean total column soil moisture change (standard deviation), (c) annual maximum 1-day precipitation change (%).

The panels show CMIP6 multi-model median changes. In panels (b) and (c), large positive relative changes in dry regions may correspond to small absolute

changes. In panel (b), the unit is the standard deviation of interannual variability in soil moisture during 1850–1900. Standard deviation is a widely used

metric in characterising drought severity. A projected reduction in mean soil moisture by one standard deviation corresponds to soil moisture conditions typical

of droughts that occurred about once every six years during 1850–1900. The WGI Interactive Atlas (https://interactive-atlas.ipcc.ch/) can be used to explore

additional changes in the climate system across the range of global warming levels presented in this ﬁgure. {Figure 3.1, Cross-Section Box.2}

Climate Change Impacts and Climate-Related Risks

B.2 For any given future warming level, many climate-related risks are higher than assessed in

AR5, and projected long-term impacts are up to multiple times higher than currently observed

(high conﬁdence). Risks and projected adverse impacts and related losses and damages from

climate change escalate with every increment of global warming (very high conﬁdence).

Climatic and non-climatic risks will increasingly interact, creating compound and cascading

risks that are more complex and difﬁcult to manage (high conﬁdence). {Cross-Section Box.2,

3.1, 4.3, Figure 3.3, Figure 4.3} (Figure SPM.3, Figure SPM.4)

Summary for Policymakers

B.2.1 In the near term, every region in the world is projected to face further increases in climate hazards (medium to

high conﬁdence, depending on region and hazard), increasing multiple risks to ecosystems and humans (very high

conﬁdence). Hazards and associated risks expected in the near term include an increase in heat-related human mortality

and morbidity (high conﬁdence), food-borne, water-borne, and vector-borne diseases (high conﬁdence), and mental

health challenges

(very high conﬁdence), ﬂooding in coastal and other low-lying cities and regions (high conﬁdence),

biodiversity loss in land, freshwater and ocean ecosystems (medium to very high conﬁdence, depending on ecosystem),

and a decrease in food production in some regions (high conﬁdence). Cryosphere-related changes in ﬂoods, landslides,

and water availability have the potential to lead to severe consequences for people, infrastructure and the economy in

most mountain regions (high conﬁdence). The projected increase in frequency and intensity of heavy precipitation (high

conﬁdence) will increase rain-generated local ﬂooding (medium conﬁdence). {Figure 3.2, Figure 3.3, 4.3, Figure 4.3}

(Figure SPM.3, Figure SPM.4)

B.2.2 Risks and projected adverse impacts and related losses and damages from climate change will escalate with every

increment of global warming (very high conﬁdence). They are higher for global warming of 1.5°C than at present, and

even higher at 2°C (high conﬁdence). Compared to the AR5, global aggregated risk levels

(Reasons for Concern

) are

assessed to become high to very high at lower levels of global warming due to recent evidence of observed impacts,

improved process understanding, and new knowledge on exposure and vulnerability of human and natural systems,

including limits to adaptation (high conﬁdence). Due to unavoidable sea level rise (see also B.3), risks for coastal

ecosystems, people and infrastructure will continue to increase beyond 2100 (high conﬁdence). {3.1.2, 3.1.3, Figure 3.4,

Figure 4.3} (Figure SPM.3, Figure SPM.4)

B.2.3 With further warming, climate change risks will become increasingly complex and more difﬁcult to manage. Multiple

climatic and non-climatic risk drivers will interact, resulting in compounding overall risk and risks cascading across

sectors and regions. Climate-driven food insecurity and supply instability, for example, are projected to increase with

increasing global warming, interacting with non-climatic risk drivers such as competition for land between urban

expansion and food production, pandemics and conﬂict. (high conﬁdence) {3.1.2, 4.3, Figure 4.3}

B.2.4 For any given warming level, the level of risk will also depend on trends in vulnerability and exposure of humans and

ecosystems. Future exposure to climatic hazards is increasing globally due to socio-economic development trends

including migration, growing inequality and urbanisation. Human vulnerability will concentrate in informal settlements

and rapidly growing smaller settlements. In rural areas vulnerability will be heightened by high reliance on climate-

sensitive livelihoods. Vulnerability of ecosystems will be strongly inﬂuenced by past, present, and future patterns of

unsustainable consumption and production, increasing demographic pressures, and persistent unsustainable use and

management of land, ocean, and water. Loss of ecosystems and their services has cascading and long-term impacts on

people globally, especially for Indigenous Peoples and local communities who are directly dependent on ecosystems to

meet basic needs. (high conﬁdence) {Cross-Section Box.2 Figure 1c, 3.1.2, 4.3}

In all assessed regions.

Undetectable risk level indicates no associated impacts are detectable and attributable to climate change; moderate risk indicates associated impacts are

both detectable and attributable to climate change with at least medium conﬁdence, also accounting for the other speciﬁc criteria for key risks; high risk

indicates severe and widespread impacts that are judged to be high on one or more criteria for assessing key risks; and very high risk level indicates very

high risk of severe impacts and the presence of signiﬁcant irreversibility or the persistence of climate-related hazards, combined with limited ability to adapt

due to the nature of the hazard or impacts/risks. {3.1.2}

The Reasons for Concern (RFC) framework communicates scientiﬁc understanding about accrual of risk for ﬁve broad categories. RFC1: Unique and

threatened systems: ecological and human systems that have restricted geographic ranges constrained by climate-related conditions and have high

endemism or other distinctive properties. RFC2: Extreme weather events: risks/impacts to human health, livelihoods, assets and ecosystems from extreme

weather events. RFC3: Distribution of impacts: risks/impacts that disproportionately affect particular groups due to uneven distribution of physical climate

change hazards, exposure or vulnerability. RFC4: Global aggregate impacts: impacts to socio-ecological systems that can be aggregated globally into a

single metric. RFC5: Large-scale singular events: relatively large, abrupt and sometimes irreversible changes in systems caused by global warming. See also

Annex I: Glossary. {3.1.2, Cross-Section Box.2}

Summary for Policymakers

c1) Maize yield

c2) Fisheries yield

Changes (%) in

maximum catch

potential

Changes (%) in yield

-20 -10 -3-30 -25 -15-35% +20 +30 +35%+10+3 +25+15

10 days

300100 20010 150 25050 365 days

0.10% 8010 401 20 605 100%

Areas with model disagreement

Examples of impacts without additional adaptation

2.4 – 3.1°C 4.2 – 5.4°C

1.5°C

3.0°C

1.7 – 2.3°C

0.9 – 2.0°C 3.4 – 5.2°C

1.6 – 2.4°C 3.3 – 4.8°C 3.9 – 6.0°C

2.0°C

4.0°C

Percentage of animal

species and seagrasses

exposed to potentially

dangerous temperature

conditions

1, 2

Days per year where

combined temperature and

humidity conditions pose a risk

of mortality to individuals

Projected regional impacts reﬂect ﬁsheries and marine ecosystem responses to ocean physical and biogeochemical conditions such as

temperature, oxygen level and net primary production. Models do not represent changes in ﬁshing activities and some extreme climatic

conditions. Projected changes in the Arctic regions have low conﬁdence due to uncertainties associated with modelling multiple interacting

drivers and ecosystem responses.

Projected regional impacts reﬂect biophysical responses to changing temperature, precipitation, solar radiation, humidity, wind, and CO

enhancement of growth and water retention in currently cultivated areas. Models assume that irrigated areas are not water-limited.

Models do not represent pests, diseases, future agro-technological changes and some extreme climate responses.

Future climate change is projected to increase the severity of impacts

across natural and human systems and will increase regional differences

Areas with little or no

production, or not assessed

Projected temperature conditions above

the estimated historical (1850-2005)

maximum mean annual temperature

experienced by each species, assuming

no species relocation.

Includes 30,652 species of birds,

mammals, reptiles, amphibians, marine

ﬁsh, benthic marine invertebrates, krill,

cephalopods, corals, and seagrasses.

a) Risk of

species losses

b) Heat-humidity

risks to

human health

c) Food production

impacts

Projected regional impacts utilize a global threshold beyond which daily mean surface air temperature and relative humidity may induce

hyperthermia that poses a risk of mortality. The duration and intensity of heatwaves are not presented here. Heat-related health outcomes

vary by location and are highly moderated by socio-economic, occupational and other non-climatic determinants of individual health and

socio-economic vulnerability. The threshold used in these maps is based on a single study that synthesized data from 783 cases to

determine the relationship between heat-humidity conditions and mortality drawn largely from observations in temperate climates.

Historical 1991–2005

Figure SPM.3: Projected risks and impacts of climate change on natural and human systems at different global warming levels (GWLs) relative to 1850–1900

levels. Projected risks and impacts shown on the maps are based on outputs from different subsets of Earth system and impact models that were used to project

each impact indicator without additional adaptation. WGII provides further assessment of the impacts on human and natural systems using these projections

and additional lines of evidence. (a) Risks of species losses as indicated by the percentage of assessed species exposed to potentially dangerous temperature

conditions, as deﬁned by conditions beyond the estimated historical (1850–2005) maximum mean annual temperature experienced by each species, at GWLs

of 1.5°C, 2°C, 3°C and 4°C. Underpinning projections of temperature are from 21 Earth system models and do not consider extreme events impacting

ecosystems such as the Arctic. (b) Risks to human health as indicated by the days per year of population exposure to hyperthermic conditions that pose a risk

of mortality from surface air temperature and humidity conditions for historical period (1991–2005) and at GWLs of 1.7°C–2.3°C (mean = 1.9°C; 13 climate

models), 2.4°C–3.1°C (2.7°C; 16 climate models) and 4.2°C–5.4°C (4.7°C; 15 climate models). Interquartile ranges of GWLs by 2081–2100 under RCP2.6,

RCP4.5 and RCP8.5. The presented index is consistent with common features found in many indices included within WGI and WGII assessments. (c) Impacts

on food production: (c1) Changes in maize yield by 2080–2099 relative to 1986–2005 at projected GWLs of 1.6°C–2.4°C (2.0°C), 3.3°C–4.8°C (4.1°C) and

3.9°C–6.0°C (4.9°C). Median yield changes from an ensemble of 12 crop models, each driven by bias-adjusted outputs from 5 Earth system models, from

the Agricultural Model Intercomparison and Improvement Project (AgMIP) and the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). Maps depict

Summary for Policymakers

2080–2099 compared to 1986–2005 for current growing regions (>10 ha), with the corresponding range of future global warming levels shown under SSP1-

2.6, SSP3-7.0 and SSP5-8.5, respectively. Hatching indicates areas where <70% of the climate-crop model combinations agree on the sign of impact. (c2)

Change in maximum ﬁsheries catch potential by 2081–2099 relative to 1986–2005 at projected GWLs of 0.9°C–2.0°C (1.5°C) and 3.4°C–5.2°C (4.3°C).

GWLs by 2081–2100 under RCP2.6 and RCP8.5. Hatching indicates where the two climate-ﬁsheries models disagree in the direction of change. Large relative

changes in low yielding regions may correspond to small absolute changes. Biodiversity and ﬁsheries in Antarctica were not analysed due to data limitations.

Food security is also affected by crop and ﬁshery failures not presented here. {3.1.2, Figure 3.2, Cross-Section Box.2} (Box SPM.1)

Salt

marshes

Rocky

shores

Seagrass

meadows

EpipelagicWarm-water

corals

Kelp

forests

AR5 AR6 AR5 AR6 AR5 AR6 AR5 AR6AR5 AR6

Global surface temperature change

relative to 1850–1900

Global Reasons for Concern (RFCs)

in AR5 (2014) vs. AR6 (2022)

°C

1.5

°C

–1

2000 2015 2050 2100

very low

low

intermediate

high

very high

••••

•••••••

•••••••••

•••••••

••••••

•• •• ••

damage

Wildﬁre

•••••••

Dryland

water

scarcity

•••••••

1.5

Incomplete

adaptation

Proactive

adaptation

Limited

adaptation

••••

•• •• ••

Heat-related morbidity and mortality

high

Challenges to Adaptation

low

•••

••••

•••••••••

••••••••••

•••••••

•••••

•••••••

Conﬁdence level

assigned to

transition range

midpoint of transition

Risk/impact

Low Very high

Very high

High

Moderate

Undetectable

•

•••

••

••••

Transition range

°C

Permafrost

degradation

••• •••••

e.g. increase in the

length of ﬁre season

e.g. over 100 million

additional people

exposed

–1

1950 2000 2015 2050

100

Resource-rich

coastal cities

Large tropical

agricultural

deltas

Arctic

communities

Urban

atoll islands

Maximum potential

response

No-to-moderate

response

r Rr Rr Rr R

Global mean sea level rise relative to 1900

100

1950 2000 2050 2100

cm cm

very high

high

intermediate

low

very low

c) Risks to coastal geographies increase with sea level rise and depend on responses

1986-2005

baseline

low-likelihood, high impact

storyline, including ice-sheet

instability processes

•••••••••

••••

•••••••

d) Adaptation and

socio-economic pathways

affect levels of climate

related risks

b) Risks differ by system

SSP1SSP3

Risks are increasing with every increment of warming

Global

aggregate

impacts

Unique &

threatened

systems

Extreme

weather

events

Distribution

of impacts

Large scale

singular

events

risk is the potential for

adverse consequences

•••••••

Tree

mortality

e.g. coral

reefs decline

>99%

e.g. coral

reefs decline

by 70–90%

Land-based systems Ocean/coastal ecosystems

Food insecurity

(availability, access)

a) High risks are now assessed to occur at lower global warming levels

The SSP1 pathway illustrates

a world with low population

growth, high income, and

reduced inequalities, food

produced in low GHG

emission systems, effective

land use regulation and high

adaptive capacity (i.e., low

challenges to adaptation).

The SSP3 pathway has the

opposite trends.

shading represents the

uncertainty ranges for

the low and high

emissions scenarios

2011-2020 was

around 1.1°C warmer

than 1850-1900

Carbon

loss

••• ••

••

•••

Biodiversity

loss

Risks are

assessed with

medium conﬁdence

Limited adaptation (failure to proactively

adapt; low investment in health systems);

incomplete adaptation (incomplete

adaptation planning; moderate investment

in health systems); proactive adaptation

(proactive adaptation management; higher

investment in health systems)

Summary for Policymakers

Figure SPM.4: Subset of assessed climate outcomes and associated global and regional climate risks. The burning embers result from a literature

based expert elicitation. Panel (a): Left – Global surface temperature changes in °C relative to 1850–1900. These changes were obtained by combining CMIP6

model simulations with observational constraints based on past simulated warming, as well as an updated assessment of equilibrium climate sensitivity. Very

likely ranges are shown for the low and high GHG emissions scenarios (SSP1-2.6 and SSP3-7.0) (Cross-Section Box.2). Right – Global Reasons for Concern

(RFC), comparing AR6 (thick embers) and AR5 (thin embers) assessments. Risk transitions have generally shifted towards lower temperatures with updated

scientiﬁc understanding. Diagrams are shown for each RFC, assuming low to no adaptation. Lines connect the midpoints of the transitions from moderate to high

risk across AR5 and AR6. Panel (b): Selected global risks for land and ocean ecosystems, illustrating general increase of risk with global warming levels with low

to no adaptation. Panel (c): Left - Global mean sea level change in centimetres, relative to 1900. The historical changes (black) are observed by tide gauges

before 1992 and altimeters afterwards. The future changes to 2100 (coloured lines and shading) are assessed consistently with observational constraints based

on emulation of CMIP, ice-sheet, and glacier models, and likely ranges are shown for SSP1-2.6 and SSP3-7.0. Right - Assessment of the combined risk of coastal

ﬂooding, erosion and salinization for four illustrative coastal geographies in 2100, due to changing mean and extreme sea levels, under two response scenarios,

with respect to the SROCC baseline period (1986–2005). The assessment does not account for changes in extreme sea level beyond those directly induced by

mean sea level rise; risk levels could increase if other changes in extreme sea levels were considered (e.g., due to changes in cyclone intensity). “No-to-moderate

response” describes efforts as of today (i.e., no further signiﬁcant action or new types of actions). “Maximum potential response” represent a combination of

responses implemented to their full extent and thus signiﬁcant additional efforts compared to today, assuming minimal ﬁnancial, social and political barriers.

(In this context, ‘today’ refers to 2019.) The assessment criteria include exposure and vulnerability, coastal hazards, in-situ responses and planned relocation.

Planned relocation refers to managed retreat or resettlements. The term response is used here instead of adaptation because some responses, such as retreat,

may or may not be considered to be adaptation. Panel (d): Selected risks under different socio-economic pathways, illustrating how development strategies

and challenges to adaptation inﬂuence risk. Left - Heat-sensitive human health outcomes under three scenarios of adaptation effectiveness. The diagrams are

truncated at the nearest whole ºC within the range of temperature change in 2100 under three SSP scenarios. Right - Risks associated with food security due to

climate change and patterns of socio-economic development. Risks to food security include availability and access to food, including population at risk of hunger,

food price increases and increases in disability adjusted life years attributable to childhood underweight. Risks are assessed for two contrasted socio-economic

pathways (SSP1 and SSP3) excluding the effects of targeted mitigation and adaptation policies. {Figure 3.3} (Box SPM.1)

Likelihood and Risks of Unavoidable, Irreversible or Abrupt

Changes

B.3 Some future changes are unavoidable and/or irreversible but can be limited by deep, rapid,

and sustained global greenhouse gas emissions reductions. The likelihood of abrupt and/or

irreversible changes increases with higher global warming levels. Similarly, the probability

of low-likelihood outcomes associated with potentially very large adverse impacts increases

with higher global warming levels. (high conﬁdence) {3.1}

B.3.1 Limiting global surface temperature does not prevent continued changes in climate system components that have

multi-decadal or longer timescales of response (high conﬁdence). Sea level rise is unavoidable for centuries to millennia

due to continuing deep ocean warming and ice sheet melt, and sea levels will remain elevated for thousands of years

(high conﬁdence). However, deep, rapid, and sustained GHG emissions reductions would limit further sea level rise

acceleration and projected long-term sea level rise commitment. Relative to 1995–2014, the likely global mean sea

level rise under the SSP1-1.9 GHG emissions scenario is 0.15–0.23 m by 2050 and 0.28–0.55 m by 2100; while for the

SSP5-8.5 GHG emissions scenario it is 0.20–0.29 m by 2050 and 0.63–1.01 m by 2100 (medium conﬁdence). Over the

next 2000 years, global mean sea level will rise by about 2–3 m if warming is limited to 1.5°C and 2–6 m if limited to

2°C (low conﬁdence). {3.1.3, Figure 3.4} (Box SPM.1)

B.3.2 The likelihood and impacts of abrupt and/or irreversible changes in the climate system, including changes triggered

when tipping points are reached, increase with further global warming (high conﬁdence). As warming levels increase, so

do the risks of species extinction or irreversible loss of biodiversity in ecosystems including forests (medium conﬁdence),

coral reefs (very high conﬁdence) and in Arctic regions (high conﬁdence). At sustained warming levels between 2°C and

3°C, the Greenland and West Antarctic ice sheets will be lost almost completely and irreversibly over multiple millennia,

causing several metres of sea level rise (limited evidence). The probability and rate of ice mass loss increase with higher

global surface temperatures (high conﬁdence). {3.1.2, 3.1.3}

B.3.3 The probability of low-likelihood outcomes associated with potentially very large impacts increases with higher global

warming levels (high conﬁdence). Due to deep uncertainty linked to ice-sheet processes, global mean sea level rise

above the likely range – approaching 2 m by 2100 and in excess of 15 m by 2300 under the very high GHG emissions

scenario (SSP5-8.5) (low conﬁdence) – cannot be excluded. There is medium conﬁdence that the Atlantic Meridional

Overturning Circulation will not collapse abruptly before 2100, but if it were to occur, it would very likely cause abrupt

shifts in regional weather patterns, and large impacts on ecosystems and human activities. {3.1.3} (Box SPM.1)

Summary for Policymakers

Adaptation Options and their Limits in a Warmer World

B.4 Adaptation options that are feasible and effective today will become constrained and

less effective with increasing global warming. With increasing global warming, losses and

damages will increase and additional human and natural systems will reach adaptation

limits. Maladaptation can be avoided by ﬂexible, multi-sectoral, inclusive, long-term

planning and implementation of adaptation actions, with co-beneﬁts to many sectors and

systems. (high conﬁdence) {3.2, 4.1, 4.2, 4.3}

B.4.1 The effectiveness of adaptation, including ecosystem-based and most water-related options, will decrease with

increasing warming. The feasibility and effectiveness of options increase with integrated, multi-sectoral solutions that

differentiate responses based on climate risk, cut across systems and address social inequities. As adaptation options

often have long implementation times, long-term planning increases their efﬁciency. (high conﬁdence) {3.2, Figure 3.4,

4.1, 4.2}

B.4.2 With additional global warming, limits to adaptation and losses and damages, strongly concentrated among vulnerable

populations, will become increasingly difﬁcult to avoid (high conﬁdence). Above 1.5°C of global warming, limited

freshwater resources pose potential hard adaptation limits for small islands and for regions dependent on glacier

and snow melt (medium conﬁdence). Above that level, ecosystems such as some warm-water coral reefs, coastal

wetlands, rainforests, and polar and mountain ecosystems will have reached or surpassed hard adaptation limits and as

a consequence, some Ecosystem-based Adaptation measures will also lose their effectiveness (high conﬁdence). {2.3.2,

3.2, 4.3}

B.4.3 Actions that focus on sectors and risks in isolation and on short-term gains often lead to maladaptation over the long

term, creating lock-ins of vulnerability, exposure and risks that are difﬁcult to change. For example, seawalls effectively

reduce impacts to people and assets in the short term but can also result in lock-ins and increase exposure to climate

risks in the long term unless they are integrated into a long-term adaptive plan. Maladaptive responses can worsen

existing inequities especially for Indigenous Peoples and marginalised groups and decrease ecosystem and biodiversity

resilience. Maladaptation can be avoided by ﬂexible, multi-sectoral, inclusive, long-term planning and implementation

of adaptation actions, with co-beneﬁts to many sectors and systems. (high conﬁdence) {2.3.2, 3.2}

Carbon Budgets and Net Zero Emissions

B.5 Limiting human-caused global warming requires net zero CO

emissions. Cumulative carbon

emissions until the time of reaching net zero CO

emissions and the level of greenhouse

gas emission reductions this decade largely determine whether warming can be limited to

1.5°C or 2°C (high conﬁdence). Projected CO

emissions from existing fossil fuel infrastructure

without additional abatement would exceed the remaining carbon budget for 1.5°C (50%)

(high conﬁdence). {2.3, 3.1, 3.3, Table 3.1}

B.5.1 From a physical science perspective, limiting human-caused global warming to a speciﬁc level requires limiting cumulative

emissions, reaching at least net zero CO

emissions, along with strong reductions in other greenhouse gas emissions.

Reaching net zero GHG emissions primarily requires deep reductions in CO

, methane, and other GHG emissions, and

implies net negative CO

emissions

. Carbon dioxide removal (CDR) will be necessary to achieve net negative CO

emissions (see B.6). Net zero GHG emissions, if sustained, are projected to result in a gradual decline in global surface

temperatures after an earlier peak. (high conﬁdence) {3.1.1, 3.3.1, 3.3.2, 3.3.3, Table 3.1, Cross-Section Box.1}

B.5.2 For every 1000 GtCO

emitted by human activity, global surface temperature rises by 0.45°C (best estimate, with a likely

range from 0.27°C to 0.63°C). The best estimates of the remaining carbon budgets from the beginning of 2020 are

500 GtCO

for a 50% likelihood of limiting global warming to 1.5°C and 1150 GtCO

for a 67% likelihood of limiting

warming to 2°C

. The stronger the reductions in non-CO

emissions, the lower the resulting temperatures are for a given

remaining carbon budget or the larger remaining carbon budget for the same level of temperature change

. {3.3.1}

Net zero GHG emissions deﬁned by the 100-year global warming potential. See footnote 9.

Global databases make different choices about which emissions and removals occurring on land are considered anthropogenic. Most countries report their

anthropogenic land CO

ﬂuxes including ﬂuxes due to human-caused environmental change (e.g., CO

fertilisation) on ‘managed’ land in their national

GHG inventories. Using emissions estimates based on these inventories, the remaining carbon budgets must be correspondingly reduced. {3.3.1}

For example, remaining carbon budgets could be 300 or 600 GtCO

for 1.5°C (50%), respectively for high and low non-CO

emissions, compared to

500 GtCO

in the central case. {3.3.1}

Summary for Policymakers

B.5.3 If the annual CO

emissions between 2020–2030 stayed, on average, at the same level as 2019, the resulting cumulative

emissions would almost exhaust the remaining carbon budget for 1.5°C (50%), and deplete more than a third of the

remaining carbon budget for 2°C (67%). Estimates of future CO

emissions from existing fossil fuel infrastructures

without additional abatement

already exceed the remaining carbon budget for limiting warming to 1.5°C (50%)

(high conﬁdence). Projected cumulative future CO

emissions over the lifetime of existing and planned fossil fuel

infrastructure, if historical operating patterns are maintained and without additional abatement

, are approximately

equal to the remaining carbon budget for limiting warming to 2°C with a likelihood of 83%

(high conﬁdence). {2.3.1,

3.3.1, Figure 3.5}

B.5.4 Based on central estimates only, historical cumulative net CO

emissions between 1850 and 2019 amount to about

four ﬁfths

of the total carbon budget for a 50% probability of limiting global warming to 1.5°C (central estimate about

2900 GtCO

), and to about two thirds

of the total carbon budget for a 67% probability to limit global warming to 2°C

(central estimate about 3550 GtCO

). {3.3.1, Figure 3.5}

Mitigation Pathways

B.6 All global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot,

and those that limit warming to 2°C (>67%), involve rapid and deep and, in most cases,

immediate greenhouse gas emissions reductions in all sectors this decade. Global net zero CO

emissions are reached for these pathway categories, in the early 2050s and around the early

2070s, respectively. (high conﬁdence) {3.3, 3.4, 4.1, 4.5, Table 3.1} (Figure SPM.5, Box SPM.1)

B.6.1 Global modelled pathways provide information on limiting warming to different levels; these pathways, particularly

their sectoral and regional aspects, depend on the assumptions described in Box SPM.1. Global modelled pathways that

limit warming to 1.5°C (>50%) with no or limited overshoot or limit warming to 2°C (>67%) are characterized by deep,

rapid, and, in most cases, immediate GHG emissions reductions. Pathways that limit warming to 1.5°C (>50%) with no

or limited overshoot reach net zero CO

in the early 2050s, followed by net negative CO

emissions. Those pathways that

reach net zero GHG emissions do so around the 2070s. Pathways that limit warming to 2°C (>67%) reach net zero CO

emissions in the early 2070s. Global GHG emissions are projected to peak between 2020 and at the latest before 2025

in global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot and in those that limit

warming to 2°C (>67%) and assume immediate action. (high conﬁdence) {3.3.2, 3.3.4, 4.1, Table 3.1, Figure 3.6} (Table

SPM.1)

Abatement here refers to human interventions that reduce the amount of greenhouse gases that are released from fossil fuel infrastructure to the

atmosphere.

Ibid.

WGI provides carbon budgets that are in line with limiting global warming to temperature limits with different likelihoods, such as 50%, 67% or 83%.

{3.3.1}

Uncertainties for total carbon budgets have not been assessed and could affect the speciﬁc calculated fractions.

Ibid.

Summary for Policymakers

Table SPM.1: Greenhouse gas and CO

emission reductions from 2019, median and 5-95 percentiles. {3.3.1, 4.1, Table 3.1, Figure 2.5, Box SPM.1}

Reductions from 2019 emission levels (%)

2030 2035 2040 2050

Limit warming to1.5°C (>50%) with no or

limited overshoot

GHG 43 [34-60] 60 [49-77] 69 [58-90] 84 [73-98]

48 [36-69] 65 [50-96] 80 [61-109] 99 [79-119]

Limit warming to 2°C (>67%)

GHG 21 [1-42] 35 [22-55] 46 [34-63] 64 [53-77]

22 [1-44] 37 [21-59] 51 [36-70] 73 [55-90]

B.6.2 Reaching net zero CO

or GHG emissions primarily requires deep and rapid reductions in gross emissions of CO

, as well

as substantial reductions of non-CO

GHG emissions (high conﬁdence). For example, in modelled pathways that limit

warming to 1.5°C (>50%) with no or limited overshoot, global methane emissions are reduced by 34 [21–57]% by 2030

relative to 2019. However, some hard-to-abate residual GHG emissions (e.g., some emissions from agriculture, aviation,

shipping, and industrial processes) remain and would need to be counterbalanced by deployment of CDR methods to

achieve net zero CO

or GHG emissions (high conﬁdence). As a result, net zero CO

is reached earlier than net zero GHGs

(high conﬁdence). {3.3.2, 3.3.3, Table 3.1, Figure 3.5} (Figure SPM.5)

B.6.3 Global modelled mitigation pathways reaching net zero CO

and GHG emissions include transitioning from fossil fuels

without carbon capture and storage (CCS) to very low- or zero-carbon energy sources, such as renewables or fossil fuels

with CCS, demand-side measures and improving efﬁciency, reducing non-CO

GHG emissions, and CDR

. In most global

modelled pathways, land-use change and forestry (via reforestation and reduced deforestation) and the energy supply

sector reach net zero CO

emissions earlier than the buildings, industry and transport sectors. (high conﬁdence) {3.3.3,

4.1, 4.5, Figure 4.1} (Figure SPM.5, Box SPM.1)

B.6.4 Mitigation options often have synergies with other aspects of sustainable development, but some options can also

have trade-offs. There are potential synergies between sustainable development and, for instance, energy efﬁciency

and renewable energy. Similarly, depending on the context

, biological CDR methods like reforestation, improved

forest management, soil carbon sequestration, peatland restoration and coastal blue carbon management can enhance

biodiversity and ecosystem functions, employment and local livelihoods. However, afforestation or production of

biomass crops can have adverse socio-economic and environmental impacts, including on biodiversity, food and water

security, local livelihoods and the rights of Indigenous Peoples, especially if implemented at large scales and where land

tenure is insecure. Modelled pathways that assume using resources more efﬁciently or that shift global development

towards sustainability include fewer challenges, such as less dependence on CDR and pressure on land and biodiversity.

(high conﬁdence) {3.4.1}

CCS is an option to reduce emissions from large-scale fossil-based energy and industry sources provided geological storage is available. When CO

captured directly from the atmosphere (DACCS), or from biomass (BECCS), CCS provides the storage component of these CDR methods. CO

capture and

subsurface injection is a mature technology for gas processing and enhanced oil recovery. In contrast to the oil and gas sector, CCS is less mature in the

power sector, as well as in cement and chemicals production, where it is a critical mitigation option. The technical geological storage capacity is estimated

to be on the order of 1000 GtCO

, which is more than the CO

storage requirements through 2100 to limit global warming to 1.5°C, although the regional

availability of geological storage could be a limiting factor. If the geological storage site is appropriately selected and managed, it is estimated that the CO

can be permanently isolated from the atmosphere. Implementation of CCS currently faces technological, economic, institutional, ecological-environmental

and socio-cultural barriers. Currently, global rates of CCS deployment are far below those in modelled pathways limiting global warming to 1.5°C to 2°C.

Enabling conditions such as policy instruments, greater public support and technological innovation could reduce these barriers. (high conﬁdence) {3.3.3}

The impacts, risks, and co-beneﬁts of CDR deployment for ecosystems, biodiversity and people will be highly variable depending on the method, site-speciﬁc

context, implementation and scale (high conﬁdence).

Summary for Policymakers

0

40

20

-20

60

80

2000

2020

2040

2060

2080

2100

0

200

400

MtCH

/yr GtCO

/yr

2000

2020

2040

2060

2080

2100

−20

20

40

60

2019

comparison

IMP-Neg

IMP-GS

IMP-Ren

IMP-LD

IMP-SP

Sources

Sinks

net zero

2000

2020

2040

2060

2080

2100

a) Net global greenhouse

gas (GHG) emissions

Gigatons of CO

-equivalent emissions (GtCO

-eq/yr)

GtCO

-eq/yr

−20

0

20

40

60

80

2000

2020

2040

2060

2080

2100

GHG

Year of net zero emissions

d) Net zero

will be reached

before

net zero GHG emissions

1.5°C

2°C

c) Global methane (CH

) emissions

net zero

Nationally Determined

Contributions (NDCs)

range in 2030

net zero

a) Net global greenhouse

gas (GHG) emissions

Key

Past emissions (2000–2015)

Model range for 2015 emissions

Past GHG emissions and uncertainty for

2015 and 2019 (dot indicates the median)

Implemented policies

(median, with

percentiles 25-75% and 5-95%)

Limit warming to 2°C (>67%)

Limit warming to 1.5°C (>50%)

with no or limited overshoot

Key

Transport, industry and buildings

Non-CO

emissions

Land-use change and forestry

Energy supply (including electricity)

these are dierent

ways to achieve

net-zero CO

b) Net global CO

emissions

e) Greenhouse gas emissions by

sector at the time of net zero

, compared to 2019

Limiting warming to 1.5°C and 2°C involves rapid, deep and

in most cases immediate greenhouse gas emission reductions

Net zero CO

and net zero GHG emissions can be achieved through strong reductions across all sectors

Implemented policies result in projected

emissions that lead to warming of 3.2°C, with

a range of 2.2°C to 3.5°C (

)

2019 emissions were

12% higher than 2010

Illustrative Mitigation

Pathways (IMPs)

Summary for Policymakers

Figure SPM.5: Global emissions pathways consistent with implemented policies and mitigation strategies. Panels (a), (b) and (c) show the

development of global GHG, CO

and methane emissions in modelled pathways, while panel (d) shows the associated timing of when GHG and CO

emissions

reach net zero. Coloured ranges denote the 5th to 95th percentile across the global modelled pathways falling within a given category as described in Box SPM.1.

The red ranges depict emissions pathways assuming policies that were implemented by the end of 2020. Ranges of modelled pathways that limit warming to

1.5°C (>50%) with no or limited overshoot are shown in light blue (category C1) and pathways that limit warming to 2°C (>67%) are shown in green (category

C3). Global emission pathways that would limit warming to 1.5°C (>50%) with no or limited overshoot and also reach net zero GHG in the second half of the

century do so between 2070–2075. Panel (e) shows the sectoral contributions of CO

and non-CO

emissions sources and sinks at the time when net zero

emissions are reached in illustrative mitigation pathways (IMPs) consistent with limiting warming to 1.5°C with a high reliance on net negative emissions

(IMP-Neg) (“high overshoot”), high resource efﬁciency (IMP-LD), a focus on sustainable development (IMP-SP), renewables (IMP-Ren) and limiting warming to

2°C with less rapid mitigation initially followed by a gradual strengthening (IMP-GS). Positive and negative emissions for different IMPs are compared to GHG

emissions from the year 2019. Energy supply (including electricity) includes bioenergy with carbon dioxide capture and storage and direct air carbon dioxide

capture and storage. CO

emissions from land-use change and forestry can only be shown as a net number as many models do not report emissions and sinks

of this category separately. {Figure 3.6, 4.1} (Box SPM.1)

Overshoot: Exceeding a Warming Level and Returning

B.7 If warming exceeds a speciﬁed level such as 1.5°C, it could gradually be reduced again by

achieving and sustaining net negative global CO

emissions. This would require additional

deployment of carbon dioxide removal, compared to pathways without overshoot, leading

to greater feasibility and sustainability concerns. Overshoot entails adverse impacts, some

irreversible, and additional risks for human and natural systems, all growing with the

magnitude and duration of overshoot. (high conﬁdence) {3.1, 3.3, 3.4, Table 3.1, Figure 3.6}

B.7.1 Only a small number of the most ambitious global modelled pathways limit global warming to 1.5°C (>50%) by 2100

without exceeding this level temporarily. Achieving and sustaining net negative global CO

emissions, with annual rates

of CDR greater than residual CO

emissions, would gradually reduce the warming level again (high conﬁdence). Adverse

impacts that occur during this period of overshoot and cause additional warming via feedback mechanisms, such as

increased wildﬁres, mass mortality of trees, drying of peatlands, and permafrost thawing, weakening natural land

carbon sinks and increasing releases of GHGs would make the return more challenging (medium conﬁdence). {3.3.2,

3.3.4, Table 3.1, Figure 3.6} (Box SPM.1)

B.7.2 The higher the magnitude and the longer the duration of overshoot, the more ecosystems and societies are exposed

to greater and more widespread changes in climatic impact-drivers, increasing risks for many natural and human

systems. Compared to pathways without overshoot, societies would face higher risks to infrastructure, low-lying

coastal settlements, and associated livelihoods. Overshooting 1.5°C will result in irreversible adverse impacts on certain

ecosystems with low resilience, such as polar, mountain, and coastal ecosystems, impacted by ice-sheet melt, glacier

melt, or by accelerating and higher committed sea level rise. (high conﬁdence) {3.1.2, 3.3.4}

B.7.3 The larger the overshoot, the more net negative CO

emissions would be needed to return to 1.5°C by 2100. Transitioning

towards net zero CO

emissions faster and reducing non-CO

emissions such as methane more rapidly would limit

peak warming levels and reduce the requirement for net negative CO

emissions, thereby reducing feasibility and

sustainability concerns, and social and environmental risks associated with CDR deployment at large scales. (high

conﬁdence) {3.3.3, 3.3.4, 3.4.1, Table 3.1}

Summary for Policymakers

C. Responses in the Near Term

Urgency of Near-Term Integrated Climate Action

C.1 Climate change is a threat to human well-being and planetary health (very high conﬁdence).

There is a rapidly closing window of opportunity to secure a liveable and sustainable future for

all (very high conﬁdence). Climate resilient development integrates adaptation and mitigation

to advance sustainable development for all, and is enabled by increased international

cooperation including improved access to adequate ﬁnancial resources, particularly for

vulnerable regions, sectors and groups, and inclusive governance and coordinated policies

(high conﬁdence). The choices and actions implemented in this decade will have impacts now

and for thousands of years (high conﬁdence). {3.1, 3.3, 4.1, 4.2, 4.3, 4.4, 4.7, 4.8, 4.9, Figure 3.1,

Figure 3.3, Figure 4.2} (Figure SPM.1, Figure SPM.6)

C.1.1 Evidence of observed adverse impacts and related losses and damages, projected risks, levels and trends in vulnerability

and adaptation limits, demonstrate that worldwide climate resilient development action is more urgent than previously

assessed in AR5. Climate resilient development integrates adaptation and GHG mitigation to advance sustainable

development for all. Climate resilient development pathways have been constrained by past development, emissions

and climate change and are progressively constrained by every increment of warming, in particular beyond 1.5°C.

(very high conﬁdence) {3.4, 3.4.2, 4.1}

C.1.2 Government actions at sub-national, national and international levels, with civil society and the private sector, play a

crucial role in enabling and accelerating shifts in development pathways towards sustainability and climate resilient

development (very high conﬁdence). Climate resilient development is enabled when governments, civil society and

the private sector make inclusive development choices that prioritize risk reduction, equity and justice, and when

decision-making processes, ﬁnance and actions are integrated across governance levels, sectors, and timeframes (very

high conﬁdence). Enabling conditions are differentiated by national, regional and local circumstances and geographies,

according to capabilities, and include: political commitment and follow-through, coordinated policies, social and

international cooperation, ecosystem stewardship, inclusive governance, knowledge diversity, technological innovation,

monitoring and evaluation, and improved access to adequate ﬁnancial resources, especially for vulnerable regions,

sectors and communities (high conﬁdence). {3.4, 4.2, 4.4, 4.5, 4.7, 4.8} (Figure SPM.6)

C.1.3 Continued emissions will further affect all major climate system components, and many changes will be irreversible on

centennial to millennial time scales and become larger with increasing global warming. Without urgent, effective, and

equitable mitigation and adaptation actions, climate change increasingly threatens ecosystems, biodiversity, and the

livelihoods, health and well-being of current and future generations. (high conﬁdence) {3.1.3, 3.3.3, 3.4.1, Figure 3.4,

4.1, 4.2, 4.3, 4.4} (Figure SPM.1, Figure SPM.6)

Summary for Policymakers

Figure SPM.6: The illustrative development pathways (red to green) and associated outcomes (right panel) show that there is a rapidly narrowing window

of opportunity to secure a liveable and sustainable future for all. Climate resilient development is the process of implementing greenhouse gas mitigation and

adaptation measures to support sustainable development. Diverging pathways illustrate that interacting choices and actions made by diverse government,

private sector and civil society actors can advance climate resilient development, shift pathways towards sustainability, and enable lower emissions and

adaptation. Diverse knowledge and values include cultural values, Indigenous Knowledge, local knowledge, and scientiﬁc knowledge. Climatic and non-climatic

events, such as droughts, ﬂoods or pandemics, pose more severe shocks to pathways with lower climate resilient development (red to yellow) than to pathways

with higher climate resilient development (green). There are limits to adaptation and adaptive capacity for some human and natural systems at global warming

of 1.5°C, and with every increment of warming, losses and damages will increase. The development pathways taken by countries at all stages of economic

development impact GHG emissions and mitigation challenges and opportunities, which vary across countries and regions. Pathways and opportunities for

action are shaped by previous actions (or inactions and opportunities missed; dashed pathway) and enabling and constraining conditions (left panel), and

take place in the context of climate risks, adaptation limits and development gaps. The longer emissions reductions are delayed, the fewer effective adaptation

options. {Figure 4.2, 3.1, 3.2, 3.4, 4.2, 4.4, 4.5, 4.6, 4.9}

The Beneﬁts of Near-Term Action

C.2 Deep, rapid, and sustained mitigation and accelerated implementation of adaptation actions

in this decade would reduce projected losses and damages for humans and ecosystems

(very high conﬁdence), and deliver many co-beneﬁts, especially for air quality and health

(high conﬁdence). Delayed mitigation and adaptation action would lock in high-emissions

infrastructure, raise risks of stranded assets and cost-escalation, reduce feasibility, and

increase losses and damages (high conﬁdence). Near-term actions involve high up-front

investments and potentially disruptive changes that can be lessened by a range of enabling

policies (high conﬁdence). {2.1, 2.2, 3.1, 3.2, 3.3, 3.4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8}

C.2.1 Deep, rapid, and sustained mitigation and accelerated implementation of adaptation actions in this decade would

reduce future losses and damages related to climate change for humans and ecosystems (very high conﬁdence). As

adaptation options often have long implementation times, accelerated implementation of adaptation in this decade is

important to close adaptation gaps (high conﬁdence). Comprehensive, effective, and innovative responses integrating

adaptation and mitigation can harness synergies and reduce trade-offs between adaptation and mitigation (high

conﬁdence). {4.1, 4.2, 4.3}

Climate Resilient Development

Emissions reductions

Adaptation

Sustainable Development

Multiple interacting choices and actions can shift

development pathways towards sustainability

Sustainable Development

Goal (SDG) achievement

IPCC AR6

2030

Present

world

Past

conditions

There is a rapidly narrowing window of opportunity

to enable climate resilient development

Prospects for climate

resilient development will

be further limited if global

warming exceeds 1.5°C and

if progress towards the SDGs

is inadequate

Early action and enabling

conditions create future

opportunities for climate

resilient development

Past conditions

(emissions, climate

change, development)

have increased warming

and development gaps persist

Illustrative ‘shock’ that

disrupts development

Low emissions

System transitions

Transformation

Low climate risk

Equity and justice

SDG achievement

High emissions

Entrenched systems

Adaptation limits

Maladaptation

Increasing climate risk

Reduced options

for development

Ecosystem

degradation

Outcomes characterising

development pathways

Civil

society

Governments

Private

sector

Conditions that enable

individual and collective actions

• Inclusive governance

• Diverse knowledges and values

• Finance and innovation

• Integration across sectors

and time scales

• Ecosystem stewardship

• Synergies between climate

and development actions

• Behavioural change supported

by policy, infrastructure and

socio-cultural factors

Conditions that constrain

individual and collective actions

• Poverty, inequity and injustice

• Economic, institutional, social

and capacity barriers

• Siloed responses

• Lack of ﬁnance, and barriers

to ﬁnance and technology

• Tradeoffs with SDGs

2100

& beyond

Summary for Policymakers

C.2.2 Delayed mitigation action will further increase global warming and losses and damages will rise and additional human

and natural systems will reach adaptation limits. Challenges from delayed adaptation and mitigation actions include the

risk of cost escalation, lock-in of infrastructure, stranded assets, and reduced feasibility and effectiveness of adaptation

and mitigation options. Without rapid, deep and sustained mitigation and accelerated adaptation actions, losses

and damages will continue to increase, including projected adverse impacts in Africa, LDCs, SIDS, Central and South

America

, Asia and the Arctic, and will disproportionately affect the most vulnerable populations. (high conﬁdence)

{2.1.2, 3.1.2, 3.2, 3.3.1, 3.3.3, 4.1, 4.2, 4.3} (Figure SPM.3, Figure SPM.4)

C.2.3 Accelerated climate action can also provide co-beneﬁts (see also C.4) (high conﬁdence). Many mitigation actions would

have beneﬁts for health through lower air pollution, active mobility (e.g., walking, cycling), and shifts to sustainable

healthy diets (high conﬁdence). Strong, rapid and sustained reductions in methane emissions can limit near-term

warming and improve air quality by reducing global surface ozone (high conﬁdence). Adaptation can generate multiple

additional beneﬁts such as improving agricultural productivity, innovation, health and well-being, food security,

livelihood, and biodiversity conservation (very high conﬁdence). {4.2, 4.5.4, 4.5.5, 4.6}

C.2.4 Cost-beneﬁt analysis remains limited in its ability to represent all avoided damages from climate change (high

conﬁdence). The economic beneﬁts for human health from air quality improvement arising from mitigation action can

be of the same order of magnitude as mitigation costs, and potentially even larger (medium conﬁdence). Even without

accounting for all the beneﬁts of avoiding potential damages, the global economic and social beneﬁt of limiting global

warming to 2°C exceeds the cost of mitigation in most of the assessed literature (medium conﬁdence)

. More rapid

climate change mitigation, with emissions peaking earlier, increases co-beneﬁts and reduces feasibility risks and costs

in the long-term, but requires higher up-front investments (high conﬁdence). {3.4.1, 4.2}

C.2.5 Ambitious mitigation pathways imply large and sometimes disruptive changes in existing economic structures, with

signiﬁcant distributional consequences within and between countries. To accelerate climate action, the adverse

consequences of these changes can be moderated by ﬁscal, ﬁnancial, institutional and regulatory reforms and by

integrating climate actions with macroeconomic policies through (i) economy-wide packages, consistent with national

circumstances, supporting sustainable low-emission growth paths; (ii) climate resilient safety nets and social protection;

and (iii) improved access to ﬁnance for low-emissions infrastructure and technologies, especially in developing countries.

(high conﬁdence) {4.2, 4.4, 4.7, 4.8.1}

The southern part of Mexico is included in the climatic subregion South Central America (SCA) for WGI. Mexico is assessed as part of North America for

WGII. The climate change literature for the SCA region occasionally includes Mexico, and in those cases WGII assessment makes reference to Latin America.

Mexico is considered part of Latin America and the Caribbean for WGIII.

The evidence is too limited to make a similar robust conclusion for limiting warming to 1.5°C. Limiting global warming to 1.5°C instead of 2°C would

increase the costs of mitigation, but also increase the beneﬁts in terms of reduced impacts and related risks, and reduced adaptation needs (high

conﬁdence).

Summary for Policymakers

Figure SPM.7: Multiple Opportunities for scaling up climate action. Panel (a) presents selected mitigation and adaptation options across different

systems. The left-hand side of panel a shows climate responses and adaptation options assessed for their multidimensional feasibility at global scale, in the near

term and up to 1.5°C global warming. As literature above 1.5°C is limited, feasibility at higher levels of warming may change, which is currently not possible

to assess robustly. The term response is used here in addition to adaptation because some responses, such as migration, relocation and resettlement may or

may not be considered to be adaptation. Forest based adaptation includes sustainable forest management, forest conservation and restoration, reforestation

There are multiple opportunities for scaling up climate action

Costs are lower than the reference

0–20 (USD per tCO

-eq)

20–50 (USD per tCO

-eq)

50–100 (USD per tCO

-eq)

100–200 (USD per tCO

-eq)

Cost not allocated due to high

variability or lack of data

Net lifetime cost of options:

Feasibility level and synergies

with mitigation

Insufﬁcient evidence

Conﬁdence level in potential feasibility

and in synergies with mitigation

MediumHigh Low

a) Feasibility of climate responses and adaptation, and potential of mitigation options in the near term

High Medium Low

Synergies

with

mitigation

not

assessed

0 1 2 3 4 5

Potential contribution to

net emission reduction, 2030

Carbon capture with

utilisation (CCU) and CCS

Material efﬁciency

Enhanced recycling

Construction materials substitution

Energy efﬁciency

Wind

Solar

Reduce methane and N

O in agriculture

Reduce food loss and food waste

Geothermal and hydropower

Carbon sequestration in agriculture

Reduce conversion of natural ecosystems

Nuclear

Reduce methane from coal, oil and gas

Bioelectricity (includes BECCS)

Fossil Carbon Capture and Storage (CCS)

Ecosystem restoration,

afforestation, reforestation

Fuel switching

Reduce emission of ﬂuorinated gas

Reduce methane from

waste/wastewater

Improved sustainable forest management

Climate responses and

adaptation options

Mitigation options

GtCO

-eq/yr

Enhanced health services

(e.g. WASH, nutrition and diets)

Green infrastructure and

ecosystem services

Sustainable land use and urban planning

Sustainable urban water management

Climate services, including

Early Warning Systems

Livelihood diversiﬁcation

Disaster risk management

Social safety nets

Risk spreading and sharing

Planned relocation and resettlement

Human migration

Agroforestry

Sustainable aquaculture and ﬁsheries

Efﬁcient livestock systems

Biodiversity management and

ecosystem connectivity

Integrated coastal zone management

Water use efﬁciency and water

resource management

Improved cropland management

Coastal defence and hardening

Forest-based adaptation

Resilient power systems

Energy reliability (e.g.

diversiﬁcation, access, stability)

Improve water use efﬁciency

Potential

feasibility

up to 1.5°C

ENERGY SUPPLY

LAND, WATER, FOOD

HEALTH

SETTLEMENTS

AND

INFRASTRUCTURE

SOCIETY, LIVELIHOOD

AND ECONOMY

INDUSTRY AND WASTE

100

Electricity

Land transport

Buildings

Industry

Food

67%

66%

29%

44%

73% reduction (before

additional electriﬁcation)

Additional electriﬁcation (+60%)

GtCO

-eq/yr

GtCO

/yr

Key

Total emissions (2050)

Percentage of possible reduction

Demand-side mitigation potential

Potential range

Efﬁcient lighting, appliances

and equipment

Efﬁcient shipping and aviation

Avoid demand for energy services

Efﬁcient buildings

Electric vehicles

Public transport and bicycling

Biofuels for transport

Onsite renewables

Fuel efﬁcient vehicles

Shift to sustainable healthy diets

options costing 100 USD tCO

-eq

-1

less could reduce global emissions by

at least half of the 2019 level by 2030

b) Potential of demand-side

mitigation options by 2050

the range of GHG emissions

reduction potential is 40-70%

in these end-use sectors

Summary for Policymakers

and afforestation. WASH refers to water, sanitation and hygiene. Six feasibility dimensions (economic, technological, institutional, social, environmental and

geophysical) were used to calculate the potential feasibility of climate responses and adaptation options, along with their synergies with mitigation. For

potential feasibility and feasibility dimensions, the ﬁgure shows high, medium, or low feasibility. Synergies with mitigation are identiﬁed as high, medium, and

low. The right-hand side of Panel a provides an overview of selected mitigation options and their estimated costs and potentials in 2030. Costs are net lifetime

discounted monetary costs of avoided GHG emissions calculated relative to a reference technology. Relative potentials and costs will vary by place, context and

time and in the longer term compared to 2030. The potential (horizontal axis) is the net GHG emission reduction (sum of reduced emissions and/or enhanced

sinks) broken down into cost categories (coloured bar segments) relative to an emission baseline consisting of current policy (around 2019) reference scenarios

from the AR6 scenarios database. The potentials are assessed independently for each option and are not additive. Health system mitigation options are included

mostly in settlement and infrastructure (e.g., efﬁcient healthcare buildings) and cannot be identiﬁed separately. Fuel switching in industry refers to switching

to electricity, hydrogen, bioenergy and natural gas. Gradual colour transitions indicate uncertain breakdown into cost categories due to uncertainty or heavy

context dependency. The uncertainty in the total potential is typically 25–50%. Panel (b) displays the indicative potential of demand-side mitigation options

for 2050. Potentials are estimated based on approximately 500 bottom-up studies representing all global regions. The baseline (white bar) is provided by the

sectoral mean GHG emissions in 2050 of the two scenarios (IEA-STEPS and IP_ModAct) consistent with policies announced by national governments until 2020.

The green arrow represents the demand-side emissions reductions potentials. The range in potential is shown by a line connecting dots displaying the highest

and the lowest potentials reported in the literature. Food shows demand-side potential of socio-cultural factors and infrastructure use, and changes in land-use

patterns enabled by change in food demand. Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end-use

sectors (buildings, land transport, food) by 40–70% by 2050 compared to baseline scenarios, while some regions and socioeconomic groups require additional

energy and resources. The last row shows how demand-side mitigation options in other sectors can inﬂuence overall electricity demand. The dark grey bar shows

the projected increase in electricity demand above the 2050 baseline due to increasing electriﬁcation in the other sectors. Based on a bottom-up assessment,

this projected increase in electricity demand can be avoided through demand-side mitigation options in the domains of infrastructure use and socio-cultural

factors that inﬂuence electricity usage in industry, land transport, and buildings (green arrow). {Figure 4.4}

Mitigation and Adaptation Options across Systems

C.3 Rapid and far-reaching transitions across all sectors and systems are necessary to achieve

deep and sustained emissions reductions and secure a liveable and sustainable future for all.

These system transitions involve a signiﬁcant upscaling of a wide portfolio of mitigation and

adaptation options. Feasible, effective, and low-cost options for mitigation and adaptation

are already available, with differences across systems and regions. (high conﬁdence) {4.1, 4.5,

4.6} (Figure SPM.7)

C.3.1 The systemic change required to achieve rapid and deep emissions reductions and transformative adaptation to climate

change is unprecedented in terms of scale, but not necessarily in terms of speed (medium conﬁdence). Systems transitions

include: deployment of low- or zero-emission technologies; reducing and changing demand through infrastructure

design and access, socio-cultural and behavioural changes, and increased technological efﬁciency and adoption; social

protection, climate services or other services; and protecting and restoring ecosystems (high conﬁdence). Feasible,

effective, and low-cost options for mitigation and adaptation are already available (high conﬁdence). The availability,

feasibility and potential of mitigation and adaptation options in the near term differs across systems and regions (very

high conﬁdence). {4.1, 4.5.1 to 4.5.6} (Figure SPM.7)

Energy Systems

C.3.2 Net zero CO

energy systems entail: a substantial reduction in overall fossil fuel use, minimal use of unabated fossil

fuels

, and use of carbon capture and storage in the remaining fossil fuel systems; electricity systems that emit no

net CO

; widespread electriﬁcation; alternative energy carriers in applications less amenable to electriﬁcation; energy

conservation and efﬁciency; and greater integration across the energy system (high conﬁdence). Large contributions

to emissions reductions with costs less than USD 20 tCO

-eq

-1

come from solar and wind energy, energy efﬁciency

improvements, and methane emissions reductions (coal mining, oil and gas, waste) (medium conﬁdence). There are

feasible adaptation options that support infrastructure resilience, reliable power systems and efﬁcient water use for

existing and new energy generation systems (very high conﬁdence). Energy generation diversiﬁcation (e.g., via wind,

solar, small scale hydropower) and demand-side management (e.g., storage and energy efﬁciency improvements) can

increase energy reliability and reduce vulnerabilities to climate change (high conﬁdence). Climate responsive energy

markets, updated design standards on energy assets according to current and projected climate change, smart-grid

technologies, robust transmission systems and improved capacity to respond to supply deﬁcits have high feasibility in

the medium to long term, with mitigation co-beneﬁts (very high conﬁdence). {4.5.1} (Figure SPM.7)

In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce the amount of GHG emitted

throughout the life cycle; for example, capturing 90% or more CO

from power plants, or 50–80% of fugitive methane emissions from energy supply.

Summary for Policymakers

Industry and Transport

C.3.3 Reducing industry GHG emissions entails coordinated action throughout value chains to promote all mitigation

options, including demand management, energy and materials efﬁciency, circular material ﬂows, as well as abatement

technologies and transformational changes in production processes (high conﬁdence). In transport, sustainable

biofuels, low-emissions hydrogen, and derivatives (including ammonia and synthetic fuels) can support mitigation of

emissions from shipping, aviation, and heavy-duty land transport but require production process improvements

and cost reductions (medium conﬁdence). Sustainable biofuels can offer additional mitigation beneﬁts in land-based

transport in the short and medium term (medium conﬁdence). Electric vehicles powered by low-GHG emissions

electricity have large potential to reduce land-based transport GHG emissions, on a life cycle basis (high conﬁdence).

Advances in battery technologies could facilitate the electriﬁcation of heavy-duty trucks and compliment conventional

electric rail systems (medium conﬁdence). The environmental footprint of battery production and growing concerns

about critical minerals can be addressed by material and supply diversiﬁcation strategies, energy and material efﬁciency

improvements, and circular material ﬂows (medium conﬁdence). {4.5.2, 4.5.3} (Figure SPM.7)

Cities, Settlements and Infrastructure

C.3.4 Urban systems are critical for achieving deep emissions reductions and advancing climate resilient development (high

conﬁdence). Key adaptation and mitigation elements in cities include considering climate change impacts and risks

(e.g., through climate services) in the design and planning of settlements and infrastructure; land use planning to

achieve compact urban form, co-location of jobs and housing; supporting public transport and active mobility (e.g.,

walking and cycling); the efﬁcient design, construction, retroﬁt, and use of buildings; reducing and changing energy

and material consumption; sufﬁciency

; material substitution; and electriﬁcation in combination with low emissions

sources (high conﬁdence). Urban transitions that offer beneﬁts for mitigation, adaptation, human health and well-

being, ecosystem services, and vulnerability reduction for low-income communities are fostered by inclusive long-term

planning that takes an integrated approach to physical, natural and social infrastructure (high conﬁdence). Green/

natural and blue infrastructure supports carbon uptake and storage and either singly or when combined with grey

infrastructure can reduce energy use and risk from extreme events such as heatwaves, ﬂooding, heavy precipitation and

droughts, while generating co-beneﬁts for health, well-being and livelihoods (medium conﬁdence). {4.5.3}

Land, Ocean, Food, and Water

C.3.5 Many agriculture, forestry, and other land use (AFOLU) options provide adaptation and mitigation beneﬁts that could

be upscaled in the near term across most regions. Conservation, improved management, and restoration of forests

and other ecosystems offer the largest share of economic mitigation potential, with reduced deforestation in tropical

regions having the highest total mitigation potential. Ecosystem restoration, reforestation, and afforestation can lead to

trade-offs due to competing demands on land. Minimizing trade-offs requires integrated approaches to meet multiple

objectives including food security. Demand-side measures (shifting to sustainable healthy diets

and reducing food loss/

waste) and sustainable agricultural intensiﬁcation can reduce ecosystem conversion, and methane and nitrous oxide

emissions, and free up land for reforestation and ecosystem restoration. Sustainably sourced agricultural and forest

products, including long-lived wood products, can be used instead of more GHG-intensive products in other sectors.

Effective adaptation options include cultivar improvements, agroforestry, community-based adaptation, farm and

landscape diversiﬁcation, and urban agriculture. These AFOLU response options require integration of biophysical,

socioeconomic and other enabling factors. Some options, such as conservation of high-carbon ecosystems (e.g., peatlands,

wetlands, rangelands, mangroves and forests), deliver immediate beneﬁts, while others, such as restoration of high-carbon

ecosystems, take decades to deliver measurable results. (high conﬁdence) {4.5.4} (Figure SPM.7)

C.3.6 Maintaining the resilience of biodiversity and ecosystem services at a global scale depends on effective and equitable

conservation of approximately 30% to 50% of Earth’s land, freshwater and ocean areas, including currently near-

natural ecosystems (high conﬁdence). Conservation, protection and restoration of terrestrial, freshwater, coastal and

A set of measures and daily practices that avoid demand for energy, materials, land, and water while delivering human well-being for all within planetary

boundaries. {4.5.3}

‘Sustainable healthy diets’ promote all dimensions of individuals’ health and well-being; have low environmental pressure and impact; are accessible,

affordable, safe and equitable; and are culturally acceptable, as described in FAO and WHO. The related concept of ‘balanced diets’ refers to diets that

feature plant-based foods, such as those based on coarse grains, legumes, fruits and vegetables, nuts and seeds, and animal-sourced food produced in

resilient, sustainable and low-GHG emission systems, as described in SRCCL.

Summary for Policymakers

ocean ecosystems, together with targeted management to adapt to unavoidable impacts of climate change reduces

the vulnerability of biodiversity and ecosystem services to climate change (high conﬁdence), reduces coastal erosion

and ﬂooding (high conﬁdence), and could increase carbon uptake and storage if global warming is limited (medium

conﬁdence). Rebuilding overexploited or depleted ﬁsheries reduces negative climate change impacts on ﬁsheries

(medium conﬁdence) and supports food security, biodiversity, human health and well-being (high conﬁdence). Land

restoration contributes to climate change mitigation and adaptation with synergies via enhanced ecosystem services

and with economically positive returns and co-beneﬁts for poverty reduction and improved livelihoods (high conﬁdence).

Cooperation, and inclusive decision making, with Indigenous Peoples and local communities, as well as recognition of

inherent rights of Indigenous Peoples, is integral to successful adaptation and mitigation across forests and other

ecosystems (high conﬁdence). {4.5.4, 4.6} (Figure SPM.7)

Health and Nutrition

C.3.7 Human health will beneﬁt from integrated mitigation and adaptation options that mainstream health into food,

infrastructure, social protection, and water policies (very high conﬁdence). Effective adaptation options exist to help

protect human health and well-being, including: strengthening public health programs related to climate-sensitive

diseases, increasing health systems resilience, improving ecosystem health, improving access to potable water,

reducing exposure of water and sanitation systems to ﬂooding, improving surveillance and early warning systems,

vaccine development (very high conﬁdence), improving access to mental healthcare, and Heat Health Action Plans that

include early warning and response systems (high conﬁdence). Adaptation strategies which reduce food loss and waste

or support balanced, sustainable healthy diets contribute to nutrition, health, biodiversity and other environmental

beneﬁts (high conﬁdence). {4.5.5} (Figure SPM.7)

Society, Livelihoods, and Economies

C.3.8 Policy mixes that include weather and health insurance, social protection and adaptive social safety nets, contingent

ﬁnance and reserve funds, and universal access to early warning systems combined with effective contingency plans, can

reduce vulnerability and exposure of human systems. Disaster risk management, early warning systems, climate services

and risk spreading and sharing approaches have broad applicability across sectors. Increasing education including

capacity building, climate literacy, and information provided through climate services and community approaches can

facilitate heightened risk perception and accelerate behavioural changes and planning. (high conﬁdence) {4.5.6}

Synergies and Trade-Offs with Sustainable Development

C.4 Accelerated and equitable action in mitigating and adapting to climate change impacts is

critical to sustainable development. Mitigation and adaptation actions have more synergies

than trade-offs with Sustainable Development Goals. Synergies and trade-offs depend on

context and scale of implementation. (high conﬁdence) {3.4, 4.2, 4.4, 4.5, 4.6, 4.9, Figure 4.5}

C.4.1 Mitigation efforts embedded within the wider development context can increase the pace, depth and breadth of emission

reductions (medium conﬁdence). Countries at all stages of economic development seek to improve the well-being of

people, and their development priorities reﬂect different starting points and contexts. Different contexts include but

are not limited to social, economic, environmental, cultural, political circumstances, resource endowment, capabilities,

international environment, and prior development (high conﬁdence). In regions with high dependency on fossil fuels for,

among other things, revenue and employment generation, mitigating risk for sustainable development requires policies

that promote economic and energy sector diversiﬁcation and considerations of just transitions principles, processes

and practices (high conﬁdence). Eradicating extreme poverty, energy poverty, and providing decent living standards in

low-emitting countries / regions in the context of achieving sustainable development objectives, in the near term, can

be achieved without signiﬁcant global emissions growth (high conﬁdence). {4.4, 4.6, Annex I: Glossary}

C.4.2 Many mitigation and adaptation actions have multiple synergies with Sustainable Development Goals (SDGs) and

sustainable development generally, but some actions can also have trade-offs. Potential synergies with SDGs exceed

potential trade-offs; synergies and trade-offs depend on the pace and magnitude of change and the development

context including inequalities with consideration of climate justice. Trade-offs can be evaluated and minimised by

giving emphasis to capacity building, ﬁnance, governance, technology transfer, investments, development, context

speciﬁc gender-based and other social equity considerations with meaningful participation of Indigenous Peoples, local

communities and vulnerable populations. (high conﬁdence) {3.4.1, 4.6, Figure 4.5, 4.9}

Summary for Policymakers

C.4.3 Implementing both mitigation and adaptation actions together and taking trade-offs into account supports co-beneﬁts

and synergies for human health and well-being. For example, improved access to clean energy sources and technologies

generates health beneﬁts especially for women and children; electriﬁcation combined with low-GHG energy, and shifts

to active mobility and public transport can enhance air quality, health, employment, and can elicit energy security and

deliver equity. (high conﬁdence) {4.2, 4.5.3, 4.5.5, 4.6, 4.9}

Equity and Inclusion

C.5 Prioritising equity, climate justice, social justice, inclusion and just transition processes can

enable adaptation and ambitious mitigation actions and climate resilient development.

Adaptation outcomes are enhanced by increased support to regions and people with the

highest vulnerability to climatic hazards. Integrating climate adaptation into social protection

programs improves resilience. Many options are available for reducing emission-intensive

consumption, including through behavioural and lifestyle changes, with co-beneﬁts for

societal well-being. (high conﬁdence) {4.4, 4.5}

C.5.1 Equity remains a central element in the UN climate regime, notwithstanding shifts in differentiation between states

over time and challenges in assessing fair shares. Ambitious mitigation pathways imply large and sometimes disruptive

changes in economic structure, with signiﬁcant distributional consequences, within and between countries. Distributional

consequences within and between countries include shifting of income and employment during the transition from

high- to low-emissions activities. (high conﬁdence) {4.4}

C.5.2 Adaptation and mitigation actions that prioritise equity, social justice, climate justice, rights-based approaches, and

inclusivity, lead to more sustainable outcomes, reduce trade-offs, support transformative change and advance climate

resilient development. Redistributive policies across sectors and regions that shield the poor and vulnerable, social

safety nets, equity, inclusion and just transitions, at all scales can enable deeper societal ambitions and resolve trade-

offs with sustainable development goals. Attention to equity and broad and meaningful participation of all relevant

actors in decision making at all scales can build social trust which builds on equitable sharing of beneﬁts and burdens

of mitigation that deepen and widen support for transformative changes. (high conﬁdence) {4.4}

C.5.3 Regions and people (3.3 to 3.6 billion in number) with considerable development constraints have high vulnerability to

climatic hazards (see A.2.2). Adaptation outcomes for the most vulnerable within and across countries and regions are

enhanced through approaches focusing on equity, inclusivity and rights-based approaches. Vulnerability is exacerbated

by inequity and marginalisation linked to e.g., gender, ethnicity, low incomes, informal settlements, disability, age,

and historical and ongoing patterns of inequity such as colonialism, especially for many Indigenous Peoples and local

communities. Integrating climate adaptation into social protection programs, including cash transfers and public works

programs, is highly feasible and increases resilience to climate change, especially when supported by basic services

and infrastructure. The greatest gains in well-being in urban areas can be achieved by prioritising access to ﬁnance to

reduce climate risk for low-income and marginalised communities including people living in informal settlements. (high

conﬁdence) {4.4, 4.5.3, 4.5.5, 4.5.6}

C.5.4 The design of regulatory instruments and economic instruments and consumption-based approaches, can advance equity.

Individuals with high socio-economic status contribute disproportionately to emissions, and have the highest potential

for emissions reductions. Many options are available for reducing emission-intensive consumption while improving

societal well-being. Socio-cultural options, behaviour and lifestyle changes supported by policies, infrastructure, and

technology can help end-users shift to low-emissions-intensive consumption, with multiple co-beneﬁts. A substantial

share of the population in low-emitting countries lack access to modern energy services. Technology development,

transfer, capacity building and ﬁnancing can support developing countries / regions leapfrogging or transitioning to

low-emissions transport systems thereby providing multiple co-beneﬁts. Climate resilient development is advanced

when actors work in equitable, just and inclusive ways to reconcile divergent interests, values and worldviews, toward

equitable and just outcomes. (high conﬁdence) {2.1, 4.4}

Summary for Policymakers

Governance and Policies

C.6 Effective climate action is enabled by political commitment, well-aligned multilevel

governance, institutional frameworks, laws, policies and strategies and enhanced access

to ﬁnance and technology. Clear goals, coordination across multiple policy domains, and

inclusive governance processes facilitate effective climate action. Regulatory and economic

instruments can support deep emissions reductions and climate resilience if scaled up and

applied widely. Climate resilient development beneﬁts from drawing on diverse knowledge.

(high conﬁdence) {2.2, 4.4, 4.5, 4.7}

C.6.1 Effective climate governance enables mitigation and adaptation. Effective governance provides overall direction on

setting targets and priorities and mainstreaming climate action across policy domains and levels, based on national

circumstances and in the context of international cooperation. It enhances monitoring and evaluation and regulatory

certainty, prioritising inclusive, transparent and equitable decision-making, and improves access to ﬁnance and

technology (see C.7). (high conﬁdence) {2.2.2, 4.7}

C.6.2 Effective local, municipal, national and subnational institutions build consensus for climate action among diverse

interests, enable coordination and inform strategy setting but require adequate institutional capacity. Policy support is

inﬂuenced by actors in civil society, including businesses, youth, women, labour, media, Indigenous Peoples, and local

communities. Effectiveness is enhanced by political commitment and partnerships between different groups in society.

(high conﬁdence) {2.2, 4.7}

C.6.3 Effective multilevel governance for mitigation, adaptation, risk management, and climate resilient development is

enabled by inclusive decision processes that prioritise equity and justice in planning and implementation, allocation of

appropriate resources, institutional review, and monitoring and evaluation. Vulnerabilities and climate risks are often

reduced through carefully designed and implemented laws, policies, participatory processes, and interventions that

address context speciﬁc inequities such as those based on gender, ethnicity, disability, age, location and income. (high

conﬁdence) {4.4, 4.7}

C.6.4 Regulatory and economic instruments could support deep emissions reductions if scaled up and applied more widely

(high conﬁdence). Scaling up and enhancing the use of regulatory instruments can improve mitigation outcomes in

sectoral applications, consistent with national circumstances (high conﬁdence). Where implemented, carbon pricing

instruments have incentivized low-cost emissions reduction measures but have been less effective, on their own and

at prevailing prices during the assessment period, to promote higher-cost measures necessary for further reductions

(medium conﬁdence). Equity and distributional impacts of such carbon pricing instruments, e.g., carbon taxes and

emissions trading, can be addressed by using revenue to support low-income households, among other approaches.

Removing fossil fuel subsidies would reduce emissions

and yield beneﬁts such as improved public revenue,

macroeconomic and sustainability performance; subsidy removal can have adverse distributional impacts, especially

on the most economically vulnerable groups which, in some cases can be mitigated by measures such as redistributing

revenue saved, all of which depend on national circumstances (high conﬁdence). Economy-wide policy packages, such

as public spending commitments and pricing reforms, can meet short-term economic goals while reducing emissions and

shifting development pathways towards sustainability (medium conﬁdence). Effective policy packages would be comprehensive,

consistent, balanced across objectives, and tailored to national circumstances (high conﬁdence). {2.2.2, 4.7}

C.6.5 Drawing on diverse knowledges and cultural values, meaningful participation and inclusive engagement processes—

including Indigenous Knowledge, local knowledge, and scientiﬁc knowledge—facilitates climate resilient development,

builds capacity and allows locally appropriate and socially acceptable solutions. (high conﬁdence) {4.4, 4.5.6, 4.7}

Fossil fuel subsidy removal is projected by various studies to reduce global CO

emission by 1 to 4%, and GHG emissions by up to 10% by 2030, varying

across regions (medium conﬁdence).

Summary for Policymakers

Finance, Technology and International Cooperation

C.7 Finance, technology and international cooperation are critical enablers for accelerated climate

action. If climate goals are to be achieved, both adaptation and mitigation ﬁnancing would

need to increase many-fold. There is sufﬁcient global capital to close the global investment

gaps but there are barriers to redirect capital to climate action. Enhancing technology

innovation systems is key to accelerate the widespread adoption of technologies and

practices. Enhancing international cooperation is possible through multiple channels. (high

conﬁdence) {2.3, 4.8}

C.7.1 Improved availability of and access to ﬁnance

would enable accelerated climate action (very high conﬁdence).

Addressing needs and gaps and broadening equitable access to domestic and international ﬁnance, when combined

with other supportive actions, can act as a catalyst for accelerating adaptation and mitigation, and enabling climate

resilient development (high conﬁdence). If climate goals are to be achieved, and to address rising risks and accelerate

investments in emissions reductions, both adaptation and mitigation ﬁnance would need to increase many-fold (high

conﬁdence). {4.8.1}

C.7.2 Increased access to ﬁnance can build capacity and address soft limits to adaptation and avert rising risks, especially for

developing countries, vulnerable groups, regions and sectors (high conﬁdence). Public ﬁnance is an important enabler

of adaptation and mitigation, and can also leverage private ﬁnance (high conﬁdence). Average annual modelled

mitigation investment requirements for 2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a factor of

three to six greater than current levels

, and total mitigation investments (public, private, domestic and international)

would need to increase across all sectors and regions (medium conﬁdence). Even if extensive global mitigation efforts

are implemented, there will be a need for ﬁnancial, technical, and human resources for adaptation (high conﬁdence).

{4.3, 4.8.1}

C.7.3 There is sufﬁcient global capital and liquidity to close global investment gaps, given the size of the global ﬁnancial

system, but there are barriers to redirect capital to climate action both within and outside the global ﬁnancial sector and

in the context of economic vulnerabilities and indebtedness facing developing countries. Reducing ﬁnancing barriers for

scaling up ﬁnancial ﬂows would require clear signalling and support by governments, including a stronger alignment

of public ﬁnances in order to lower real and perceived regulatory, cost and market barriers and risks and improving

the risk-return proﬁle of investments. At the same time, depending on national contexts, ﬁnancial actors, including

investors, ﬁnancial intermediaries, central banks and ﬁnancial regulators can shift the systemic underpricing of climate-

related risks, and reduce sectoral and regional mismatches between available capital and investment needs. (high

conﬁdence) {4.8.1}

C.7.4 Tracked ﬁnancial ﬂows fall short of the levels needed for adaptation and to achieve mitigation goals across all sectors

and regions. These gaps create many opportunities and the challenge of closing gaps is largest in developing countries.

Accelerated ﬁnancial support for developing countries from developed countries and other sources is a critical enabler

to enhance adaptation and mitigation actions and address inequities in access to ﬁnance, including its costs, terms

and conditions, and economic vulnerability to climate change for developing countries. Scaled-up public grants for

mitigation and adaptation funding for vulnerable regions, especially in Sub-Saharan Africa, would be cost-effective and

have high social returns in terms of access to basic energy. Options for scaling up mitigation in developing countries

include: increased levels of public ﬁnance and publicly mobilised private ﬁnance ﬂows from developed to developing

countries in the context of the USD 100 billion-a-year goal; increased use of public guarantees to reduce risks and

leverage private ﬂows at lower cost; local capital markets development; and building greater trust in international

cooperation processes. A coordinated effort to make the post-pandemic recovery sustainable over the longer-term

can accelerate climate action, including in developing regions and countries facing high debt costs, debt distress and

macroeconomic uncertainty. (high conﬁdence) {4.8.1}

C.7.5 Enhancing technology innovation systems can provide opportunities to lower emissions growth, create social and

environmental co-beneﬁts, and achieve other SDGs. Policy packages tailored to national contexts and technological

characteristics have been effective in supporting low-emission innovation and technology diffusion. Public policies can

Finance originates from diverse sources: public or private, local, national or international, bilateral or multilateral, and alternative sources. It can take the

form of grants, technical assistance, loans (concessional and non-concessional), bonds, equity, risk insurance and ﬁnancial guarantees (of different types).

These estimates rely on scenario assumptions.

Summary for Policymakers

support training and R&D, complemented by both regulatory and market-based instruments that create incentives and

market opportunities. Technological innovation can have trade-offs such as new and greater environmental impacts,

social inequalities, overdependence on foreign knowledge and providers, distributional impacts and rebound effects

requiring appropriate governance and policies to enhance potential and reduce trade-offs. Innovation and adoption of

low-emission technologies lags in most developing countries, particularly least developed ones, due in part to weaker

enabling conditions, including limited ﬁnance, technology development and transfer, and capacity building. (high

conﬁdence) {4.8.3}

C.7.6 International cooperation is a critical enabler for achieving ambitious climate change mitigation, adaptation, and climate

resilient development (high conﬁdence). Climate resilient development is enabled by increased international cooperation

including mobilising and enhancing access to ﬁnance, particularly for developing countries, vulnerable regions, sectors

and groups and aligning ﬁnance ﬂows for climate action to be consistent with ambition levels and funding needs (high

conﬁdence). Enhancing international cooperation on ﬁnance, technology and capacity building can enable greater

ambition and can act as a catalyst for accelerating mitigation and adaptation, and shifting development pathways

towards sustainability (high conﬁdence). This includes support to NDCs and accelerating technology development and

deployment (high conﬁdence). Transnational partnerships can stimulate policy development, technology diffusion,

adaptation and mitigation, though uncertainties remain over their costs, feasibility and effectiveness (medium

conﬁdence). International environmental and sectoral agreements, institutions and initiatives are helping, and in some

cases may help, to stimulate low GHG emissions investments and reduce emissions (medium conﬁdence). {2.2.2, 4.8.2}

Leading to lower net emission reductions or even emission increases.

Climate Change 2023

Synthesis Report

IPCC, 2023: Sections. In: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth

Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC,

Geneva, Switzerland, pp. 35-115, doi: 10.59327/IPCC/AR6-9789291691647

These Sections should be cited as:

Section 1

Introduction

Section 1

This Synthesis Report (SYR) of the IPCC Sixth Assessment Report (AR6)

summarises the state of knowledge of climate change, its widespread

impacts and risks, and climate change mitigation and adaptation, based

on the peer-reviewed scientiﬁc, technical and socio-economic literature

since the publication of the IPCC’s Fifth Assessment Report (AR5) in

2014.

The assessment is undertaken within the context of the evolving

international landscape, in particular, developments in the UN

Framework Convention on Climate Change (UNFCCC) process,

including the outcomes of the Kyoto Protocol and the adoption of the

Paris Agreement. It reﬂects the increasing diversity of those involved in

climate action.

This report integrates the main ﬁndings of the AR6 Working Group

reports

and the three AR6 Special Reports

. It recognizes the

interdependence of climate, ecosystems and biodiversity, and human

societies; the value of diverse forms of knowledge; and the close

linkages between climate change adaptation, mitigation, ecosystem

health, human well-being and sustainable development. Building on

multiple analytical frameworks, including those from the physical and

social sciences, this report identiﬁes opportunities for transformative

action which are effective, feasible, just and equitable using concepts

of systems transitions and resilient development pathways

. Different

regional classiﬁcation schemes

are used for physical, social and

economic aspects, reﬂecting the underlying literature.

After this introduction, Section 2, ‘Current Status and Trends’, opens

with the assessment of observational evidence for our changing

climate, historical and current drivers of human-induced climate

change, and its impacts. It assesses the current implementation of

adaptation and mitigation response options. Section 3, ‘Long-Term

Climate and Development Futures’, provides a long-term assessment of

climate change to 2100 and beyond in a broad range of socio-economic

The three Working Group contributions to AR6 are: Climate Change 2021: The Physical Science Basis; Climate Change 2022: Impacts, Adaptation and Vulnerability; and Climate

Change 2022: Mitigation of Climate Change, respectively. Their assessments cover scientiﬁc literature accepted for publication respectively by 31 January 2021, 1 September

2021 and 11 October 2021.

The three Special Reports are : Global Warming of 1.5°C (2018): an IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related

global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate

poverty (SR1.5); Climate Change and Land (2019): an IPCC Special Report on climate change, desertiﬁcation, land degradation, sustainable land management, food security, and

greenhouse gas ﬂuxes in terrestrial ecosystems (SRCCL); and The Ocean and Cryosphere in a Changing Climate (2019) (SROCC). The Special Reports cover scientiﬁc literature

accepted for publication respectively by 15 May 2018, 7 April 2019 and 15 May 2019.

The Glossary (Annex I) includes deﬁnitions of these, and other terms and concepts used in this report drawn from the AR6 joint Working Group Glossary.

Depending on the climate information context, geographical regions in AR6 may refer to larger areas, such as sub-continents and oceanic regions, or to typological regions, such

as monsoon regions, coastlines, mountain ranges or cities. A new set of standard AR6 WGI reference land and ocean regions have been deﬁned. WGIII allocates countries to

geographical regions, based on the UN Statistics Division Classiﬁcation {WGI 1.4.5, WGI 10.1, WGI 11.9, WGI 12.1–12.4, WGI Atlas.1.3.3–1.3.4}.

Each ﬁnding is grounded in an evaluation of underlying evidence and agreement. A level of conﬁdence is expressed using ﬁve qualiﬁers: very low, low, medium, high and very

high, and typeset in italics, for example, medium conﬁdence. The following terms have been used to indicate the assessed likelihood of an outcome or result: virtually certain

99–100% probability; very likely 90–100%; likely 66–100%; more likely than not >50-100%; about as likely as not 33–66%; unlikely 0–33%; very unlikely 0–10%; and

exceptionally unlikely 0–1%. Additional terms (extremely likely 95–100% and extremely unlikely 0–5%) are also used when appropriate. Assessed likelihood also is typeset in

italics: for example, very likely. This is consistent with AR5. In this Report, unless stated otherwise, square brackets [x to y] are used to provide the assessed very likely range, or

90% interval.

futures. It considers long-term characteristics, impacts, risks and costs

in adaptation and mitigation pathways in the context of sustainable

development. Section 4, ‘Near- Term Responses in a Changing Climate’,

assesses opportunities for scaling up effective action in the period up

to 2040, in the context of climate pledges, and commitments, and the

pursuit of sustainable development.

Based on scientiﬁc understanding, key ﬁndings can be formulated as

statements of fact or associated with an assessed level of conﬁdence

using the IPCC calibrated language

. The scientiﬁc ﬁndings are

drawn from the underlying reports and arise from their Summary for

Policymakers (hereafter SPM), Technical Summary (hereafter TS), and

underlying chapters and are indicated by {} brackets. Figure 1.1 shows

the Synthesis Report Figures Key, a guide to visual icons that are used

across multiple ﬁgures within this report.

1. Introduction

Introduction

Section 1

Figure 1.1: The Synthesis Report ﬁgures key.

Italicized ‘annotations’

Simple explanations written

in non-technical language

Axis labels

Synthesis Report

ﬁgures key

these help non-experts

navigate complex content

GHG emissions

Temperature

Cost or budget

Net zero

°C

net zero

Section 2

Current Status and Trends

Section 2

Section 1

Section 2

2.1 Observed Changes, Impacts and Attribution

Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming,

with global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020. Global greenhouse gas emissions

have continued to increase over 2010–2019, with unequal historical and ongoing contributions arising from

unsustainable energy use, land use and land-use change, lifestyles and patterns of consumption and production

across regions, between and within countries, and between individuals (high conﬁdence). Human-caused climate

change is already affecting many weather and climate extremes in every region across the globe. This has led to

widespread adverse impacts on food and water security, human health and on economies and society and related

losses and damages

to nature and people (high conﬁdence). Vulnerable communities who have historically

contributed the least to current climate change are disproportionately affected (high conﬁdence).

In this report, the term ‘losses and damages’ refers to adverse observed impacts and/or projected risks and can be economic and/or non-economic. (See Annex I: Glossary)

Section 2: Current Status and Trends

2.1.1. Observed Warming and its Causes

Global surface temperature was around 1.1°C above 1850–1900 in

2011–2020 (1.09 [0.95 to 1.20]°C)

, with larger increases

over land (1.59 [1.34 to 1.83]°C) than over the ocean

(0.88 [0.68 to 1.01]°C)

. Observed warming is human-caused, with

warming from greenhouse gases (GHG), dominated by CO

and

methane (CH

), partly masked by aerosol cooling (Figure 2.1).

Global surface temperature in the ﬁrst two decades of the 21st century

(2001–2020) was 0.99 [0.84 to 1.10]°C higher than 1850–1900. Global

surface temperature has increased faster since 1970 than in any other

50-year period over at least the last 2000 years (high conﬁdence). The

likely range of total human-caused global surface temperature increase

from 1850–1900 to 2010–2019

is 0.8°C to 1.3°C, with a best estimate

of 1.07°C. It is likely that well-mixed GHGs

contributed a warming

of 1.0°C to 2.0°C, and other human drivers (principally aerosols)

contributed a cooling of 0.0°C to 0.8°C, natural (solar and volcanic)

drivers changed global surface temperature by ±0.1°C and internal

variability changed it by ±0.2°C. {WGI SPM A.1, WGI SPM A.1.2,

WGI SPM A.1.3, WGI SPM A.2.2, WGI Figure SPM.2; SRCCL TS.2}

Observed increases in well-mixed GHG concentrations since around

1750 are unequivocally caused by GHG emissions from human activities.

Land and ocean sinks have taken up a near-constant proportion

(globally about 56% per year) of CO

emissions from human activities over

In this report, the term ‘losses and damages’ refers to adverse observed impacts and/or projected risks and can be economic and/or non-economic. (See Annex I: Glossary)

The estimated increase in global surface temperature since AR5 is principally due to further warming since 2003–2012 (+0.19 [0.16 to 0.22]°C). Additionally, methodological

advances and new datasets have provided a more complete spatial representation of changes in surface temperature, including in the Arctic. These and other improvements

have also increased the estimate of global surface temperature change by approximately 0.1°C, but this increase does not represent additional physical warming since AR5

{WGI SPM A1.2 and footnote 10}

For 1850–1900 to 2013–2022 the updated calculations are 1.15 [1.00 to 1.25]°C for global surface temperature, 1.65 [1.36 to 1.90]°C for land temperatures and

0.93 [0.73 to 1.04]°C for ocean temperatures above 1850–1900 using the exact same datasets (updated by 2 years) and methods as employed in WGI.

The period distinction with the observed assessment arises because the attribution studies consider this slightly earlier period. The observed warming to 2010–2019 is

1.06 [0.88 to 1.21]°C. {WGI SPM footnote 11}

Contributions from emissions to the 2010–2019 warming relative to 1850–1900 assessed from radiative forcing studies are: CO

0.8 [0.5 to 1.2]°C; methane 0.5 [0.3 to 0.8]°C;

nitrous oxide 0.1 [0.0 to 0.2]°C and ﬂuorinated gases 0.1 [0.0 to 0.2]°C.

For 2021 (the most recent year for which ﬁnal numbers are available) concentrations using the same observational products and methods as in AR6 WGI are: 415 ppm CO

;

1896 ppb CH

; and 335 ppb N

O. Note that the CO

is reported here using the WMO-CO

-X2007 scale to be consistent with WGI. Operational CO

reporting has since been

updated to use the WMO-CO

-X2019 scale.

the past six decades, with regional differences (high conﬁdence). In 2019,

atmospheric CO

concentrations reached 410 parts per million (ppm), CH

reached 1866 parts per billion (ppb) and nitrous oxide (N

O) reached 332 ppb

Other major contributors to warming are tropospheric ozone (O

) and

halogenated gases. Concentrations of CH

and N

O have increased to

levels unprecedented in at least 800,000 years (very high conﬁdence),

and there is high conﬁdence that current CO

concentrations are

higher than at any time over at least the past two million years. Since

1750, increases in CO

(47%) and CH

(156%) concentrations far

exceed – and increases in N

O (23%) are similar to – the natural

multi-millennial changes between glacial and interglacial periods over at

least the past 800,000 years (very high conﬁdence). The net cooling effect

which arises from anthropogenic aerosols peaked in the late 20th century

(high conﬁdence). {WGI SPM A1.1, WGI SPM A1.3, WGI SPM A.2.1,

WGI Figure SPM.2, WGI TS 2.2, WGI 2ES, WGI Figure 6.1}

Current Status and Trends

Section 2

Increased concentrations

of GHGs in the atmosphere

Increased emissions of

greenhouse gases (GHGs)

c) Changes in global surface temperature

Carbon dioxide

Methane

d) Humans are responsible

400

350

300

1000

1500

500

–0.5

–1.0

0.0

0.5

1.0

1.5

2.0

Observed

–0.5

–1.0

0.0

0.5

1.0

1.5

2.0

Total human inﬂuence

Observed warming

Well-mixed GHG

Other human drivers*

Solar and volcanic drivers

Internal variability

Observed warming is driven by emissions

from human activities with GHG warming

partly masked by aerosol cooling 2010–2019

(change from 1850–1900)

1.0

0.2

Global surface temperature has increased by

1.1°C by 2011-2020 compared to 1850-1900

Concentrations of GHGs have increased rapidly since 1850

(scaled to match their assessed contributions to warming over 1850–1900

to 2010–2019)

Greenhouse gas (GHG) emissions resulting

from human activities continue to increase

Human activities are responsible for global warming

1850 1900 1950 2000 2020

1850 1900 1950 2000 2019

Non-CO

emissions

from

fossil fuels

and industry

Parts per million (ppm)

GHG Emissions (GtCO

-eq/yr)

Parts per billion (ppb)

°C

1850 1900 1950 2000 2019

°C

from Land

Use, Land-Use

Change and

Forestry

(LULUCF)

warmest

multi-century

period in more

than 100,000

years

410 ppm CO

1866 ppb CH

332 ppb N

200

400

Parts per billion (ppb)

Nitrous oxide

°C

0 0.5 1 1.5

Key

*Other human drivers are predominantly cooling aerosols, but also

warming aerosols, land-use change (land-use reﬂectance) and ozone.

Figure 2.1: The causal chain from emissions to resulting

warming of the climate system. Emissions of GHG have

increased rapidly over recent decades (panel (a)). Global net

anthropogenic GHG emissions include CO

from fossil fuel

combustion and industrial processes (CO

-FFI) (dark green);

net CO

from land use, land-use change and forestry (CO

-LULUCF)

(green); CH

; N

O; and ﬂuorinated gases (HFCs, PFCs, SF

, NF

)

(light blue). These emissions have led to increases in the atmospheric

concentrations of several GHGs including the three major well-mixed

GHGs CO

, CH

and N

O (panel (b), annual values). To indicate their

relative importance each subpanel’s vertical extent for CO

, CH

and

O is scaled to match the assessed individual direct effect (and,

in the case of CH

indirect effect via atmospheric chemistry impacts

on tropospheric ozone) of historical emissions on temperature

change from 1850–1900 to 2010–2019. This estimate arises from

an assessment of effective radiative forcing and climate sensitivity.

The global surface temperature (shown as annual anomalies from

a 1850–1900 baseline) has increased by around 1.1°C since

1850–1900 (panel (c)). The vertical bar on the right shows the

estimated temperature (very likely range) during the warmest

multi-century period in at least the last 100,000 years, which

occurred around 6500 years ago during the current interglacial

period (Holocene). Prior to that, the next most recent warm period

was about 125,000 years ago, when the assessed multi-century

temperature range [0.5°C to 1.5°C] overlaps the observations of

the most recent decade. These past warm periods were caused

by slow (multi-millennial) orbital variations. Formal detection and

attribution studies synthesise information from climate models

and observations and show that the best estimate is that all the

warming observed between 1850–1900 and 2010–2019 is caused

by humans (panel (d)). The panel shows temperature change

attributed to: total human inﬂuence; its decomposition into changes

in GHG concentrations and other human drivers (aerosols, ozone

and land-use change (land-use reﬂectance)); solar and volcanic

drivers; and internal climate variability. Whiskers show likely ranges.

{WGI SPM A.2.2, WGI Figure SPM.1, WGI Figure SPM.2, WGI TS2.2,

WGI 2.1; WGIII Figure SPM.1, WGIII A.III.II.2.5.1}

Section 2

Section 1

Section 2

Average annual GHG emissions during 2010–2019 were higher

than in any previous decade, but the rate of growth between

2010 and 2019 (1.3% yr

-1

) was lower than that between 2000

and 2009 (2.1% yr

-1

)

. Historical cumulative net CO

emissions from

1850 to 2019 were 2400 ±240 GtCO

. Of these, more than half (58%)

occurred between 1850 and 1989 [1400 ±195 GtCO

], and about 42%

between 1990 and 2019 [1000 ±90 GtCO

]. Global net anthropogenic

GHG emissions have been estimated to be 59±6.6 GtCO

-eq in 2019,

about 12% (6.5 GtCO

-eq) higher than in 2010 and 54% (21 GtCO

-eq)

higher than in 1990. By 2019, the largest growth in gross emissions

occurred in CO

from fossil fuels and industry (CO

-FFI) followed by

, whereas the highest relative growth occurred in fluorinated

gases (F-gases), starting from low levels in 1990. (high confidence)

{WGIII SPM B1.1, WGIII SPM B.1.2, WGIII SPM B.1.3, WGIII Figure SPM.1,

WGIII Figure SPM.2}

Regional contributions to global human-caused GHG emissions

continue to differ widely. Historical contributions of CO

emissions

vary substantially across regions in terms of total magnitude, but also

in terms of contributions to CO

-FFI (1650 ± 73 GtCO

-eq) and net

-LULUCF (760 ± 220 GtCO

-eq) emissions (Figure 2.2). Variations

in regional and national per capita emissions partly reﬂect different

development stages, but they also vary widely at similar income

levels. Average per capita net anthropogenic GHG emissions in 2019

ranged from 2.6 tCO

-eq to 19 tCO

-eq across regions (Figure 2.2).

Least Developed Countries (LDCs) and Small Island Developing States (SIDS)

have much lower per capita emissions (1.7 tCO

-eq and 4.6 tCO

-eq,

respectively) than the global average (6.9 tCO

-eq), excluding

-LULUCF. Around 48% of the global population in 2019 lives in countries

emitting on average more than 6 tCO

-eq per capita, 35% of the global

population live in countries emitting more than 9 tCO

-eq per capita

(excluding CO

-LULUCF) while another 41% live in countries emitting less

than 3 tCO

-eq per capita. A substantial share of the population in these

low-emitting countries lack access to modern energy services. (high conﬁdence)

{WGIII SPM B.3, WGIII SPM B3.1, WGIII SPM B.3.2, WGIII SPM B.3.3}

Net GHG emissions have increased since 2010 across all major

sectors (high conﬁdence). In 2019, approximately 34% (20 GtCO

-eq)

of net global GHG emissions came from the energy sector, 24%

(14 GtCO

-eq) from industry, 22% (13 GtCO

-eq) from AFOLU, 15%

(8.7 GtCO

-eq) from transport and 6% (3.3 GtCO

-eq) from buildings

(high conﬁdence). Average annual GHG emissions growth between

GHG emission metrics are used to express emissions of different GHGs in a common unit. Aggregated GHG emissions in this report are stated in CO

-equivalents (CO

-eq) using

the Global Warming Potential with a time horizon of 100 years (GWP100) with values based on the contribution of Working Group I to the AR6. The AR6 WGI and WGIII reports

contain updated emission metric values, evaluations of different metrics with regard to mitigation objectives, and assess new approaches to aggregating gases. The choice of

metric depends on the purpose of the analysis and all GHG emission metrics have limitations and uncertainties, given that they simplify the complexity of the physical climate

system and its response to past and future GHG emissions. {WGI SPM D.1.8, WGI 7.6; WGIII SPM B.1, WGIII Cross-Chapter Box 2.2} (Annex I: Glossary)

Territorial emissions

GHG emission levels are rounded to two signiﬁcant digits; as a consequence, small differences in sums due to rounding may occur. {WGIII SPM footnote 8}

Comprising a gross sink of -12.5 (±3.2) GtCO

-1

resulting from responses of all land to both anthropogenic environmental change and natural climate variability, and

net anthropogenic CO

-LULUCF emissions +5.9 (±4.1) GtCO

-1

based on book-keeping models. {WGIII SPM Footnote 14}

This estimate is based on consumption-based accounting, including both direct emissions from within urban areas, and indirect emissions from outside urban areas related to

the production of electricity, goods and services consumed in cities. These estimates include all CO

and CH

emission categories except for aviation and marine bunker fuels,

land-use change, forestry and agriculture. {WGIII SPM footnote 15}

2010 and 2019 slowed compared to the previous decade in energy

supply (from 2.3% to 1.0%) and industry (from 3.4% to 1.4%) but

remained roughly constant at about 2% yr

–1

in the transport sector

(high conﬁdence). About half of total net AFOLU emissions are from

LULUCF, predominantly from deforestation (medium conﬁdence).

Land overall constituted a net sink of –6.6 (±4.6) GtCO

–1

for the period

2010–2019

(medium conﬁdence). {WGIII SPM B.2, WGIII SPM B.2.1,

WGIII SPM B.2.2, WGIII TS 5.6.1}

Human-caused climate change is a consequence of more than

a century of net GHG emissions from energy use, land-use and

land use change, lifestyle and patterns of consumption, and

production. Emissions reductions in CO

from fossil fuels and industrial

processes (CO

-FFI), due to improvements in energy intensity of GDP

and carbon intensity of energy, have been less than emissions increases

from rising global activity levels in industry, energy supply, transport,

agriculture and buildings. The 10% of households with the highest per

capita emissions contribute 34–45% of global consumption-based

household GHG emissions, while the middle 40% contribute 40–53%,

and the bottom 50% contribute 13–15%. An increasing share of

emissions can be attributed to urban areas (a rise from about 62%

to 67–72% of the global share between 2015 and 2020). The drivers

of urban GHG emissions

are complex and include population size,

income, state of urbanisation and urban form. (high conﬁdence)

{WGIII SPM B.2, WGIII SPM B.2.3, WGIII SPM B.3.4, WGIII SPM D.1.1}

Current Status and Trends

Section 2

Key

Population (millions)

0 2000 4000 6000 8000

Middle East

Africa

Eastern Asia

South-East Asia and Paciﬁc

Latin America and Caribbean

Europe

Southern Asia

North America

Australia, Japan and New Zealand

Eastern Europe and West-Central Asia

Africa

Australia, Japan and New Zealand

Eastern Asia

Eastern Europe and West-Central Asia

Europe

International

shipping and aviation

Latin America and Caribbean

Middle East

North America

South-East Asia and Paciﬁc

Southern Asia

200

400

600

16%

12%

11%

10%

23%

GHG

201919901850

Timeframes represented in these graphs

d) Regional indicators (2019) and regional production vs consumption accounting (2018)

Production-based emissions (tCO

FFI per person, based on 2018 data)

1.2 10 8.4 9.2 6.5 2.8 8.7 16 2.6 1.6

Consumption-based emissions (tCO

FFI per person, based on 2018 data)

0.84 11 6.7 6.2 7.8 2.8 7.6 17 2.5 1.5

Population (million persons, 2019) 1292 157 1471 291 620 646 252 366 674 1836

GHG per capita (tCO

-eq per person)

3.9 13 11 13 7.8 9.2 13 19 7.9 2.6

GDP per capita (USD1000

PPP

2017 per person)

5.0 43 17 20 43 15 20 61 12 6.2

Net GHG 2019

(production basis)

FFI, 2018, per person

GHG emissions intensity (tCO

-eq / USD1000

PPP

2017) 0.78 0.30 0.62 0.64 0.18 0.61 0.64 0.31 0.65 0.42

Africa Australia,

Japan,

New

Zealand

Eastern

Asia

Eastern

Europe,

West-

Central Asia

Europe Latin

America

and

Caribbean

Middle

East

North

America

South-East

Asia and

Pacic

Southern

Asia

GDP per capita in 2019 in USD2017 currency purchasing power basis.

Includes CO

FFI, CO

LULUCF and Other GHGs, excluding international aviation and shipping.

The regional groupings used in this ﬁgure are for statistical

purposes only and are described in WGIII Annex II, Part I.

c) Global net anthropogenic GHG emissions by region (1990–2019)

20001990 2010 2019

Eastern Asia

North America

Latin America and Caribbean

South-East Asia and Paciﬁc

Africa

Southern Asia

Europe

Eastern Europe and West-Central Asia

Middle East

Australia, Japan and New Zealand

International shipping and aviation

13%

18%

10%

16%

14%

16%

19%

11%

13%

27%

24%

12%

14%

10%

11%

10%

Total:

38 GtCO

-eq

42 GtCO

-eq

53 GtCO

-eq

59 GtCO

-eq

Emissions have grown in most regions but are distributed unevenly,

both in the present day and cumulatively since 1850

b) Net anthropogenic GHG emissions per capita

and for total population, per region (2019)

a) Historical cumulative net anthropogenic

emissions per region (1850–2019)

GHG emissions (tCO

-eq per capita)

emissions (GtCO

)

Net CO

from land use, land use change, forestry (CO

LULUCF)

Other GHG emissions

Fossil fuel and industry (CO

FFI)

All GHG emissions

GHG emissions per year (GtCO

-eq/yr)

Section 2

Section 1

Section 2

Figure 2.2: Regional GHG emissions, and the regional proportion of total cumulative production-based CO

emissions from 1850 to 2019. Panel (a) shows the

share of historical cumulative net anthropogenic CO

emissions per region from 1850 to 2019 in GtCO

. This includes CO

-FFI and CO

-LULUCF. Other GHG emissions are not included.

-LULUCF emissions are subject to high uncertainties, reﬂected by a global uncertainty estimate of ±70% (90% conﬁdence interval). Panel (b) shows the distribution of regional

GHG emissions in tonnes CO

-eq per capita by region in 2019. GHG emissions are categorised into: CO

-FFI; net CO

-LULUCF; and other GHG emissions (CH

, N

O, ﬂuorinated gases,

expressed in CO

-eq using GWP100-AR6). The height of each rectangle shows per capita emissions, the width shows the population of the region, so that the area of the rectangles

refers to the total emissions for each region. Emissions from international aviation and shipping are not included. In the case of two regions, the area for CO

-LULUCF is below the

axis, indicating net CO

removals rather than emissions. Panel (c) shows global net anthropogenic GHG emissions by region (in GtCO

-eq yr

–1

(GWP100-AR6)) for the time period

1990–2019. Percentage values refer to the contribution of each region to total GHG emissions in each respective time period. The single-year peak of emissions in 1997 was due to

higher CO

-LULUCF emissions from a forest and peat ﬁre event in South East Asia. Regions are as grouped in Annex II of WGIII. Panel (d) shows population, gross domestic product

(GDP) per person, emission indicators by region in 2019 for total GHG per person, and total GHG emissions intensity, together with production-based and consumption-based CO

-FFI data,

which is assessed in this report up to 2018. Consumption-based emissions are emissions released to the atmosphere in order to generate the goods and services consumed by a

certain entity (e.g., region). Emissions from international aviation and shipping are not included. {WGIII Figure SPM.2}

2.1.2. Observed Climate System Changes and Impacts to

Date

It is unequivocal that human inﬂuence has warmed the

atmosphere, ocean and land. Widespread and rapid changes in

the atmosphere, ocean, cryosphere and biosphere have occurred

(Table 2.1). The scale of recent changes across the climate system as

a whole and the present state of many aspects of the climate system

are unprecedented over many centuries to many thousands of years. It

is very likely that GHG emissions were the main driver

of tropospheric

warming and extremely likely that human-caused stratospheric ozone

depletion was the main driver of stratospheric cooling between 1979

and the mid-1990s. It is virtually certain that the global upper ocean

(0-700m) has warmed since the 1970s and extremely likely that

human inﬂuence is the main driver. Ocean warming accounted for

91% of the heating in the climate system, with land warming, ice loss

and atmospheric warming accounting for about 5%, 3% and 1%,

respectively (high conﬁdence). Global mean sea level increased by 0.20

[0.15 to 0.25] m between 1901 and 2018. The average rate of sea level

rise was 1.3 [0.6 to 2.1]mm yr

-1

between 1901 and 1971, increasing to

1.9 [0.8 to 2.9] mm yr

-1

between 1971 and 2006, and further increasing

to 3.7 [3.2 to –4.2] mm yr

-1

between 2006 and 2018 (high conﬁdence).

Human inﬂuence was very likely the main driver of these increases

since at least 1971 (Figure 3.4). Human inﬂuence is very likely the main

driver of the global retreat of glaciers since the 1990s and the decrease

in Arctic sea ice area between 1979–1988 and 2010–2019. Human

inﬂuence has also very likely contributed to decreased Northern Hemisphere

spring snow cover and surface melting of the Greenland ice sheet. It is

virtually certain that human-caused CO

emissions are the main driver

of current global acidiﬁcation of the surface open ocean. {WGI SPM A.1,

WGI SPM A.1.3, WGI SPM A.1.5, WGI SPM A.1.6, WG1 SPM A1.7,

WGI SPM A.2, WG1.SPM A.4.2; SROCC SPM.A.1, SROCC SPM A.2}

Human-caused climate change is already affecting many weather and

climate extremes in every region across the globe. Evidence of observed

changes in extremes such as heatwaves, heavy precipitation, droughts,

and tropical cyclones, and, in particular, their attribution to human

inﬂuence, has strengthened since AR5 (Figure 2.3). It is virtually certain

that hot extremes (including heatwaves) have become more frequent and

more intense across most land regions since the 1950s (Figure 2.3), while cold

extremes (including cold waves) have become less frequent and less severe,

with high conﬁdence that human-caused climate change is the main

driver of these changes. Marine heatwaves have approximately doubled

‘Main driver’ means responsible for more than 50% of the change. {WGI SPM footnote 12}

See Annex I: Glossary.

in frequency since the 1980s (high conﬁdence), and human inﬂuence

has very likely contributed to most of them since at least 2006. The

frequency and intensity of heavy precipitation events have increased

since the 1950s over most land areas for which observational data

are sufﬁcient for trend analysis (high conﬁdence), and human-caused

climate change is likely the main driver (Figure 2.3). Human-caused

climate change has contributed to increases in agricultural and ecological

droughts in some regions due to increased land evapotranspiration

(medium conﬁdence) (Figure 2.3). It is likely that the global proportion

of major (Category 3–5) tropical cyclone occurrence has increased over

the last four decades. {WGI SPM A.3, WGI SPM A3.1, WGI SPM A3.2;

WGI SPM A3.4; SRCCL SPM.A.2.2; SROCC SPM. A.2}

Climate change has caused substantial damages, and increasingly

irreversible

losses, in terrestrial, freshwater, cryospheric and

coastal and open ocean ecosystems (high conﬁdence). The extent

and magnitude of climate change impacts are larger than estimated

in previous assessments (high conﬁdence). Approximately half of the

species assessed globally have shifted polewards or, on land, also to

higher elevations (very high conﬁdence). Biological responses including

changes in geographic placement and shifting seasonal timing are often

not sufﬁcient to cope with recent climate change (very high conﬁdence).

Hundreds of local losses of species have been driven by increases in

the magnitude of heat extremes (high conﬁdence) and mass mortality

events on land and in the ocean (very high conﬁdence). Impacts on

some ecosystems are approaching irreversibility such as the impacts

of hydrological changes resulting from the retreat of glaciers, or the

changes in some mountain (medium conﬁdence) and Arctic ecosystems

driven by permafrost thaw (high conﬁdence). Impacts in ecosystems

from slow-onset processes such as ocean acidiﬁcation, sea level rise

or regional decreases in precipitation have also been attributed to

human-caused climate change (high conﬁdence). Climate change

has contributed to desertiﬁcation and exacerbated land degradation,

particularly in low lying coastal areas, river deltas, drylands and in

permafrost areas (high conﬁdence). Nearly 50% of coastal wetlands

have been lost over the last 100 years, as a result of the combined

effects of localised human pressures, sea level rise, warming

and extreme climate events (high confidence). {WGII SPM B.1.1,

WGII SPM B.1.2, WGII Figure SPM.2.A, WGII TS.B.1; SRCCL SPM A.1.5,

SRCCL SPM A.2, SRCCL SPM A.2.6, SRCCL Figure SPM.1; SROCC SPM A.6.1,

SROCC SPM, A.6.4, SROCC SPM A.7}

Current Status and Trends

Section 2

Table 2.1: Assessment of observed changes in large-scale indicators of mean climate across climate system components, and their attribution to human

inﬂuence. The colour coding indicates the assessed conﬁdence in / likelihood

of the observed change and the human contribution as a driver or main driver (speciﬁed in that case)

where available (see colour key). Otherwise, explanatory text is provided. {WGI Table TS.1}

Based on scientiﬁc understanding, key ﬁndings can be formulated as statements of fact or associated with an assessed level of conﬁdence indicated using the IPCC calibrated language.

likely range of human contribution

([0.8-1.3°C]) encompasses the very likely

range of observed warming ([0.9-1.2°C])

Observed change

assessment

Human contribution

assessment

Main driver

Main driver 1979 - mid-1990s

Southern Hemisphere

Main driver

Limited evidence & medium agreement

Main driver

Change in indicator

Warming of global mean surface air temperature since 1850-1900

Warming of the troposphere since 1979

Cooling of the lower stratosphere since the mid-20th century

Large-scale precipitation and upper troposphere humidity changes since 1979

Expansion of the zonal mean Hadley Circulation since the 1980s

Ocean heat content increase since the 1970s

Salinity changes since the mid-20th century

Global mean sea level rise since 1970

Arctic sea ice loss since 1979

Reduction in Northern Hemisphere springtime snow cover since 1950

Greenland ice sheet mass loss since 1990s

Antarctic ice sheet mass loss since 1990s

Retreat of glaciers

Increased amplitude of the seasonal cycle of

atmospheric CO

since the early 1960s

Acidiﬁcation of the global surface ocean

Mean surface air temperature over land

(about 40% larger than global mean warming)

Warming of the global climate system since preindustrial times

medium

conﬁdence

likely / high

conﬁdence

very likely extremely

likely

virtually

certain

fact

Atmosphere

and water cycle

Ocean

Cryosphere

Carbon cycle

Land climate

Synthesis

Key

Section 2

Section 1

Section 2

Climate change has impacted human and natural systems across the

world with those who have generally least contributed to climate

change being most vulnerable

a) Synthesis of assessment of observed change in hot extremes, heavy precipitation and

drought, and conﬁdence in human contribution to the observed changes in the world’s regions

Increase

Decrease

Limited data and/or literature

Low agreement in the type of change

Key

Type of observed change since the 1950s

High

Medium

Low due to limited agreement

Low due to limited evidence

Conﬁdence in human contribution

to the observed change

NWN

Each hexagon corresponds

to a region

North-Western

North America

IPCC AR6 WGI reference regions:

North America: NWN (North-Western North

America, NEN (North-Eastern North

America), WNA (Western North America),

CNA (Central North America), ENA (Eastern

North America), Central America: NCA

(Northern Central America), SCA (Southern

Central America), CAR (Caribbean), South

America: NWS (North-Western South

America), NSA (Northern South America),

NES (North-Eastern South America), SAM

(South American Monsoon), SWS

(South-Western South America), SES

(South-Eastern South America), SSA

(Southern South America), Europe: GIC

(Greenland/Iceland), NEU (Northern Europe),

WCE (Western and Central Europe), EEU

(Eastern Europe), MED (Mediterranean),

Africa: MED (Mediterranean), SAH (Sahara),

WAF (Western Africa), CAF (Central Africa),

NEAF (North Eastern Africa), SEAF (South

Eastern Africa), WSAF (West Southern

Africa), ESAF (East Southern Africa), MDG

(Madagascar), Asia: RAR (Russian Arctic),

WSB (West Siberia), ESB (East Siberia), RFE

(Russian Far East), WCA (West Central Asia),

ECA (East Central Asia), TIB (Tibetan

Plateau), EAS (East Asia), ARP (Arabian

Peninsula), SAS (South Asia), SEA (South East

Asia), Australasia: NAU (Northern Australia),

CAU (Central Australia), EAU (Eastern

Australia), SAU (Southern Australia), NZ

(New Zealand), Small Islands: CAR

(Caribbean), PAC (Paciﬁc Small Islands)

NWN NEN

GIC

NEU RAR

WNA CNA ENA WCE EEU WSB ESB RFE

NCA MED WCA ECA TIB EAS

SCA CAR SAH ARP SAS SEA

NWS NSA WAF CAF NEAF

NAU

SAM NES WSAF SEAF

CAU EAU

SWS SES ESAF

SSA

MDG

PAC

Africa

Asia

Australasia

North

America

Central

America

South

America

Europe

Small

Islands

Small

Islands

NWN NEN

GIC

NEU RAR

WNA CNA ENA WCE EEU WSB ESB RFE

NCA MED WCA ECA TIB EAS

SCA CAR SAH ARP SAS SEA

NWS NSA WAF CAF NEAF

NAU

SAM NES WSAF SEAF

CAU EAU

SWS SES ESAF

SSA

MDG

PAC

Africa

Asia

Australasia

North

America

Central

America

South

America

Europe

Small

Islands

Small

Islands

NWN NEN

GIC

NEU RAR

WNA CNA ENA WCE EEU WSB ESB RFE

NCA MED WCA ECA TIB EAS

SCA CAR SAH ARP SAS SEA

NWS NSA WAF CAF NEAF

NAU

SAM NES WSAF SEAF

CAU EAU

SWS SES ESAF

SSA

MDG

PAC

Africa

Asia

Australasia

North

America

Central

America

South

America

Europe

Small

Islands

Small

Islands

Hot extremes

Heavy precipitation

Agricultural and ecological drought

including heatwaves

Hazard

Dimension of Risk:

Current Status and Trends

Section 2

Terrestrial

Freshwater

Ocean

Changes in

ecosystem structure

Terrestrial

Freshwater

Ocean

Species range shifts

Terrestrial

Freshwater

Ocean

Changes in seasonal

timing (phenology)

Water availability

and food production

Health and wellbeing

Cities, settlements

and infrastructure

Asia

Africa

Global

Australasia

Europe

Central &

South America

North

America

Small Islands

Physical water availability

Agriculture/crop production

Fisheries yields and aquaculture production

Animal and livestock

health and productivity

Infectious diseases

Displacement

Mental health

Heat, malnutrition and harm from wildﬁre

Inland ﬂooding and

associated damages

Flood/storm induced

damages in coastal areas

Damages to key economic sectors

Damages to infrastructure

c) Observed impacts and related losses

and damages of climate change

2019 emissions per capita of 180 nations in tons of CO

b) Vulnerability of population & per capita emissions per country in 2019

more vulnerable

countries generally

have lower emissions

per capita

Increased climate impacts

HUMAN SYSTEMS

ECOSYSTEMS

Adverse impacts

Adverse and positive impacts

Climate-driven changes observed,

no assessment of impact direction

100

100 3020 40 70 80

high

low

ECOSYSTEMS HUMAN SYSTEMS

Key

Conﬁdence in attribution

to climate change

High or very high

Medium

Low

Evidence limited, insufﬁcient

Not assessed

Vulnerability

Dimension

of Risk:

Impact

Dimension

of Risk:

Vulnerability assessed on national data.

Vulnerability differs between and within countries

and is exacerbated by inequity and marginalisation.

Relative average national

vulnerability per capita by global

indices INFORM and WRI (2019)

Section 2

Section 1

Section 2

Climate change has reduced food security and affected water

security due to warming, changing precipitation patterns,

reduction and loss of cryospheric elements, and greater frequency

and intensity of climatic extremes, thereby hindering efforts to

meet Sustainable Development Goals (high conﬁdence). Although

overall agricultural productivity has increased, climate change has slowed

this growth in agricultural productivity over the past 50 years globally

(medium conﬁdence), with related negative crop yield impacts mainly

recorded in mid- and low latitude regions, and some positive impacts

in some high latitude regions (high conﬁdence). Ocean warming in

the 20th century and beyond has contributed to an overall decrease

in maximum catch potential (medium conﬁdence), compounding the

impacts from overﬁshing for some ﬁsh stocks (high conﬁdence). Ocean

warming and ocean acidiﬁcation have adversely affected food production

from shellﬁsh aquaculture and ﬁsheries in some oceanic regions (high

conﬁdence). Current levels of global warming are associated with

moderate risks from increased dryland water scarcity (high conﬁdence).

Roughly half of the world’s population currently experiences severe water

scarcity for at least some part of the year due to a combination of climatic

and non-climatic drivers (medium conﬁdence) (Figure 2.3). Unsustainable

agricultural expansion, driven in part by unbalanced diets

, increases

ecosystem and human vulnerability and leads to competition for land

and/or water resources (high conﬁdence). Increasing weather and climate

extreme events have exposed millions of people to acute food insecurity

and reduced water security, with the largest impacts observed in many

locations and/or communities in Africa, Asia, Central and South America,

LDCs, Small Islands and the Arctic, and for small-scale food producers,

low-income households and Indigenous Peoples globally (high conﬁdence).

{WGII SPM B.1.3, WGII SPM.B.2.3, WGII Figure SPM.2, WGII TS B.2.3,

WGII TS Figure TS. 6; SRCCL SPM A.2.8, SRCCL SPM A.5.3; SROCC SPM A.5.4.,

SROCC SPM A.7.1, SROCC SPM A.8.1, SROCC Figure SPM.2}

Balanced diets feature plant-based foods, such as those based on coarse grains, legumes fruits and vegetables, nuts and seeds, and animal-source foods produced in resilient,

sustainable and low-GHG emissions systems, as described in SRCCL. {WGII SPM Footnote 32}

Acute food insecurity can occur at any time with a severity that threatens lives, livelihoods or both, regardless of the causes, context or duration, as a result of shocks risking

determinants of food security and nutrition, and is used to assess the need for humanitarian action. {WGII SPM, footnote 30}

Slow-onset events are described among the climatic-impact drivers of the AR6 WGI and refer to the risks and impacts associated with e.g., increasing temperature means,

desertiﬁcation, decreasing precipitation, loss of biodiversity, land and forest degradation, glacial retreat and related impacts, ocean acidiﬁcation, sea level rise and salinization.

{WGII SPM footnote 29}

In urban settings, climate change has caused adverse impacts on

human health, livelihoods and key infrastructure (high conﬁdence).

Hot extremes including heatwaves have intensiﬁed in cities (high

conﬁdence), where they have also worsened air pollution events

(medium conﬁdence) and limited functioning of key infrastructure

(high conﬁdence). Urban infrastructure, including transportation, water,

sanitation and energy systems have been compromised by extreme

and slow-onset events

, with resulting economic losses, disruptions of

services and impacts to well-being (high conﬁdence). Observed impacts

are concentrated amongst economically and socially marginalised urban

residents, e.g., those living in informal settlements (high conﬁdence).

Cities intensify human-caused warming locally (very high conﬁdence),

while urbanisation also increases mean and heavy precipitation over and/or

downwind of cities (medium conﬁdence) and resulting runoff intensity

(high conﬁdence). {WGI SPM C.2.6; WGII SPM B.1.5, WGII Figure TS.9,

WGII 6 ES}

Climate change has adversely affected human physical health globally

and mental health in assessed regions (very high conﬁdence), and is

contributing to humanitarian crises where climate hazards interact

with high vulnerability (high conﬁdence). In all regions increases in

extreme heat events have resulted in human mortality and morbidity

(very high conﬁdence). The occurrence of climate-related food-borne and

water-borne diseases has increased (very high conﬁdence). The incidence

of vector-borne diseases has increased from range expansion and/or

increased reproduction of disease vectors (high conﬁdence). Animal and

human diseases, including zoonoses, are emerging in new areas (high

conﬁdence). In assessed regions, some mental health challenges are

associated with increasing temperatures (high conﬁdence), trauma from

extreme events (very high conﬁdence), and loss of livelihoods and culture

Figure 2.3: Both vulnerability to current climate extremes and historical contribution to climate change are highly heterogeneous with many of those who have

least contributed to climate change to date being most vulnerable to its impacts. Panel (a) The IPCC AR6 WGI inhabited regions are displayed as hexagons with identical size

in their approximate geographical location (see legend for regional acronyms). All assessments are made for each region as a whole and for the 1950s to the present. Assessments made

on different time scales or more local spatial scales might differ from what is shown in the ﬁgure. The colours in each panel represent the four outcomes of the assessment on observed

changes. Striped hexagons (white and light-grey) are used where there is low agreement in the type of change for the region as a whole, and grey hexagons are used when there is limited

data and/or literature that prevents an assessment of the region as a whole. Other colours indicate at least medium conﬁdence in the observed change. The conﬁdence level for the human

inﬂuence on these observed changes is based on assessing trend detection and attribution and event attribution literature, and it is indicated by the number of dots: three dots for

high conﬁdence, two dots for medium conﬁdence and one dot for low conﬁdence (single, ﬁlled dot: limited agreement; single, empty dot: limited evidence). For hot extremes, the evidence

is mostly drawn from changes in metrics based on daily maximum temperatures; regional studies using other indices (heatwave duration, frequency and intensity) are used in addition. For

heavy precipitation, the evidence is mostly drawn from changes in indices based on one-day or ﬁve-day precipitation amounts using global and regional studies. Agricultural and

ecological droughts are assessed based on observed and simulated changes in total column soil moisture, complemented by evidence on changes in surface soil moisture, water

balance (precipitation minus evapotranspiration) and indices driven by precipitation and atmospheric evaporative demand. Panel (b) shows the average level of vulnerability amongst a

country’s population against 2019 CO

-FFI emissions per- capita per country for the 180 countries for which both sets of metrics are available. Vulnerability information is based on two

global indicator systems, namely INFORM and World Risk Index. Countries with a relatively low average vulnerability often have groups with high vulnerability within their population and

vice versa. The underlying data includes, for example, information on poverty, inequality, health care infrastructure or insurance coverage. Panel (c) Observed impacts on ecosystems

and human systems attributed to climate change at global and regional scales. Global assessments focus on large studies, multi-species, meta-analyses and large reviews. Regional

assessments consider evidence on impacts across an entire region and do not focus on any country in particular. For human systems, the direction of impacts is assessed and both

adverse and positive impacts have been observed e.g., adverse impacts in one area or food item may occur with positive impacts in another area or food item (for more details and

methodology see WGII SMTS.1). Physical water availability includes balance of water available from various sources including ground water, water quality and demand for water.

Global mental health and displacement assessments reﬂect only assessed regions. Conﬁdence levels reﬂect the assessment of attribution of the observed impact to climate change.

{WGI Figure SPM.3, Table TS.5, Interactive Atlas; WGII Figure SPM.2, WGII SMTS.1, WGII 8.3.1, Figure 8.5; ; WGIII 2.2.3}

Current Status and Trends

Section 2

(high conﬁdence) (Figure 2.3). Climate change impacts on health are

mediated through natural and human systems, including economic

and social conditions and disruptions (high conﬁdence). Climate and

weather extremes are increasingly driving displacement in Africa,

Asia, North America (high conﬁdence), and Central and South America

(medium conﬁdence) (Figure 2.3), with small island states in the

Caribbean and South Paciﬁc being disproportionately affected relative

to their small population size (high conﬁdence). Through displacement

and involuntary migration from extreme weather and climate

events, climate change has generated and perpetuated vulnerability

(medium conﬁdence). {WGII SPM B.1.4, WGII SPM B.1.7}

Human inﬂuence has likely increased the chance of compound

extreme events

since the 1950s. Concurrent and repeated climate

hazards have occurred in all regions, increasing impacts and

risks to health, ecosystems, infrastructure, livelihoods and food

(high conﬁdence). Compound extreme events include increases in the

frequency of concurrent heatwaves and droughts (high conﬁdence); ﬁre

weather in some regions (medium conﬁdence); and compound ﬂooding in

some locations (medium conﬁdence). Multiple risks interact, generating

new sources of vulnerability to climate hazards, and compounding

overall risk (high conﬁdence). Compound climate hazards can overwhelm

adaptive capacity and substantially increase damage (high conﬁdence)).

{WGI SPM A.3.5; WGII SPM. B.5.1, WGII TS.C.11.3}

Economic impacts attributable to climate change are increasingly

affecting peoples’ livelihoods and are causing economic and

societal impacts across national boundaries (high conﬁdence).

Economic damages from climate change have been detected in

climate-exposed sectors, with regional effects to agriculture, forestry,

ﬁshery, energy, and tourism, and through outdoor labour productivity

(high conﬁdence) with some exceptions of positive impacts in regions

with low energy demand and comparative advantages in agricultural

markets and tourism (high conﬁdence). Individual livelihoods have been

affected through changes in agricultural productivity, impacts on human

health and food security, destruction of homes and infrastructure, and loss

of property and income, with adverse effects on gender and social equity

(high conﬁdence). Tropical cyclones have reduced economic growth in

the short-term (high conﬁdence). Event attribution studies and physical

understanding indicate that human-caused climate change increases

heavy precipitation associated with tropical cyclones (high conﬁdence).

Wildﬁres in many regions have affected built assets, economic activity,

and health (medium to high conﬁdence). In cities and settlements, climate

impacts to key infrastructure are leading to losses and damages across water

and food systems, and affect economic activity, with impacts extending

beyond the area directly impacted by the climate hazard (high conﬁdence).

{WGI SPM A.3.4; WGII SPM B.1.6, WGII SPM B.5.2, WGII SPM B.5.3}

Climate change has caused widespread adverse impacts

and related losses and damages to nature and people (high

conﬁdence). Losses and damages are unequally distributed across

systems, regions and sectors (high conﬁdence). Cultural losses, related

See Annex 1: Glossary.

Governance: The structures, processes and actions through which private and public actors interact to address societal goals. This includes formal and informal institutions and

the associated norms, rules, laws and procedures for deciding, managing, implementing and monitoring policies and measures at any geographic or political scale, from global

to local. {WGII SPM Footnote 31}

to tangible and intangible heritage, threaten adaptive capacity and may

result in irrevocable losses of sense of belonging, valued cultural practices,

identity and home, particularly for Indigenous Peoples and those more

directly reliant on the environment for subsistence (medium conﬁdence).

For example, changes in snow cover, lake and river ice, and permafrost

in many Arctic regions, are harming the livelihoods and cultural identity

of Arctic residents including Indigenous populations (high conﬁdence).

Infrastructure, including transportation, water, sanitation and energy

systems have been compromised by extreme and slow-onset events,

with resulting economic losses, disruptions of services and impacts

to well-being (high conﬁdence). {WGII SPM B.1, WGII SPM B.1.2,

WGII SPM.B.1.5, WGII SPM C.3.5, WGII TS.B.1.6; SROCC SPM A.7.1}

Across sectors and regions, the most vulnerable people and

systems have been disproportionately affected by the impacts

of climate change (high conﬁdence). LDCs and SIDS who have much

lower per capita emissions (1.7 tCO

-eq, 4.6 tCO

-eq, respectively) than

the global average (6.9 tCO

-eq) excluding CO

-LULUCF, also have high

vulnerability to climatic hazards, with global hotspots of high human

vulnerability observed in West-, Central- and East Africa, South Asia,

Central and South America, SIDS and the Arctic (high conﬁdence).

Regions and people with considerable development constraints have

high vulnerability to climatic hazards (high conﬁdence). Vulnerability is

higher in locations with poverty, governance challenges and limited

access to basic services and resources, violent conﬂict and high levels

of climate-sensitive livelihoods (e.g., smallholder farmers, pastoralists,

ﬁshing communities) (high conﬁdence). Vulnerability at different spatial

levels is exacerbated by inequity and marginalisation linked to gender,

ethnicity, low income or combinations thereof (high conﬁdence), especially

for many Indigenous Peoples and local communities (high conﬁdence).

Approximately 3.3 to 3.6 billion people live in contexts that are highly

vulnerable to climate change (high conﬁdence). Between 2010 and

2020, human mortality from ﬂoods, droughts and storms was 15 times

higher in highly vulnerable regions, compared to regions with very low

vulnerability (high conﬁdence). In the Arctic and in some high mountain

regions, negative impacts of cryosphere change have been especially felt

among Indigenous Peoples (high conﬁdence). Human and ecosystem

vulnerability are interdependent (high conﬁdence). Vulnerability of

ecosystems and people to climate change differs substantially among and

within regions (very high conﬁdence), driven by patterns of intersecting

socio-economic development, unsustainable ocean and land use,

inequity, marginalisation, historical and ongoing patterns of inequity

such as colonialism, and governance

(high conﬁdence). {WGII SPM B.1,

WGII SPM B.2, WGII SPM B.2.4; WGIII SPM B.3.1; SROCC SPM A.7.1,

SROCC SPM A.7.2}

Section 2

Section 1

Section 2

International climate agreements, rising national ambitions for climate action, along with rising public awareness

are accelerating efforts to address climate change at multiple levels of governance. Mitigation policies have

contributed to a decrease in global energy and carbon intensity, with several countries achieving GHG emission

reductions for over a decade. Low-emission technologies are becoming more affordable, with many low or

zero emissions options now available for energy, buildings, transport, and industry. Adaptation planning and

implementation progress has generated multiple beneﬁts, with effective adaptation options having the potential

to reduce climate risks and contribute to sustainable development. Global tracked ﬁnance for mitigation and

adaptation has seen an upward trend since AR5, but falls short of needs. (high conﬁdence)

2.2.1. Global Policy Setting

The United Nations Framework Convention on Climate Change (UNFCCC),

Kyoto Protocol, and Paris Agreement are supporting rising levels of

national ambition and encouraging the development and implementation

of climate policies at multiple levels of governance (high conﬁdence).

The Kyoto Protocol led to reduced emissions in some countries and

was instrumental in building national and international capacity

for GHG reporting, accounting and emissions markets (high

confidence). The Paris Agreement, adopted under the UNFCCC, with

near universal participation, has led to policy development and

target-setting at national and sub-national levels, particularly in

relation to mitigation but also for adaptation, as well as enhanced

transparency of climate action and support (medium confidence).

Nationally Determined Contributions (NDCs), required under

the Paris Agreement, have required countries to articulate their

priorities and ambition with respect to climate action. {WGII 17.4,

WGII TS D.1.1; WGIII SPM B.5.1, WGIII SPM E.6}

Loss & Damage

was formally recognized in 2013 through establishment

of the Warsaw International Mechanism on Loss and Damage (WIM),

and in 2015, Article 8 of the Paris Agreement provided a legal basis

for the WIM. There is improved understanding of both economic and

non-economic losses and damages, which is informing international

climate policy and which has highlighted that losses and damages are

not comprehensively addressed by current ﬁnancial, governance and

institutional arrangements, particularly in vulnerable developing countries

(high conﬁdence). {WGII SPM C.3.5, WGII Cross-Chapter Box LOSS}

Other recent global agreements that inﬂuence responses to climate

change include the Sendai Framework for Disaster Risk Reduction

(2015-2030), the ﬁnance-oriented Addis Ababa Action Agenda (2015)

and the New Urban Agenda (2016), and the Kigali Amendment to

the Montreal Protocol on Substances that Deplete the Ozone Layer

(2016), among others. In addition, the 2030 Agenda for Sustainable

Development, adopted in 2015 by UN member states, sets out 17

Sustainable Development Goals (SDGs) and seeks to align efforts

globally to prioritise ending extreme poverty, protect the planet and

promote more peaceful, prosperous and inclusive societies. If achieved,

these agreements would reduce climate change, and the impacts on

health, well-being, migration, and conﬂict, among others (very high

conﬁdence). {WGII TS.A.1, WGII 7 ES}

Since AR5, rising public awareness and an increasing diversity

of actors, have overall helped accelerate political commitment

and global efforts to address climate change (medium

See Annex I: Glossary.

conﬁdence). Mass social movements have emerged as catalysing

agents in some regions, often building on prior movements including

Indigenous Peoples-led movements, youth movements, human

rights movements, gender activism, and climate litigation, which is

raising awareness and, in some cases, has inﬂuenced the outcome

and ambition of climate governance (medium conﬁdence). Engaging

Indigenous Peoples and local communities using just-transition and

rights-based decision-making approaches, implemented through

collective and participatory decision-making processes has enabled

deeper ambition and accelerated action in different ways, and at all

scales, depending on national circumstances (medium conﬁdence).

The media helps shape the public discourse about climate change. This

can usefully build public support to accelerate climate action (medium

evidence, high agreement). In some instances, public discourses of

media and organised counter movements have impeded climate

action, exacerbating helplessness and disinformation and fuelling

polarisation, with negative implications for climate action (medium

conﬁdence). {WGII SPM C.5.1, WGII SPM D.2, WGII TS.D.9, WGII TS.D.9.7,

WGII TS.E.2.1, WGII 18.4; WGIII SPM D.3.3, WGIII SPM E.3.3, WGIII TS.6.1,

WGIII 6.7, WGIII 13 ES, WGIII Box.13.7}

2.2.2. Mitigation Actions to Date

There has been a consistent expansion of policies and laws

addressing mitigation since AR5 (high conﬁdence). Climate

governance supports mitigation by providing frameworks through

which diverse actors interact, and a basis for policy development and

implementation (medium conﬁdence). Many regulatory and economic

instruments have already been deployed successfully (high conﬁdence).

By 2020, laws primarily focussed on reducing GHG emissions existed in

56 countries covering 53% of global emissions (medium conﬁdence).

The application of diverse policy instruments for mitigation at the

national and sub-national levels has grown consistently across a

range of sectors (high conﬁdence). Policy coverage is uneven across

sectors and remains limited for emissions from agriculture, and from

industrial materials and feedstocks (high conﬁdence). {WGIII SPM B.5,

WGIII SPM B.5.2, WGIII SPM E.3, WGIII SPM E.4}

Practical experience has informed economic instrument design

and helped to improve predictability, environmental effectiveness,

economic efﬁciency, alignment with distributional goals, and social

acceptance (high conﬁdence). Low-emission technological innovation

is strengthened through the combination of technology-push policies,

together with policies that create incentives for behaviour change and

market opportunities (high conﬁdence) (Section 4.8.3). Comprehensive

and consistent policy packages have been found to be more effective

2.2 Responses Undertaken to Date

Current Status and Trends

Section 2

than single policies (high conﬁdence). Combining mitigation with

policies to shift development pathways, policies that induce lifestyle or

behaviour changes, for example, measures promoting walkable urban

areas combined with electriﬁcation and renewable energy can create

health co-beneﬁts from cleaner air and enhanced active mobility (high

conﬁdence). Climate governance enables mitigation by providing an

overall direction, setting targets, mainstreaming climate action across

policy domains and levels, based on national circumstances and in the

context of international cooperation. Effective governance enhances

regulatory certainty, creating specialised organisations and creating the

context to mobilise ﬁnance (medium conﬁdence). These functions can

be promoted by climate-relevant laws, which are growing in number, or

climate strategies, among others, based on national and sub-national

context (medium conﬁdence). Effective and equitable climate

governance builds on engagement with civil society actors, political

actors, businesses, youth, labour, media, Indigenous Peoples and local

communities (medium conﬁdence). {WGIII SPM E.2.2, WGIII SPM E.3,

WGIII SPM E.3.1, WGIII SPM E.4.2, WGIII SPM E.4.3, WGIII SPM E.4.4}

The unit costs of several low-emission technologies, including

solar, wind and lithium-ion batteries, have fallen consistently

since 2010 (Figure 2.4). Design and process innovations in

combination with the use of digital technologies have led to

near-commercial availability of many low or zero emissions

options in buildings, transport and industry. From 2010-2019,

there have been sustained decreases in the unit costs of solar energy

(by 85%), wind energy (by 55%), and lithium-ion batteries (by 85%),

and large increases in their deployment, e.g., >10× for solar and >100× for

electric vehicles (EVs), albeit varying widely across regions (Figure 2.4).

Electricity from PV and wind is now cheaper than electricity from

fossil sources in many regions, electric vehicles are increasingly

competitive with internal combustion engines, and large-scale

battery storage on electricity grids is increasingly viable. In

comparison to modular small-unit size technologies, the empirical

record shows that multiple large-scale mitigation technologies, with

fewer opportunities for learning, have seen minimal cost reductions

and their adoption has grown slowly. Maintaining emission-intensive

systems may, in some regions and sectors, be more expensive than

transitioning to low emission systems. (high conﬁdence) {WGIII SPM B.4,

WGIII SPM B.4.1, WGIII SPM C.4.2, WGIII SPM C.5.2, WGIII SPM C.7.2,

WGIII SPM C.8, WGIII Figure SPM.3, WGIII Figure SPM.3}

For almost all basic materials – primary metals, building materials and

chemicals – many low- to zero-GHG intensity production processes are

at the pilot to near-commercial and in some cases commercial stage

but they are not yet established industrial practice. Integrated design

in construction and retroﬁt of buildings has led to increasing examples

of zero energy or zero carbon buildings. Technological innovation

made possible the widespread adoption of LED lighting. Digital

technologies including sensors, the internet of things, robotics, and

artiﬁcial intelligence can improve energy management in all sectors;

they can increase energy efﬁciency, and promote the adoption of many

low-emission technologies, including decentralised renewable energy,

while creating economic opportunities. However, some of these climate

change mitigation gains can be reduced or counterbalanced by growth in

demand for goods and services due to the use of digital devices. Several

mitigation options, notably solar energy, wind energy, electriﬁcation of

urban systems, urban green infrastructure, energy efﬁciency, demand

side management, improved forest- and crop/grassland management,

and reduced food waste and loss, are technically viable, are becoming

increasingly cost effective and are generally supported by the public, and

this enables expanded deployment in many regions. (high conﬁdence)

{WGIII SPM B.4.3, WGIII SPM C.5.2, WGIII SPM C.7.2, WGIII SPM E.1.1,

WGIII TS.6.5}

The magnitude of global climate ﬁnance ﬂows has increased

and ﬁnancing channels have broadened (high conﬁdence).

Annual tracked total ﬁnancial ﬂows for climate mitigation and

adaptation increased by up to 60% between 2013/14 and 2019/20,

but average growth has slowed since 2018 (medium conﬁdence) and

most climate ﬁnance stays within national borders (high conﬁdence).

Markets for green bonds, environmental, social and governance and

sustainable ﬁnance products have expanded signiﬁcantly since AR5

(high conﬁdence). Investors, central banks, and ﬁnancial regulators are

driving increased awareness of climate risk to support climate policy

development and implementation (high conﬁdence). Accelerated

international ﬁnancial cooperation is a critical enabler of low-GHG and

just transitions (high conﬁdence). {WGIII SPM B.5.4, WGIII SPM E.5,

WGIII TS.6.3, WGIII TS.6.4}

Economic instruments have been effective in reducing emissions,

complemented by regulatory instruments mainly at the national

and also sub-national and regional level (high conﬁdence). By 2020,

over 20% of global GHG emissions were covered by carbon taxes or

emissions trading systems, although coverage and prices have been

insufﬁcient to achieve deep reductions (medium conﬁdence). Equity and

distributional impacts of carbon pricing instruments can be addressed

by using revenue from carbon taxes or emissions trading to support

low-income households, among other approaches (high conﬁdence).

The mix of policy instruments which reduced costs and stimulated

adoption of solar energy, wind energy and lithium-ion batteries

includes public R&D, funding for demonstration and pilot projects, and

demand-pull instruments such as deployment subsidies to attain scale

(high conﬁdence) (Figure 2.4). {WGIII SPM B.4.1, WGIII SPM B.5.2,

WGIII SPM E.4.2, WG III TS.3}

Mitigation actions, supported by policies, have contributed

to a decrease in global energy and carbon intensity between

2010 and 2019, with a growing number of countries achieving

absolute GHG emission reductions for more than a decade (high

conﬁdence). While global net GHG emissions have increased since

2010, global energy intensity (total primary energy per unit GDP)

decreased by 2% yr

–1

between 2010 and 2019. Global carbon

intensity (CO

-FFI per unit primary energy) also decreased by 0.3%

–1

, mainly due to fuel switching from coal to gas, reduced expansion

of coal capacity, and increased use of renewables, and with large

regional variations over the same period. In many countries, policies

have enhanced energy efﬁciency, reduced rates of deforestation and

accelerated technology deployment, leading to avoided and in some

cases reduced or removed emissions (high conﬁdence). At least

18 countries have sustained production-based CO

and GHG and

consumption-based CO

absolute emission reductions for longer than

10 years since 2005 through energy supply decarbonization, energy

efﬁciency gains, and energy demand reduction, which resulted from

both policies and changes in economic structure (high conﬁdence).

Some countries have reduced production-based GHG emissions by a

third or more since peaking, and some have achieved reduction rates

of around 4% yr

–1

for several years consecutively (high conﬁdence).

Multiple lines of evidence suggest that mitigation policies have led to

avoided global emissions of several GtCO

-eq yr

–1

(medium conﬁdence).

Section 2

Section 1

Section 2

Market cost, with range

Adoption (note different scales)

Fossil fuel cost (2020)

Passenger

electric vehicle

Photovoltaics

(PV)

Onshore

wind

Offshore

wind

Key

a) Market Cost

b) Market Adoption

Renewable electricity generation

is increasingly price-competitive

and some sectors are electrifying

Since AR5, the unit costs of some

forms of renewable energy and

of batteries for passenger EVs

have fallen.

Since AR5, the installed capacity

of renewable energies has

increased multiple times.

2000 20202010

2010 2010 2010 2010

Cost ($2020/MWh)

1200

1600

Li-ion battery packs

800

400

150

300

450

600

Cost ($2020/kWh)

Adoption (millions of EVs)

Adoption (GW) -note differnt scales

200

400

600

800

Fossil fuel cost (2020)

below this point, costs can

be less than fossil fuels

Figure 2.4: Unit cost reductions and use in some rapidly changing mitigation technologies. The top panel (a) shows global costs per unit of energy (USD per MWh)

for some rapidly changing mitigation technologies. Solid blue lines indicate average unit cost in each year. Light blue shaded areas show the range between the 5th and 95th

percentiles in each year. Yellow shading indicates the range of unit costs for new fossil fuel (coal and gas) power in 2020 (corresponding to USD 55 to 148 per MWh).

In 2020, the levelised costs of energy (LCOE) of the three renewable energy technologies could compete with fossil fuels in many places. For batteries, costs shown are for 1 kWh

of battery storage capacity; for the others, costs are LCOE, which includes installation, capital, operations, and maintenance costs per MWh of electricity produced. The literature uses

LCOE because it allows consistent comparisons of cost trends across a diverse set of energy technologies to be made. However, it does not include the costs of grid integration

or climate impacts. Further, LCOE does not take into account other environmental and social externalities that may modify the overall (monetary and non-monetary) costs of

technologies and alter their deployment. The bottom panel (b) shows cumulative global adoption for each technology, in GW of installed capacity for renewable energy and

in millions of vehicles for battery-electric vehicles. A vertical dashed line is placed in 2010 to indicate the change over the past decade. The electricity production share reﬂects

different capacity factors; for example, for the same amount of installed capacity, wind produces about twice as much electricity as solar PV. Renewable energy and battery

technologies were selected as illustrative examples because they have recently shown rapid changes in costs and adoption, and because consistent data are available. Other

mitigation options assessed in the WGIII report are not included as they do not meet these criteria. {WGIII Figure SPM.3, WGIII 2.5, 6.4}

Current Status and Trends

Section 2

At least 1.8 GtCO

-eq yr

–1

of avoided emissions can be accounted for

by aggregating separate estimates for the effects of economic and

regulatory instruments (medium conﬁdence). Growing numbers of

laws and executive orders have impacted global emissions and are

estimated to have resulted in 5.9 GtCO

-eq yr

–1

of avoided emissions

in 2016 (medium conﬁdence). These reductions have only partly offset

global emissions growth (high confidence). {WGIII SPM B.1,

WGIII SPM B.2.4, WGIII SPM B.3.5, WGIII SPM B.5.1, WGIII SPM B.5.3,

WGIII 1.3.2, WGIII 2.2.3}

2.2.3. Adaptation Actions to Date

Progress in adaptation planning and implementation has been

observed across all sectors and regions, generating multiple

beneﬁts (very high conﬁdence). The ambition, scope and progress

on adaptation have risen among governments at the local, national and

international levels, along with businesses, communities and civil society

(high conﬁdence). Various tools, measures and processes are available

that can enable, accelerate and sustain adaptation implementation

(high conﬁdence). Growing public and political awareness of climate

impacts and risks has resulted in at least 170 countries and many cities

including adaptation in their climate policies and planning processes

(high conﬁdence). Decision support tools and climate services are

increasingly being used (very high conﬁdence) and pilot projects and

local experiments are being implemented in different sectors (high

conﬁdence). {WGII SPM C.1, WGII SPM.C.1.1, WGII TS.D.1.3, WGII TS.D.10}

Adaptation to water-related risks and impacts make up the majority (~60%)

of all documented

adaptation (high conﬁdence). A large number of

these adaptation responses are in the agriculture sector and these

include on-farm water management, water storage, soil moisture

conservation, and irrigation. Other adaptations in agriculture include

cultivar improvements, agroforestry, community-based adaptation and

farm and landscape diversiﬁcation among others (high conﬁdence).

For inland ﬂooding, combinations of non-structural measures like

early warning systems, enhancing natural water retention such as by

restoring wetlands and rivers, and land use planning such as no build

zones or upstream forest management, can reduce ﬂood risk (medium

conﬁdence). Some land-related adaptation actions such as sustainable

food production, improved and sustainable forest management,

soil organic carbon management, ecosystem conservation and land

restoration, reduced deforestation and degradation, and reduced

food loss and waste are being undertaken, and can have mitigation

co-beneﬁts (high conﬁdence). Adaptation actions that increase the

resilience of biodiversity and ecosystem services to climate change

include responses like minimising additional stresses or disturbances,

reducing fragmentation, increasing natural habitat extent, connectivity

and heterogeneity, and protecting small-scale refugia where

microclimate conditions can allow species to persist (high conﬁdence).

Most innovations in urban adaptation have occurred through advances

Documented adaptation refers to published literature on adaptation policies, measures and actions that has been implemented and documented in peer reviewed literature, as

opposed to adaptation that may have been planned, but not implemented.

Effectiveness refers here to the extent to which an adaptation option is anticipated or observed to reduce climate-related risk.

See Annex I: Glossary.

Irrigation is effective in reducing drought risk and climate impacts in many regions and has several livelihood beneﬁts, but needs appropriate management to avoid potential

adverse outcomes, which can include accelerated depletion of groundwater and other water sources and increased soil salinization (medium conﬁdence).

EbA is recognised internationally under the Convention on Biological Diversity (CBD14/5). A related concept is Nature-based Solutions (NbS), see Annex I: Glossary.

in disaster risk management, social safety nets and green/blue

infrastructure (medium conﬁdence). Many adaptation measures that

beneﬁt health and well-being are found in other sectors (e.g., food,

livelihoods, social protection, water and sanitation, infrastructure)

(high conﬁdence). {WGII SPM C.2.1, WGII SPM C.2.2, WGII TS.D.1.2,

WGII TS.D.1.4, WGII TS.D.4.2, WGII TS.D.8.3, WGII 4 ES; SRCCL SPM B.1.1}

Adaptation can generate multiple additional beneﬁts such as improving

agricultural productivity, innovation, health and well-being, food

security, livelihood, and biodiversity conservation as well as reduction

of risks and damages (very high conﬁdence). {WGII SPM C1.1}

Globally tracked adaptation ﬁnance has shown an upward trend

since AR5, but represents only a small portion of total climate

ﬁnance, is uneven and has developed heterogeneously across

regions and sectors (high conﬁdence). Adaptation ﬁnance has come

predominantly from public sources, largely through grants, concessional

and non-concessional instruments (very high conﬁdence). Globally,

private-sector ﬁnancing of adaptation from a variety of sources such

as commercial ﬁnancial institutions, institutional investors, other

private equity, non-ﬁnancial corporations, as well as communities

and households has been limited, especially in developing countries

(high conﬁdence). Public mechanisms and ﬁnance can leverage

private sector ﬁnance for adaptation by addressing real and perceived

regulatory, cost and market barriers, for example via public-private

partnerships (high conﬁdence). Innovations in adaptation and

resilience ﬁnance, such as forecast-based/anticipatory ﬁnancing

systems and regional risk insurance pools, have been piloted and are

growing in scale (high conﬁdence). {WGII SPM C.3.2, WGII SPM C.5.4;

WGII TS.D.1.6, WGII Cross-Chapter Box FINANCE; WGIII SPM E.5.4}

There are adaptation options which are effective

in reducing

climate risks

for speciﬁc contexts, sectors and regions and

contribute positively to sustainable development and other

societal goals. In the agriculture sector, cultivar improvements,

on-farm water management and storage, soil moisture conservation,

irrigation

, agroforestry, community-based adaptation, and farm and

landscape level diversiﬁcation, and sustainable land management

approaches, provide multiple beneﬁts and reduce climate risks.

Reduction of food loss and waste, and adaptation measures in support

of balanced diets contribute to nutrition, health, and biodiversity beneﬁts.

(high conﬁdence) {WGII SPM C.2, WGII SPM C.2.1, WGII SPM C.2.2;

SRCCL B.2, SRCCL SPM C.2.1}

Ecosystem-based Adaptation

approaches such as urban greening,

restoration of wetlands and upstream forest ecosystems reduce

a range of climate change risks, including ﬂood risks, urban heat

and provide multiple co-beneﬁts. Some land-based adaptation

options provide immediate beneﬁts (e.g., conservation of peatlands,

Section 2

Section 1

Section 2

wetlands, rangelands, mangroves and forests); while afforestation and

reforestation, restoration of high-carbon ecosystems, agroforestry, and

the reclamation of degraded soils take more time to deliver measurable

results. Signiﬁcant synergies exist between adaptation and mitigation,

for example through sustainable land management approaches.

Agroecological principles and practices and other approaches

that work with natural processes support food security, nutrition,

health and well-being, livelihoods and biodiversity, sustainability and

ecosystem services. (high conﬁdence) {WGII SPM C.2.1, WGII SPM C.2.2,

WGII SPM C.2.5, WGII TS.D.4.1; SRCCL SPM B.1.2, SRCCL SPM.B.6.1;

SROCC SPM C.2}

Combinations of non-structural measures like early warning systems

and structural measures like levees have reduced loss of lives in case

of inland ﬂooding (medium conﬁdence) and early warning systems

along with ﬂood-prooﬁng of buildings have proven to be cost-effective

in the context of coastal ﬂooding under current sea level rise (high

conﬁdence). Heat Health Action Plans that include early warning and

response systems are effective adaptation options for extreme heat

(high conﬁdence). Effective adaptation options for water, food and

vector-borne diseases include improving access to potable water,

reducing exposure of water and sanitation systems to extreme weather

events, and improved early warning systems, surveillance, and vaccine

development (very high conﬁdence). Adaptation options such as

disaster risk management, early warning systems, climate services

and social safety nets have broad applicability across multiple sectors

(high conﬁdence). {WGII SPM C.2.1, WGII SPM C.2.5, WGII SPM C.2.9,

WGII SPM C.2.11, WGII SPM C.2.13; SROCC SPM C.3.2}

Integrated, multi-sectoral solutions that address social inequities,

differentiate responses based on climate risk and cut across systems,

increase the feasibility and effectiveness of adaptation in multiple

sectors (high conﬁdence). {WGII SPM C.2}

Current Status and Trends

Section 2

2.3 Current Mitigation and Adaptation Actions and Policies are not Sufﬁcient

At the time of the present assessment

there are gaps between global ambitions and the sum of declared

national ambitions. These are further compounded by gaps between declared national ambitions and current

implementation for all aspects of climate action. For mitigation, global GHG emissions in 2030 implied by NDCs

announced by October 2021 would make it likely that warming will exceed 1.5°C during the 21st century and would

make it harder to limit warming below 2°C.

Despite progress, adaptation gaps

persist, with many initiatives

prioritising short-term risk reduction, hindering transformational adaptation. Hard and soft limits to adaptation

are being reached in some sectors and regions, while maladaptation is also increasing and disproportionately

affecting vulnerable groups. Systemic barriers such as funding, knowledge, and practice gaps, including lack of

climate literacy and data hinders adaptation progress. Insufﬁcient ﬁnancing, especially for adaptation, constraints

climate action in particular in developing countries. (high conﬁdence)

The timing of various cut-offs for assessment differs by WG report and the aspect assessed. See footnote 1 in Section 1.

See CSB.2 for a discussion of scenarios and pathways.

See Annex I: Glossary.

2.3.1. The Gap Between Mitigation Policies, Pledges and

Pathways that Limit Warming to 1.5°C or Below 2°C

Global GHG emissions in 2030 associated with the implementation

of NDCs announced prior to COP26

would make it likely that

warming will exceed 1.5°C during the 21st century and would

make it harder to limit warming below 2°C – if no additional

commitments are made or actions taken (Figure 2.5, Table 2.2).

A substantial ‘emissions gap’ exists as global GHG emissions in 2030

associated with the implementation of NDCs announced prior to COP26

would be similar to or only slightly below 2019 emission levels and

higher than those associated with modelled mitigation pathways that

limit warming to 1.5°C (>50%) with no or limited overshoot or to

2°C (>67%), assuming immediate action, which implies deep, rapid,

and sustained global GHG emission reductions this decade (high

conﬁdence) (Table 2.2, Table 3.1, 4.1).

The magnitude of the emissions

gap depends on the global warming level considered and whether only

unconditional or also conditional elements of NDCs

are considered

(high conﬁdence) (Table 2.2). Modelled pathways that are consistent

with NDCs announced prior to COP26 until 2030 and assume no

increase in ambition thereafter have higher emissions, leading

The timing of various cut-offs for assessment differs by WG report and the aspect assessed. See footnote 58 in Section 1.

See CSB.2 for a discussion of scenarios and pathways.

See Annex I: Glossary.

NDCs announced prior to COP26 refer to the most recent NDCs submitted to the UNFCCC up to the literature cut-off date of the WGIII report, 11 October 2021, and revised

NDCs announced by China, Japan and the Republic of Korea prior to October 2021 but only submitted thereafter. 25 NDC updates were submitted between 12 October 2021

and the start of COP26. {WGIII SPM footnote 24}

Immediate action in modelled global pathways refers to the adoption between 2020 and at latest before 2025 of climate policies intended to limit global warming to a given

level. Modelled pathways that limit warming to 2°C (>67%) based on immediate action are summarised in category C3a in Table 3.1. All assessed modelled global pathways

that limit warming to 1.5°C (>50%) with no or limited overshoot assume immediate action as deﬁned here (Category C1 in Table 3.1). {WGIII SPM footnote 26}

In this report, ‘unconditional’ elements of NDCs refer to mitigation efforts put forward without any conditions. ‘Conditional’ elements refer to mitigation efforts that are

contingent on international cooperation, for example bilateral and multilateral agreements, ﬁnancing or monetary and/or technological transfers. This terminology is used in the

literature and the UNFCCC’s NDC Synthesis Reports, not by the Paris Agreement. {WGIII SPM footnote 27}

Implementation gaps refer to how far currently enacted policies and actions fall short of reaching the pledges. The policy cut-off date in studies used to project GHG emissions

of ‘policies implemented by the end of 2020’ varies between July 2019 and November 2020. {WGIII Table 4.2, WGIII SPM footnote 25}

to a median global warming of 2.8 [2.1 to 3.4]°C by 2100 (medium

conﬁdence). If the ‘emission gap’ is not reduced, global GHG emissions

in 2030 consistent with NDCs announced prior to COP26 make it likely

that warming will exceed 1.5°C during the 21st century, while limiting

warming to 2°C (>67%) would imply an unprecedented acceleration of

mitigation efforts during 2030–2050 (medium conﬁdence) (see Section 4.1,

Cross-Section Box.2). {WGIII SPM B.6, WGIII SPM B.6.1, WGIII SPM B.6.3,

WGIII SPM B.6.4, WGIII SPM C.1.1}

Policies implemented by the end of 2020 are projected to result in

higher global GHG emissions in 2030 than those implied by NDCs,

indicating an ‘implementation gap

’ (high conﬁdence) (Table 2.2,

Figure 2.5). Projected global emissions implied by policies implemented

by the end of 2020 are 57 (52–60) GtCO

-eq in 2030 (Table 2.2). This

points to an implementation gap compared with the NDCs of 4 to

7 GtCO

-eq in 2030 (Table 2.2); without a strengthening of policies,

emissions are projected to rise, leading to a median global warming

of 2.2°C to 3.5°C (very likely range) by 2100 (medium confidence)

(see Section 3.1.1). {WGIII SPM B.6.1, WGIII SPM C.1}

Section 2

Section 1

Section 2

Projected cumulative future CO

emissions over the lifetime of existing

fossil fuel infrastructure without additional abatement

exceed the

total cumulative net CO

emissions in pathways that limit warming to

1.5°C (>50%) with no or limited overshoot. They are approximately

equal to total cumulative net CO

emissions in pathways that limit

warming to 2°C with a likelihood of 83%

(see Figure 3.5). Limiting

warming to 2°C (>67%) or lower will result in stranded assets.

About 80% of coal, 50% of gas, and 30% of oil reserves cannot be

burned and emitted if warming is limited to 2°C. Signiﬁcantly more

reserves are expected to remain unburned if warming is limited to

1.5°C. (high conﬁdence) {WGIII SPM B.7, WGIII Box 6.3}

Abatement here refers to human interventions that reduce the amount of GHGs that are released from fossil fuel infrastructure to the atmosphere. {WGIII SPM footnote 34}

WGI provides carbon budgets that are in line with limiting global warming to temperature limits with different likelihoods, such as 50%, 67% or 83%. {WGI Table SPM.2}

Table 2.2 Projected global emissions in 2030 associated with policies implemented by the end of 2020 and NDCs announced prior to COP26, and associated

emissions gaps. Emissions projections for 2030 and gross differences in emissions are based on emissions of 52–56 GtCO

-eq yr–1 in 2019 as assumed in underlying model

studies

. (medium conﬁdence) {WGIII Table SPM.1} (Table 3.1, Cross-Section Box.2)

Abatement here refers to human interventions that reduce the amount of GHGs that are released from fossil fuel infrastructure to the atmosphere. {WGIII SPM footnote 34}

WGI provides carbon budgets that are in line with limiting global warming to temperature limits with different likelihoods, such as 50%, 67% or 83%. {WGI Table SPM.2}

The 2019 range of harmonised GHG emissions across the pathways [53–58 GtCO

-eq] is within the uncertainty ranges of 2019 emissions assessed in WGIII Chapter 2 [53–66 GtCO

-eq].

Emission and implementation gaps associated with projected

global emissions in 2030 under Nationally Determined

Contributions (NDCs) and implemented policies

Implied by policies

implemented by the end

of 2020 (GtCO

-eq/yr)

Implied by Nationally Determined Contributions

(NDCs) announced prior to COP26

Unconditional

elements (GtCO

-eq/yr)

Including conditional

elements (GtCO

-eq/yr)

Median projected global emissions

(min–max)*

Implementation gap between

implemented policies and NDCs

(median)

Emissions gap between NDCs and

pathways that limit warming to

2°C (>67%) with immediate action

Emissions gap between NDCs and

pathways that limit warming to

1.5°C (>50%) with no or limited

overshoot with immediate action

57 [52–60]

–

4 7

53 [50–57] 50 [47–55]

10–16 6–14

19–26 16–23

Emissions projections for 2030 and gross differences in emissions are based on emissions of 52–56 GtCO

-eq/yr in 2019 as assumed in underlying model studies. (

medium conﬁdence

)

Current Status and Trends

Section 2

a) Global GHG emissions b) 2030

GHG emissions (GtCO

-eq/yr)

2020 202520152010 2030 2035 2040 2045 2050

Limit warming to 2ºC (>67%)

or 1.5 (>50%) after high

overshoot with NDCs until 2030

Trend from implemented policies

2019

Limit warming to

1.5ºC (>50%) with

no or limited overshoot

Limit warming

to 2ºC (>67%)

to be on-track to limit

warming to 1.5°C,

we need much more

reduction by 2030

-4%

+5%

-26%

-43%

Projected global GHG emissions from NDCs announced prior to

COP26 would make it likely that warming will exceed 1.5°C and

also make it harder after 2030 to limit warming to below 2°C

Past GHG emissions and

uncertainty for 2015 and 2019

(dot indicates the median)

Past GHG emissions and

uncertainty for 2015 and 2019

(dot indicates the median)

Figure 2.5 Global GHG emissions of modelled pathways (funnels in Panel a), and projected emission outcomes from near-term policy assessments for 2030 (Panel b).

Panel a shows global GHG emissions over 2015-2050 for four types of assessed modelled global pathways:

- Trend from implemented policies: Pathways with projected near-term GHG emissions in line with policies implemented until the end of 2020 and extended with comparable

ambition levels beyond 2030 (29 scenarios across categories C5–C7, WGIII Table SPM.2).

- Limit to 2°C (>67%) or return warming to 1.5°C (>50%) after a high overshoot, NDCs until 2030: Pathways with GHG emissions until 2030 associated with the

implementation of NDCs announced prior to COP26, followed by accelerated emissions reductions likely to limit warming to 2°C (C3b, WGIII Table SPM.2) or to return

warming to 1.5°C with a probability of 50% or greater after high overshoot (subset of 42 scenarios from C2, WGIII Table SPM.2).

- Limit to 2°C (>67%) with immediate action: Pathways that limit warming to 2°C (>67%) with immediate action after 2020 (C3a, WGIII Table SPM.2).

- Limit to 1.5°C (>50%) with no or limited overshoot: Pathways limiting warming to 1.5°C with no or limited overshoot (C1, WGIII Table SPM.2 C1).

All these pathways assume immediate action after 2020. Past GHG emissions for 2010-2015 used to project global warming outcomes of the modelled pathways are shown by a

black line. Panel b shows a snapshot of the GHG emission ranges of the modelled pathways in 2030 and projected emissions outcomes from near-term policy assessments in 2030

from WGIII Chapter 4.2 (Tables 4.2 and 4.3; median and full range). GHG emissions are CO

-equivalent using GWP100 from AR6 WGI. {WGIII Figure SPM.4, WGIII 3.5, 4.2, Table 4.2,

Table 4.3, Cross-Chapter Box 4 in Chapter 4} (Table 3.1, Cross-Section Box.2)

Section 2

Section 1

Section 2

Cross-Section Box.1: Understanding Net Zero CO

and Net Zero GHG Emissions

Limiting human-caused global warming to a speciﬁc level requires limiting cumulative CO

emissions, reaching net zero or net negative

emissions, along with strong reductions in other GHG emissions (see 3.3.2). Future additional warming will depend on future emissions,

with total warming dominated by past and future cumulative CO

emissions. {WGI SPM D.1.1, WGI Figure SPM.4; SR1.5 SPM A.2.2}

Reaching net zero CO

emissions is different from reaching net zero GHG emissions. The timing of net zero for a basket of GHGs depends

on the emissions metric, such as global warming potential over a 100-year period, chosen to convert non-CO

emissions into CO

-equivalent (high

conﬁdence). However, for a given emissions pathway, the physical climate response is independent of the metric chosen (high conﬁdence).

{WGI SPM D.1.8; WGIII Box TS.6, WGIII Cross-Chapter Box 2}

Achieving global net zero GHG emissions requires all remaining CO

and metric-weighted

non-CO

GHG emissions to be

counterbalanced by durably stored CO

removals (high conﬁdence). Some non-CO

emissions, such as CH

and N

O from agriculture,

cannot be fully eliminated using existing and anticipated technical measures. {WGIII SPM C.2.4, WGIII SPM C.11.4, WGIII Cross-Chapter Box 3}

Global net zero CO

or GHG emissions can be achieved even if some sectors and regions are net emitters, provided that

others reach net negative emissions (see Figure 4.1). The potential and cost of achieving net zero or even net negative emissions

vary by sector and region. If and when net zero emissions for a given sector or region are reached depends on multiple factors, including

the potential to reduce GHG emissions and undertake carbon dioxide removal, the associated costs, and the availability of policy

mechanisms to balance emissions and removals between sectors and countries. (high conﬁdence) {WGIII Box TS.6, WGIII Cross-Chapter Box 3}

The adoption and implementation of net zero emission targets by countries and regions also depend on equity and capacity

considerations (high conﬁdence). The formulation of net zero pathways by countries will beneﬁt from clarity on scope, plans-of-action, and

fairness. Achieving net zero emission targets relies on policies, institutions, and milestones against which to track progress. Least-cost global

modelled pathways have been shown to distribute the mitigation effort unevenly, and the incorporation of equity principles could change the

country-level timing of net zero (high conﬁdence). The Paris Agreement also recognizes that peaking of emissions will occur later in developing

countries than developed countries (Article 4.1). {WGIII Box TS.6, WGIII Cross-Chapter Box 3, WGIII 14.3}

More information on country-level net zero pledges is provided in Section 2.3.1, on the timing of global net zero emissions in Section 3.3.2, and

on sectoral aspects of net zero in Section 4.1.

See footnote 12 above.

Current Status and Trends

Section 2

Many countries have signalled an intention to achieve net

zero GHG or net zero CO

emissions by around mid-century

(Cross-Section Box.1). More than 100 countries have either adopted,

announced or are discussing net zero GHG or net zero CO

emissions

commitments, covering more than two-thirds of global GHG emissions.

A growing number of cities are setting climate targets, including net zero

GHG targets. Many companies and institutions have also announced

net zero emissions targets in recent years. The various net zero emission

pledges differ across countries in terms of scope and speciﬁcity, and

limited policies are to date in place to deliver on them. {WGIII SPM C.6.4,

WGIII TS.4.1, WGIII Table TS.1, WGIII 13.9, WGIII 14.3, WGIII 14.5}

All mitigation strategies face implementation challenges,

including technology risks, scaling, and costs (high conﬁdence).

Almost all mitigation options also face institutional barriers that

need to be addressed to enable their application at scale (medium

conﬁdence). Current development pathways may create behavioural,

spatial, economic and social barriers to accelerated mitigation at all

scales (high conﬁdence). Choices made by policymakers, citizens, the

private sector and other stakeholders inﬂuence societies’ development

pathways (high conﬁdence). Structural factors of national circumstances

and capabilities (e.g., economic and natural endowments, political

systems and cultural factors and gender considerations) affect the

breadth and depth of climate governance (medium conﬁdence). The

extent to which civil society actors, political actors, businesses, youth,

labour, media, Indigenous Peoples, and local communities are engaged

inﬂuences political support for climate change mitigation and eventual

policy outcomes (medium conﬁdence). {WGIII SPM C.3.6, WGIII SPM E.1.1,

WGIII SPM E.2.1, WGIII SPM E.3.3}

The adoption of low-emission technologies lags in most

developing countries, particularly least developed ones,

due in part to weaker enabling conditions, including limited

ﬁnance, technology development and transfer, and capacity

(medium conﬁdence). In many countries, especially those with

limited institutional capacity, several adverse side-effects have

been observed as a result of diffusion of low-emission technology,

e.g., low-value employment, and dependency on foreign knowledge

and suppliers (medium conﬁdence). Low-emission innovation along

with strengthened enabling conditions can reinforce development

beneﬁts, which can, in turn, create feedbacks towards greater public

support for policy (medium conﬁdence). Persistent and region-speciﬁc

barriers also continue to hamper the economic and political feasibility

of deploying AFOLU mitigation options (medium conﬁdence). Barriers to

implementation of AFOLU mitigation include insufﬁcient institutional and

ﬁnancial support, uncertainty over long-term additionality and trade-offs,

weak governance, insecure land ownership, low incomes and the lack

of access to alternative sources of income, and the risk of reversal (high

conﬁdence). {WGIII SPM B.4.2, WGIII SPM C.9.1, WGIII SPM C.9.3}

See Annex I: Glossary.

100

Adaptation limit: The point at which an actor’s objectives (or system needs) cannot be secured from intolerable risks through adaptive actions. Hard adaptation limit

- No adaptive actions are possible to avoid intolerable risks. Soft adaptation limit - Options are currently not available to avoid intolerable risks through adaptive action.

101

Maladaptation refers to actions that may lead to increased risk of adverse climate-related outcomes, including via increased greenhouse gas emissions, increased or shifted vulnerability

to climate change, more inequitable outcomes, or diminished welfare, now or in the future. Most often, maladaptation is an unintended consequence. See Annex I: Glossary.

2.3.2. Adaptation Gaps and Barriers

Despite progress, adaptation gaps exist between current

levels of adaptation and levels needed to respond to impacts

and reduce climate risks (high conﬁdence). While progress in

adaptation implementation is observed across all sectors and regions

(very high conﬁdence), many adaptation initiatives prioritise immediate

and near-term climate risk reduction, e.g., through hard ﬂood protection,

which reduces the opportunity for transformational adaptation

(high

conﬁdence). Most observed adaptation is fragmented, small in scale,

incremental, sector-speciﬁc, and focused more on planning rather than

implementation (high conﬁdence). Further, observed adaptation is

unequally distributed across regions and the largest adaptation gaps

exist among lower population income groups (high conﬁdence). In the

urban context, the largest adaptation gaps exist in projects that manage

complex risks, for example in the food–energy–water–health nexus or

the inter-relationships of air quality and climate risk (high conﬁdence).

Many funding, knowledge and practice gaps remain for effective

implementation, monitoring and evaluation and current adaptation

efforts are not expected to meet existing goals (high conﬁdence).

At current rates of adaptation planning and implementation the

adaptation gap will continue to grow (high conﬁdence). {WGII SPM C.1,

WGII SPM C.1.2, WGII SPM C.4.1, WGII TS.D.1.3, WGII TS.D.1.4}

Soft and hard adaptation limits

100

have already been reached in

some sectors and regions, in spite of adaptation having buffered

some climate impacts (high conﬁdence). Ecosystems already

reaching hard adaptation limits include some warm water coral reefs,

some coastal wetlands, some rainforests, and some polar and mountain

ecosystems (high conﬁdence). Individuals and households in low lying

coastal areas in Australasia and Small Islands and smallholder farmers

in Central and South America, Africa, Europe and Asia have reached

soft limits (medium conﬁdence), resulting from ﬁnancial, governance,

institutional and policy constraints and can be overcome by addressing

these constraints (high conﬁdence). Transitioning from incremental to

transformational adaptation can help overcome soft adaptation limits

(high conﬁdence). {WGII SPM C.3, WGII SPM C.3.1, WGII SPM C.3.2,

WGII SPM C.3.3, WGII SPM.C.3.4, WGII 16 ES}

Adaptation does not prevent all losses and damages, even with

effective adaptation and before reaching soft and hard limits. Losses

and damages are unequally distributed across systems, regions and

sectors and are not comprehensively addressed by current ﬁnancial,

governance and institutional arrangements, particularly in vulnerable

developing countries. (high conﬁdence) {WGII SPM.C.3.5}

There is increased evidence of maladaptation

101

in various sectors

and regions. Examples of maladaptation are observed in urban areas

(e.g., new urban infrastructure that cannot be adjusted easily or affordably),

agriculture (e.g., using high-cost irrigation in areas projected to have more

intense drought conditions), ecosystems (e.g. ﬁre suppression in naturally

Section 2

Section 1

Section 2

ﬁre-adapted ecosystems, or hard defences against ﬂooding) and human

settlements (e.g. stranded assets and vulnerable communities that

cannot afford to shift away or adapt and require an increase in social

safety nets). Maladaptation especially affects marginalised and vulnerable

groups adversely (e.g., Indigenous Peoples, ethnic minorities, low-income

households, people living in informal settlements), reinforcing and

entrenching existing inequities. Maladaptation can be avoided by ﬂexible,

multi-sectoral, inclusive and long-term planning and implementation of

adaptation actions with beneﬁts to many sectors and systems. (high

conﬁdence) {WGII SPM C.4, WGII SPM C.4.3, WGII TS.D.3.1}

Systemic barriers constrain the implementation of adaptation

options in vulnerable sectors, regions and social groups (high

conﬁdence). Key barriers include limited resources, lack of private-sector

and civic engagement, insufﬁcient mobilisation of ﬁnance, lack of political

commitment, limited research and/or slow and low uptake of adaptation

science and a low sense of urgency. Inequity and poverty also constrain

adaptation, leading to soft limits and resulting in disproportionate

exposure and impacts for most vulnerable groups (high conﬁdence). The

largest adaptation gaps exist among lower income population groups

(high conﬁdence). As adaptation options often have long implementation

times, long-term planning and accelerated implementation, particularly

in this decade, is important to close adaptation gaps, recognising that

constraints remain for some regions (high conﬁdence). Prioritisation of

options and transitions from incremental to transformational adaptation

are limited due to vested interests, economic lock-ins, institutional

path dependencies and prevalent practices, cultures, norms and belief

systems (high conﬁdence). Many funding, knowledge and practice

gaps remain for effective implementation, monitoring and evaluation

of adaptation (high conﬁdence), including, lack of climate literacy at

all levels and limited availability of data and information (medium

conﬁdence); for example for Africa, severe climate data constraints and

inequities in research funding and leadership reduce adaptive capacity

(very high conﬁdence). {WGII SPM C.1.2, WGII SPM C.3.1, WGII TS.D.1.3,

WGII TS.D.1.5, WGII TS.D.2.4}

2.3.3. Lack of Finance as a Barrier to Climate Action

Insufﬁcient ﬁnancing, and a lack of political frameworks and

incentives for ﬁnance, are key causes of the implementation

gaps for both mitigation and adaptation (high conﬁdence).

Financial ﬂows remained heavily focused on mitigation, are

uneven, and have developed heterogeneously across regions

and sectors (high conﬁdence). In 2018, public and publicly mobilised

private climate ﬁnance ﬂows from developed to developing countries

were below the collective goal under the UNFCCC and Paris Agreement

to mobilise USD 100 billion per year by 2020 in the context of

meaningful mitigation action and transparency on implementation

(medium conﬁdence). Public and private ﬁnance ﬂows for fossil fuels

are still greater than those for climate adaptation and mitigation (high

conﬁdence). The overwhelming majority of tracked climate ﬁnance

is directed towards mitigation (very high conﬁdence). Nevertheless,

average annual modelled investment requirements for 2020 to 2030

in scenarios that limit warming to 2°C or 1.5°C are a factor of three

to six greater than current levels, and total mitigation investments

(public, private, domestic and international) would need to increase

across all sectors and regions (medium conﬁdence). Challenges

remain for green bonds and similar products, in particular around

integrity and additionality, as well as the limited applicability of

these markets to many developing countries (high confidence).

{WGII SPM C.3.2, WGII SPM C.5.4; WGIII SPM B.5.4, WGIII SPM E.5.1}

Current global ﬁnancial ﬂows for adaptation including from public

and private ﬁnance sources, are insufﬁcient for and constrain

implementation of adaptation options, especially in developing

countries (high conﬁdence). There are widening disparities between

the estimated costs of adaptation and the documented ﬁnance

allocated to adaptation (high conﬁdence). Adaptation ﬁnance

needs are estimated to be higher than those assessed in AR5, and

the enhanced mobilisation of and access to ﬁnancial resources are

essential for implementation of adaptation and to reduce adaptation

gaps (high conﬁdence). Annual ﬁnance ﬂows targeting adaptation for

Africa, for example, are billions of USD less than the lowest adaptation

cost estimates for near-term climate change (high conﬁdence). Adverse

climate impacts can further reduce the availability of ﬁnancial resources

by causing losses and damages and impeding national economic

growth, thereby further increasing ﬁnancial constraints for adaptation

particularly for developing countries and LDCs (medium conﬁdence).

{WGII SPM C.1.2, WGII SPM C.3.2, WGII SPM C.5.4, WGII TS.D.1.6}

Without effective mitigation and adaptation, losses and damages will

continue to disproportionately affect the poorest and most vulnerable

populations. Accelerated ﬁnancial support for developing countries

from developed countries and other sources is a critical enabler to

enhance mitigation action {WGIII SPM. E.5.3}. Many developing

countries lack comprehensive data at the scale needed and lack adequate

ﬁnancial resources needed for adaptation for reducing associated

economic and non-economic losses and damages. (high conﬁdence)

{WGII Cross-Chapter Box LOSS, WGII SPM C.3.1, WGII SPM C.3.2,

WGII TS.D.1.3, WGII TS.D.1.5; WGIII SPM E.5.3}

There are barriers to redirecting capital towards climate action both

within and outside the global ﬁnancial sector. These barriers include:

the inadequate assessment of climate-related risks and investment

opportunities, regional mismatch between available capital and

investment needs, home bias factors, country indebtedness levels,

economic vulnerability, and limited institutional capacities. Challenges

from outside the ﬁnancial sector include: limited local capital markets;

unattractive risk-return proﬁles, in particular due to missing or weak

regulatory environments that are inconsistent with ambition levels;

limited institutional capacity to ensure safeguards; standardisation,

aggregation, scalability and replicability of investment opportunities

and ﬁnancing models; and, a pipeline ready for commercial investments.

(high conﬁdence) {WGII SPM C.5.4; WGIII SPM E.5.2; SR1.5 SPM D.5.2}

Current Status and Trends

Section 2

Cross-Section Box.2: Scenarios, Global Warming Levels, and Risks

Modelled scenarios and pathways

102

are used to explore future emissions, climate change, related impacts and risks, and possible mitigation and

adaptation strategies and are based on a range of assumptions, including socio-economic variables and mitigation options. These are quantitative

projections and are neither predictions nor forecasts. Global modelled emission pathways, including those based on cost effective approaches

contain regionally differentiated assumptions and outcomes, and have to be assessed with the careful recognition of these assumptions. Most

do not make explicit assumptions about global equity, environmental justice or intra-regional income distribution. IPCC is neutral with regard

to the assumptions underlying the scenarios in the literature assessed in this report, which do not cover all possible futures

103

. {WGI Box SPM.1;

WGII Box SPM.1; WGIII Box SPM.1; SROCC Box SPM.1; SRCCL Box SPM.1}

Socio-economic Development, Scenarios, and Pathways

The ﬁve Shared Socio-economic Pathways (SSP1 to SSP5) were designed to span a range of challenges to climate change mitigation and adaptation.

For the assessment of climate impacts, risk and adaptation, the SSPs are used for future exposure, vulnerability and challenges to adaptation.

Depending on levels of GHG mitigation, modelled emissions scenarios based on the SSPs can be consistent with low or high warming levels

104

There are many different mitigation strategies that could be consistent with different levels of global warming in 2100 (see Figure 4.1).

{WGI Box SPM.1; WGII Box SPM.1; WGIII Box SPM.1, WGIII Box TS.5, WGIII Annex III; SRCCL Box SPM.1, SRCCL Figure SPM.2}

WGI assessed the climate response to ﬁve illustrative scenarios based on SSPs

105

that cover the range of possible future development of anthropogenic

drivers of climate change found in the literature. These scenarios combine socio-economic assumptions, levels of climate mitigation, land use and

air pollution controls for aerosols and non-CH

ozone precursors. The high and very high GHG emissions scenarios (SSP3-7.0 and SSP5-8.5) have

emissions that roughly double from current levels by 2100 and 2050, respectively

106

. The intermediate GHG emissions scenario (SSP2-4.5)

has CO

emissions remaining around current levels until the middle of the century. The very low and low GHG emissions scenarios (SSP1-1.9 and

SSP1-2.6) have CO

emissions declining to net zero around 2050 and 2070, respectively, followed by varying levels of net negative CO

emissions. In addition, Representative Concentration Pathways (RCPs)

107

were used by WGI and WGII to assess regional climate changes,

impacts and risks. {WGI Box SPM.1} (Cross-Section Box.2 Figure 1)

In WGIII, a large number of global modelled emissions pathways were assessed, of which 1202 pathways were categorised based on their

projected global warming over the 21st century, with categories ranging from pathways that limit warming to 1.5°C with more than 50%

likelihood

108

with no or limited overshoot (C1) to pathways that exceed 4°C (C8). Methods to project global warming associated with the

modelled pathways were updated to ensure consistency with the AR6 WGI assessment of the climate system response

109

. {WGIII Box SPM.1,WGIII

Table 3.1} (Table 3.1, Cross-Section Box.2 Figure 1)

102

In the literature, the terms pathways and scenarios are used interchangeably, with the former more frequently used in relation to climate goals. WGI primarily used the term

scenarios and WGIII mostly used the term modelled emissions and mitigation pathways. The SYR primarily uses scenarios when referring to WGI and modelled emissions and

mitigation pathways when referring to WGIII. {WGI Box SPM.1; WGIII footnote 44}

103

Around half of all modelled global emissions pathways assume cost-effective approaches that rely on least-cost mitigation/abatement options globally. The other half look

at existing policies and regionally and sectorally differentiated actions. The underlying population assumptions range from 8.5 to 9.7 billion in 2050 and 7.4 to 10.9 billion

in 2100 (5–95th percentile) starting from 7.6 billion in 2019. The underlying assumptions on global GDP growth range from 2.5 to 3.5% per year in the 2019–2050 period

and 1.3 to 2.1% per year in the 2050–2100 (5–95th percentile). {WGIII Box SPM.1}

104

High mitigation challenges, for example, due to assumptions of slow technological change, high levels of global population growth, and high fragmentation as in the Shared

Socio-economic Pathway SSP3, may render modelled pathways that limit warming to 2°C (> 67%) or lower infeasible (medium conﬁdence). {WGIII SPM C.1.4; SRCCL Box SPM.1}

105

SSP-based scenarios are referred to as SSPx-y, where ‘SSPx’ refers to the Shared Socio-economic Pathway describing the socioeconomic trends underlying the scenarios, and

‘y’ refers to the level of radiative forcing (in watts per square metre, or Wm

–2

) resulting from the scenario in the year 2100. {WGI SPM footnote 22}

106

Very high emission scenarios have become less likely but cannot be ruled out. Temperature levels > 4°C may result from very high emission scenarios, but can also occur from

lower emission scenarios if climate sensitivity or carbon cycle feedbacks are higher than the best estimate. {WGIII SPM C.1.3}

107

RCP-based scenarios are referred to as RCPy, where ‘y’ refers to the approximate level of radiative forcing (in watts per square metre, or Wm

–2

) resulting from the scenario in the

year 2100. {WGII SPM footnote 21}

108

Denoted ‘>50%’ in this report.

109

The climate response to emissions is investigated with climate models, paleoclimatic insights and other lines of evidence. The assessment outcomes are used to categorise

thousands of scenarios via simple physically-based climate models (emulators). {WGI TS.1.2.2}

Section 2

Section 1

Section 2

Global Warming Levels (GWLs)

For many climate and risk variables, the geographical patterns of changes in climatic impact-drivers

110

and climate impacts for a level of global

warming

111

are common to all scenarios considered and independent of timing when that level is reached. This motivates the use of GWLs as a

dimension of integration. {WGI Box SPM.1.4, WGI TS.1.3.2; WGII Box SPM.1} (Figure 3.1, Figure 3.2)

Risks

Dynamic interactions between climate-related hazards, exposure and vulnerability of the affected human society, species, or ecosystems result

in risks arising from climate change. AR6 assesses key risks across sectors and regions as well as providing an updated assessment of the

Reasons for Concern (RFCs) – ﬁve globally aggregated categories of risk that evaluate risk accrual with increasing global surface temperature.

Risks can also arise from climate change mitigation or adaptation responses when the response does not achieve its intended objective, or when

it results in adverse effects for other societal objectives. {WGII SPM A, WGII Figure SPM.3, WGII Box TS.1, WGII Figure TS.4; SR1.5 Figure SPM.2;

SROCC Errata Figure SPM.3; SRCCL Figure SPM.2} (3.1.2, Cross-Section Box.2 Figure 1, Figure 3.3)

110

See Annex I: Glossary

111

See Annex I: Glossary. Here, global warming is the 20-year average global surface temperature relative to 1850–1900. The assessed time of when a certain global warming level

is reached under a particular scenario is deﬁned here as the mid-point of the ﬁrst 20-year running average period during which the assessed average global surface temperature

change exceeds the level of global warming. {WGI SPM footnote 26, Cross-Section Box TS.1}

Current Status and Trends

Section 2

which drivesthat changeinﬂuence

Emissions

a) AR6 integrated assessment framework on future climate, impacts and mitigation

Climate Impacts / Risks

Mitigation Policy Adaptation Policy

Socio-economic changes

°C

b) Scenarios and pathways across AR6 Working Group reports c) Determinants of risk

Temperature for SSP-based scenarios over the

century and C1-C8 at 2100

Risks

can be

represented as

“burning embers”

C1-C8 in 2100

increasing risk

2050

2100

100

2050

2100

GtCO

/yr

SSP1-1.9

SSP1-2.6

SSP2-4.5

SSP3-7.0

SSP5-8.5

SSP1-1.9

SSP1-2.6

SSP2-4.5

SSP3-7.0

SSP5-8.5

RFC1

Unique and

threatened systems

color shading shows

C1-C8 category

color shading shows

range for SSP3-7.0

and SSP1-2.6

Category

(2)

[# pathways]

[97]

C1a

[50]

C1b

[47]

[133]

[311]

C3a

[204]

C3b

[97]

[159]

C5 C6

[97]

Table 3.1: Key characteristics of the modelled global emissions pathways. Summary of projected CO

and GHG emissions, projected net zero timings and the resulting global

warming outcomes. Pathways are categorised (columns), according to their likelihood of limiting warming to different peak warming levels (if peak temperature occurs before 2100)

and 2100 warming levels. Values shown are for the median [p50] and 5–95th percentiles [p5–p95], noting that not all pathways achieve net zero CO

or GHGs. {WGIII Table SPM.2}

1 Detailed explanations on the Table are provided in WGIII Box SPM.1 and WGIII Table SPM.2. The relationship between the temperature categories and SSP/RCPs is discussed

in Cross-Section Box.2. Values in the table refer to the 50th and [5–95th] percentile values across the pathways falling within a given category as deﬁned in WGIII Box SPM.1.

The three dots (…) sign denotes that the value cannot be given (as the value is after 2100 or, for net zero, net zero is not reached). Based on the assessment of climate emulators

in AR6 WG I (Chapter 7, Box 7.1), two climate emulators were used for the probabilistic assessment of the resulting warming of the pathways. For the ‘Temperature Change’

and ‘Likelihood’ columns, the non-bracketed values represent the 50th percentile across the pathways in that category and the median [50th percentile] across the warming

estimates of the probabilistic MAGICC climate model emulator. For the bracketed ranges in the “likelihood” column, the median warming for every pathway in that category

is calculated for each of the two climate model emulators (MAGICC and FaIR). These ranges cover both the uncertainty of the emissions pathways as well as the climate

emulators’ uncertainty. All global warming levels are relative to 1850-1900.

2 C3 pathways are sub-categorised according to the timing of policy action to match the emissions pathways in WGIII Figure SPM.4.

3 Global emission reductions in mitigation pathways are reported on a pathway-by-pathway basis relative to harmonised modelled global emissions in 2019 rather than

Long-Term Climate and Development Futures

Section 3

3.3.2 Net Zero Emissions: Timing and Implications

From a physical science perspective, limiting human-caused

global warming to a speciﬁc level requires limiting cumulative

emissions, reaching net zero or net negative CO

emissions,

along with strong reductions of other GHG emissions

(see Cross-Section Box.1). Global modelled pathways that reach

and sustain net zero GHG emissions are projected to result in

a gradual decline in surface temperature (high conﬁdence).

Reaching net zero GHG emissions primarily requires deep reductions in

, methane, and other GHG emissions, and implies net negative

emissions.

134

Carbon dioxide removal (CDR) will be necessary to

achieve net negative CO

emissions

135

. Achieving global net zero

emissions, with remaining anthropogenic CO

emissions balanced by

durably stored CO

from anthropogenic removal, is a requirement to

stabilise CO

-induced global surface temperature increase (see 3.3.3)

(high conﬁdence). This is different from achieving net zero GHG

emissions, where metric-weighted anthropogenic GHG emissions (see

Cross-Section Box.1) equal CO

removal (high conﬁdence). Emissions

pathways that reach and sustain net zero GHG emissions deﬁned by the

100-year global warming potential imply net negative CO

emissions

and are projected to result in a gradual decline in surface temperature

after an earlier peak (high conﬁdence). While reaching net zero CO

or net

zero GHG emissions requires deep and rapid reductions in gross

emissions, the deployment of CDR to counterbalance hard-

to-abate residual emissions (e.g., some emissions from agriculture,

aviation, shipping, and industrial processes) is unavoidable (high

conﬁdence). {WGI SPM D.1, WGI SPM D.1.1, WGI SPM D.1.8; WGIII SPM C.2,

WGIII SPM C.3, WGIII SPM C.11, WGIII Box TS.6; SR1.5 SPM A.2.2}

In modelled pathways, the timing of net zero CO

emissions,

followed by net zero GHG emissions, depends on several

variables, including the desired climate outcome, the mitigation

strategy and the gases covered (high conﬁdence). Global net zero

emissions are reached in the early 2050s in pathways that limit

warming to 1.5°C (>50%) with no or limited overshoot, and around

the early 2070s in pathways that limit warming to 2°C (>67%). While

non-CO

GHG emissions are strongly reduced in all pathways that limit

warming to 2°C (>67%) or lower, residual emissions of CH

and N

and F-gases of about 8 [5–11] GtCO

-eq yr

-1

remain at the time of

134

Net zero GHG emissions deﬁned by the 100-year global warming potential. See footnote 70.

135

See Section 3.3.3 and 3.4.1.

net zero GHG, counterbalanced by net negative CO

emissions.

As a result, net zero CO

would be reached before net zero GHGs

(high conﬁdence). {WGIII SPM C.2, WGIII SPM C.2.3, WGIII SPM C.2.4,

WGIII Table SPM.2, WGIII 3.3} (Figure 3.6)

the global emissions reported in WGIII SPM Section B and WGIII Chapter 2; this ensures internal consistency in assumptions about emission sources and activities, as well as

consistency with temperature projections based on the physical climate science assessment by WGI (see WGIII SPM Footnote 49). Negative values (e.g., in C5, C6) represent

an increase in emissions. The modelled GHG emissions in 2019 are 55 [53–58] GtCO

-eq, thus within the uncertainty ranges of estimates for 2019 emissions [53-66] GtCO

-eq

(see 2.1.1).

4 Emissions milestones are provided for 5-year intervals in order to be consistent with the underlying 5-year time-step data of the modelled pathways. Ranges in square

brackets underneath refer to the range across the pathways, comprising the lower bound of the 5th percentile 5-year interval and the upper bound of the 95th percentile

5-year interval. Numbers in round brackets signify the fraction of pathways that reach speciﬁc milestones over the 21st century. Percentiles reported across all pathways in

that category include those that do not reach net zero before 2100.

5 For cases where models do not report all GHGs, missing GHG species are inﬁlled and aggregated into a Kyoto basket of GHG emissions in CO

-eq deﬁned by the 100-year

global warming potential. For each pathway, reporting of CO

, CH

, and N

O emissions was the minimum required for the assessment of the climate response and the assignment

to a climate category. Emissions pathways without climate assessment are not included in the ranges presented here. See WGIII Annex III.II.5.

6 Cumulative emissions are calculated from the start of 2020 to the time of net zero and 2100, respectively. They are based on harmonised net CO

emissions, ensuring

consistency with the WG I assessment of the remaining carbon budget. {WGIII Box 3.4, WGIII SPM Footnote 50}

Section 3

Section 1

Section 3

2000

2020

2040

2060

2080

2100

2000

2020

2040

2060

2080

2100

2000

2020

2040

2060

2080

2100

2000

2020

2040

2060

2080

2100

Gigatons of CO

equivalent per year (GtCO

-eq/yr)

GHG

a) While keeping warming to 1.5°C

(>50%) with no or limited overshoot

b) While keeping warming to 2°C (>67%)

c) Timing for net zero

net zero net zero

Historical Historical

Policies in place in 2020 Policies in place in 2020

GHGs reach net zero

later than CO

not all

scenarios

reach net

zero GHG

by 2100

Global modelled pathways that limit warming to 1.5°C (>50%) with

no or limited overshoot reach net zero CO

emissions around 2050

Total greenhouse gases (GHG) reach net zero later

Figure 3.6: Total GHG, CO

and CH

emissions and timing of reaching net zero in different mitigation pathways. Top row: GHG, CO

and CH

emissions over time (in

GtCO

eq) with historical emissions, projected emissions in line with policies implemented until the end of 2020 (grey), and pathways consistent with temperature goals in colour

(blue, purple, and brown, respectively). Panel (a) (left) shows pathways that limit warming to 1.5°C (>50%) with no or limited overshoot (C1) and Panel (b) (right) shows

pathways that limit warming to 2°C (>67%) (C3). Bottom row: Panel (c) shows median (vertical line), likely (bar) and very likely (thin lines) timing of reaching net zero GHG

and CO

emissions for global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot (C1) (left) or 2°C (>67%) (C3) (right). {WGIII Figure SPM.5}

3.3.3 Sectoral Contributions to Mitigation

All global modelled pathways that limit warming to 2°C (>67%) or

lower by 2100 involve rapid and deep and in most cases immediate

GHG emissions reductions in all sectors (see also 4.1, 4.5). Reductions

in GHG emissions in industry, transport, buildings, and urban areas

can be achieved through a combination of energy efﬁciency and

conservation and a transition to low-GHG technologies and energy

carriers (see also 4.5, Figure 4.4). Socio-cultural options and behavioural

change can reduce global GHG emissions of end-use sectors, with most

of the potential in developed countries, if combined with improved

136

CCS is an option to reduce emissions from large-scale fossil-based energy and industry sources provided geological storage is available. When CO

is captured directly from the

atmosphere (DACCS), or from biomass (BECCS), CCS provides the storage component of these CDR methods. CO

capture and subsurface injection is a mature technology for

gas processing and enhanced oil recovery. In contrast to the oil and gas sector, CCS is less mature in the power sector, as well as in cement and chemicals production, where it

is a critical mitigation option. The technical geological storage capacity is estimated to be on the order of 1000 GtCO

, which is more than the CO

storage requirements through

2100 to limit global warming to 1.5°C, although the regional availability of geological storage could be a limiting factor. If the geological storage site is appropriately selected and

managed, it is estimated that the CO

can be permanently isolated from the atmosphere. Implementation of CCS currently faces technological, economic, institutional, ecological

environmental and socio-cultural barriers. Currently, global rates of CCS deployment are far below those in modelled pathways limiting global warming to 1.5°C to 2°C. Enabling

conditions such as policy instruments, greater public support and technological innovation could reduce these barriers. (high conﬁdence) {WGIII SPM C.4.6}

infrastructure design and access. (high conﬁdence) {WGIII SPM C.3,

WGIII SPM C.5, WGIII SPM C.6, WGIII SPM C.7.3, WGIII SPM C.8,

WGIII SPM C.10.2}

Global modelled mitigation pathways reaching net zero CO

and

GHG emissions include transitioning from fossil fuels without

carbon capture and storage (CCS) to very low- or zero-carbon

energy sources, such as renewables or fossil fuels with CCS,

demand-side measures and improving efﬁciency, reducing

non-CO

GHG emissions, and CDR

136

. In global modelled pathways

that limit warming to 2°C or below, almost all electricity is supplied

Long-Term Climate and Development Futures

Section 3

from zero or low-carbon sources in 2050, such as renewables or

fossil fuels with CO

capture and storage, combined with increased

electriﬁcation of energy demand. Such pathways meet energy service

demand with relatively low energy use, through e.g., enhanced energy

efﬁciency and behavioural changes and increased electriﬁcation of

energy end use. Modelled global pathways limiting global warming to

1.5°C (>50%) with no or limited overshoot generally implement such

changes faster than pathways limiting global warming to 2°C (>67%).

(high conﬁdence) {WGIII SPM C.3, WGIII SPM C.3.2, WGIII SPM C.4,

WGIII TS.4.2; SR1.5 SPM C.2.2}

AFOLU mitigation options, when sustainably implemented, can

deliver large-scale GHG emission reductions and enhanced CO

removal; however, barriers to implementation and trade-offs

may result from the impacts of climate change, competing

demands on land, conﬂicts with food security and livelihoods,

the complexity of land ownership and management systems,

and cultural aspects (see 3.4.1). All assessed modelled pathways

that limit warming to 2°C (>67%) or lower by 2100 include land-based

mitigation and land-use change, with most including different

combinations of reforestation, afforestation, reduced deforestation, and

bioenergy. However, accumulated carbon in vegetation and soils is at

risk from future loss (or sink reversal) triggered by climate change and

disturbances such as ﬂood, drought, ﬁre, or pest outbreaks, or future

poor management. (high conﬁdence) {WGI SPM B.4.3; WGII SPM B.2.3,

WGII SPM B.5.4; WGIII SPM C.9, WGIII SPM C.11.3, WGIII SPM D.2.3,

WGIII TS.4.2, 3.4; SR1.5 SPM C.2.5; SRCCL SPM B.1.4, SRCCL SPM B.3,

SRCCL SPM B.7}

In addition to deep, rapid, and sustained emission reductions,

CDR can fulﬁl three complementary roles: lowering net CO

or net GHG emissions in the near term; counterbalancing

‘hard-to-abate’ residual emissions (e.g., some emissions from

agriculture, aviation, shipping, industrial processes) to help reach

net zero CO

or GHG emissions, and achieving net negative

or GHG emissions if deployed at levels exceeding annual

residual emissions (high conﬁdence). CDR methods vary in terms

of their maturity, removal process, time scale of carbon storage, storage

medium, mitigation potential, cost, co-beneﬁts, impacts and risks, and

governance requirements (high conﬁdence). Speciﬁcally, maturity

ranges from lower maturity (e.g., ocean alkalinisation) to higher

maturity (e.g., reforestation); removal and storage potential ranges

from lower potential (<1 Gt CO

-1

, e.g., blue carbon management)

to higher potential (>3 Gt CO

-1

, e.g., agroforestry); costs range from

lower cost (e.g., –45 to 100 USD tCO

-1

for soil carbon sequestration)

to higher cost (e.g., 100 to 300 USD tCO

-1

for direct air carbon dioxide

capture and storage) (medium conﬁdence). Estimated storage timescales

vary from decades to centuries for methods that store carbon in

vegetation and through soil carbon management, to ten thousand years

or more for methods that store carbon in geological formations (high

conﬁdence). Afforestation, reforestation, improved forest management,

agroforestry and soil carbon sequestration are currently the only widely

practiced CDR methods (high conﬁdence). Methods and levels of CDR

deployment in global modelled mitigation pathways vary depending on

assumptions about costs, availability and constraints (high conﬁdence).

{WGIII SPM C.3.5, WGIII SPM C.11.1, WGIII SPM C.11.4}

137

Limited overshoot refers to exceeding 1.5°C global warming by up to about 0.1°C, high overshoot by 0.1°C to 0.3°C, in both cases for up to several decades. {WGIII Box SPM.1}

3.3.4 Overshoot Pathways: Increased Risks and Other

Implications

Exceeding a speciﬁc remaining carbon budget results in

higher global warming. Achieving and sustaining net negative

global CO

emissions could reverse the resulting temperature

exceedance (high conﬁdence). Continued reductions in emissions of

short-lived climate forcers, particularly methane, after peak temperature

has been reached, would also further reduce warming (high conﬁdence).

Only a small number of the most ambitious global modelled pathways

limit global warming to 1.5°C (>50%) without overshoot. {WGI SPM D.1.1,

WGI SPM D.1.6, WGI SPM D.1.7; WGIII TS.4.2}

Overshoot of a warming level results in more adverse impacts, some

irreversible, and additional risks for human and natural systems

compared to staying below that warming level, with risks growing

with the magnitude and duration of overshoot (high conﬁdence).

Compared to pathways without overshoot, societies and ecosystems

would be exposed to greater and more widespread changes in climatic

impact-drivers, such as extreme heat and extreme precipitation, with

increasing risks to infrastructure, low-lying coastal settlements, and

associated livelihoods (high conﬁdence). Overshooting 1.5°C will result

in irreversible adverse impacts on certain ecosystems with low resilience,

such as polar, mountain, and coastal ecosystems, impacted by ice-sheet

melt, glacier melt, or by accelerating and higher committed sea level

rise (high conﬁdence). Overshoot increases the risks of severe impacts,

such as increased wildﬁres, mass mortality of trees, drying of peatlands,

thawing of permafrost and weakening natural land carbon sinks; such

impacts could increase releases of GHGs making temperature reversal

more challenging (medium conﬁdence). {WGI SPM C.2, WGI SPM C.2.1,

WGI SPM C.2.3; WGII SPM B.6, WGII SPM B.6.1, WGII SPM B.6.2; SR1.5 3.6}

The larger the overshoot, the more net negative CO

emissions needed

to return to a given warming level (high conﬁdence). Reducing global

temperature by removing CO

would require net negative emissions of

220 GtCO

(best estimate, with a likely range of 160 to 370 GtCO

)

for every tenth of a degree (medium conﬁdence). Modelled pathways

that limit warming to 1.5°C (>50%) with no or limited overshoot reach

median values of cumulative net negative emissions of 220 GtCO

by 2100, pathways that return warming to 1.5°C (>50%) after high

overshoot reach median values of 360 GtCO

(high conﬁdence).

137

More rapid reduction in CO

and non-CO

emissions, particularly

methane, limits peak warming levels and reduces the requirement

for net negative CO

emissions and CDR, thereby reducing feasibility

and sustainability concerns, and social and environmental risks (high

confidence). {WGI SPM D.1.1; WGIII SPM B.6.4, WGIII SPM C.2,

WGIII SPM C.2.2, WGIII Table SPM.2}

Section 3

Section 1

Section 3

3.4.1 Synergies and trade-offs, costs and beneﬁts

Mitigation and adaptation options can lead to synergies and

trade-offs with other aspects of sustainable development

(see also Section 4.6, Figure 4.4). Synergies and trade-offs depend

on the pace and magnitude of changes and the development context

including inequalities, with consideration of climate justice. The

potential or effectiveness of some adaptation and mitigation options

decreases as climate change intensiﬁes (see also Sections 3.2, 3.3.3,

4.5). (high conﬁdence) {WGII SPM C.2, WGII Figure SPM.4b; WGIII SPM D.1,

WGIII SPM D.1.2, WGIII TS.5.1, WGIII Figure SPM.8; SR1.5 SPM D.3,

SR1.5 SPM D.4; SRCCL SPM B.2, SRCCL SPM B.3, SRCCL SPM D.3.2,

SRCCL Figure SPM.3}

In the energy sector, transitions to low-emission systems will have

multiple co-beneﬁts, including improvements in air quality and health.

There are potential synergies between sustainable development and,

for instance, energy efﬁciency and renewable energy. (high conﬁdence)

{WGIII SPM C.4.2, WGIII SPM D.1.3}

For agriculture, land, and food systems, many land management

options and demand-side response options (e.g., dietary choices,

reduced post-harvest losses, reduced food waste) can contribute to

eradicating poverty and eliminating hunger while promoting good health

and well-being, clean water and sanitation, and life on land (medium

confidence). In contrast, certain adaptation options that promote

intensification of production, such as irrigation, may have negative

effects on sustainability (e.g., for biodiversity, ecosystem services,

groundwater depletion, and water quality) (high confidence). {WGII

TS.D.5.5; WGIII SPM D.10; SRCCL SPM B.2.3}

Reforestation, improved forest management, soil carbon sequestration,

peatland restoration and coastal blue carbon management are

examples of CDR methods that can enhance biodiversity and ecosystem

functions, employment and local livelihoods, depending on context

139

However, afforestation or production of biomass crops for bioenergy

with carbon dioxide capture and storage or biochar can have adverse

socio-economic and environmental impacts, including on biodiversity,

food and water security, local livelihoods and the rights of Indigenous

Peoples, especially if implemented at large scales and where land

tenure is insecure. (high conﬁdence) {WGII SPM B.5.4, WGII SPM C.2.4;

WGIII SPM C.11.2; SR1.5 SPM C.3.4, SR1.5 SPM C.3.5; SRCCL SPM B.3,

SRCCL SPM B.7.3, SRCCL Figure SPM.3}

139

The impacts, risks, and co-beneﬁts of CDR deployment for ecosystems, biodiversity and people will be highly variable depending on the method, site-speciﬁc context,

implementation and scale (high conﬁdence). {WGIII SPM C.11.2}

140

The evidence is too limited to make a similar robust conclusion for limiting warming to 1.5°C. {WGIII SPM footnote 68}

Modelled pathways that assume using resources more efﬁciently or shift

global development towards sustainability include fewer challenges, such

as dependence on CDR and pressure on land and biodiversity, and have

the most pronounced synergies with respect to sustainable development

(high conﬁdence). {WGIII SPM C.3.6; SR1.5 SPM D.4.2}

Strengthening climate change mitigation action entails more

rapid transitions and higher up-front investments, but brings

beneﬁts from avoiding damages from climate change and

reduced adaptation costs. The aggregate effects of climate change

mitigation on global GDP (excluding damages from climate change and

adaptation costs) are small compared to global projected GDP growth.

Projected estimates of global aggregate net economic damages and

the costs of adaptation generally increase with global warming level.

(high conﬁdence) {WGII SPM B.4.6, WGII TS.C.10; WGIII SPM C.12.2,

WGIII SPM C.12.3}

Cost-beneﬁt analysis remains limited in its ability to represent all

damages from climate change, including non-monetary damages,

or to capture the heterogeneous nature of damages and the risk of

catastrophic damages (high conﬁdence). Even without accounting for

these factors or for the co-beneﬁts of mitigation, the global beneﬁts

of limiting warming to 2°C exceed the cost of mitigation (medium

conﬁdence). This ﬁnding is robust against a wide range of assumptions

about social preferences on inequalities and discounting over time

(medium conﬁdence). Limiting global warming to 1.5°C instead of 2°C

would increase the costs of mitigation, but also increase the beneﬁts

in terms of reduced impacts and related risks (see 3.1.1, 3.1.2) and

reduced adaptation needs (high confidence)

140

. {WGII SPM B.4, WGII

SPM B.6; WGIII SPM C.12, WGIII SPM C.12.2, WGIII SPM C.12.3 WGIII Box TS.7;

SR1.5 SPM B.3, SR1.5 SPM B.5, SR1.5 SPM B.6}

Considering other sustainable development dimensions, such as the

potentially strong economic beneﬁts on human health from air quality

improvement, may enhance the estimated beneﬁts of mitigation

(medium conﬁdence). The economic effects of strengthened mitigation

action vary across regions and countries, depending notably on economic

structure, regional emissions reductions, policy design and level of

international cooperation (high conﬁdence). Ambitious mitigation

pathways imply large and sometimes disruptive changes in economic

structure, with implications for near-term actions (Section 4.2), equity

(Section 4.4), sustainability (Section 4.6), and ﬁnance (Section 4.8)

(high conﬁdence). {WGIII SPM C.12.2, WGIII SPM D.3.2, WGIII TS.4.2}

3.4 Long-Term Interactions Between Adaptation, Mitigation and Sustainable Development

Mitigation and adaptation can lead to synergies and trade-offs with sustainable development (high conﬁdence).

Accelerated and equitable mitigation and adaptation bring beneﬁts from avoiding damages from climate

change and are critical to achieving sustainable development (high conﬁdence). Climate resilient development

138

pathways are progressively constrained by every increment of further warming (very high conﬁdence). There is a

rapidly closing window of opportunity to secure a liveable and sustainable future for all (very high conﬁdence).

138

See Annex I: Glossary.

139

The impacts, risks, and co-beneﬁts of CDR deployment for ecosystems, biodiversity and people will be highly variable depending on the method, site-speciﬁc context,

implementation and scale (high conﬁdence). {WGIII SPM C.11.2}

140

The evidence is too limited to make a similar robust conclusion for limiting warming to 1.5°C. {WGIII SPM footnote 68}

Long-Term Climate and Development Futures

Section 3

3.4.2 Advancing Integrated Climate Action for Sustainable

Development

An inclusive, equitable approach to integrating adaptation, mitigation

and development can advance sustainable development in the long

term (high conﬁdence). Integrated responses can harness synergies for

sustainable development and reduce trade-offs (high conﬁdence). Shifting

development pathways towards sustainability and advancing climate

resilient development is enabled when governments, civil society

and the private sector make development choices that prioritise risk

reduction, equity and justice, and when decision-making processes,

ﬁnance and actions are integrated across governance levels, sectors

and timeframes (very high conﬁdence) (see also Figure 4.2). Inclusive

processes involving local knowledge and Indigenous Knowledge

increase these prospects (high conﬁdence). However, opportunities

for action differ substantially among and within regions, driven by

historical and ongoing patterns of development (very high conﬁdence).

Accelerated ﬁnancial support for developing countries is critical to enhance

mitigation and adaptation action (high conﬁdence). {WGII SPM C.5.4,

WGII SPM D.1, WGII SPM D.1.1, WGII SPM D.1.2, WGII SPM D.2,

WGII SPM D.3, WGII SPM D.5, WGII SPM D.5.1, WGII SPM D.5.2;

WGIII SPM D.1, WGIII SPM D.2, WGIII SPM D.2.4, WGIII SPM E.2.2,

WGIII SPM E.2.3, WGIII SPM E.5.3, WGIII Cross-Chapter Box 5}

Policies that shift development pathways towards sustainability

can broaden the portfolio of available mitigation and adaptation

responses (medium conﬁdence). Combining mitigation with action

to shift development pathways, such as broader sectoral policies,

approaches that induce lifestyle or behaviour changes, ﬁnancial

regulation, or macroeconomic policies can overcome barriers and

open up a broader range of mitigation options (high conﬁdence).

Integrated, inclusive planning and investment in everyday decision-

making about urban infrastructure can signiﬁcantly increase the

adaptive capacity of urban and rural settlements. Coastal cities and

settlements play an important role in advancing climate resilient

development due to the high number of people living in the Low

Elevation Coastal Zone, the escalating and climate compounded risk

that they face, and their vital role in national economies and beyond

(high conﬁdence). {WGII SPM.D.3, WGII SPM D.3.3; WGIII SPM E.2,

WGIII SPM E.2.2; SR1.5 SPM D.6}

Observed adverse impacts and related losses and damages,

projected risks, trends in vulnerability, and adaptation limits

demonstrate that transformation for sustainability and climate

resilient development action is more urgent than previously

assessed (very high conﬁdence). Climate resilient development

integrates adaptation and GHG mitigation to advance

sustainable development for all. Climate resilient development

pathways have been constrained by past development, emissions and

climate change and are progressively constrained by every increment

of warming, in particular beyond 1.5°C (very high conﬁdence).

Climate resilient development will not be possible in some regions

and sub-regions if global warming exceeds 2°C (medium conﬁdence).

Safeguarding biodiversity and ecosystems is fundamental to climate

resilient development, but biodiversity and ecosystem services have

limited capacity to adapt to increasing global warming levels, making

climate resilient development progressively harder to achieve beyond

1.5°C warming (very high conﬁdence). {WGII SPM D.1, WGII SPM D.1.1,

WGII SPM D.4, WGII SPM D.4.3, WGII SPM D.5.1; WGIII SPM D.1.1}

The cumulative scientiﬁc evidence is unequivocal: climate change

is a threat to human well-being and planetary health (very

high conﬁdence). Any further delay in concerted anticipatory

global action on adaptation and mitigation will miss a brief and

rapidly closing window of opportunity to secure a liveable and

sustainable future for all (very high conﬁdence). Opportunities for

near-term action are assessed in the following section. {WGII SPM D.5.3;

WGIII SPM D.1.1}

Section 4

Near-Term Responses

in a Changing Climate

Section 4

Section 1

Section 4

Section 4 : Near-Term Responses in a Changing Climate

4.1 The Timing and Urgency of Climate Action

The magnitude and rate of climate change and associated risks

depend strongly on near-term mitigation and adaptation actions

(very high conﬁdence). Global warming is more likely than not to reach

1.5°C between 2021 and 2040 even under the very low GHG emission

scenarios (SSP1-1.9), and likely or very likely to exceed 1.5°C under

higher emissions scenarios

141

. Many adaptation options have medium

or high feasibility up to 1.5°C (medium to high conﬁdence, depending

on option), but hard limits to adaptation have already been reached

in some ecosystems and the effectiveness of adaptation to reduce

climate risk will decrease with increasing warming (high conﬁdence).

Societal choices and actions implemented in this decade determine the

extent to which medium- and long-term pathways will deliver higher or

lower climate resilient development (high conﬁdence). Climate resilient

development prospects are increasingly limited if current greenhouse

gas emissions do not rapidly decline, especially if 1.5°C global warming

is exceeded in the near term (high conﬁdence). Without urgent, effective

and equitable adaptation and mitigation actions, climate change

increasingly threatens the health and livelihoods of people around

the globe, ecosystem health, and biodiversity, with severe adverse

consequences for current and future generations (high conﬁdence).

{WGI SPM B.1.3, WGI SPM B.5.1, WGI SPM B.5.2; WGII SPM A, WGII

SPM B.4, WGII SPM C.2, WGII SPM C.3.3, WGII Figure SPM.4, WGII SPM

D.1, WGII SPM D.5, WGIII SPM D.1.1 SR1.5 SPM D.2.2}. (Cross-Section

Box.2, Figure 2.1, Figure 2.3)

141

In the near term (2021–2040), the 1.5°C global warming level is very likely to be exceeded under the very high GHG emissions scenario (SSP5-8.5), likely to be exceeded under

the intermediate and high GHG emissions scenarios (SSP2-4.5, SSP3-7.0), more likely than not to be exceeded under the low GHG emissions scenario (SSP1-2.6) and more likely

than not to be reached under the very low GHG emissions scenario (SSP1-1.9). The best estimates [and very likely ranges] of global warming for the different scenarios in the

near term are: 1.5 [1.2 to 1.7]°C (SSP1-1.9); 1.5 [1.2 to 1.8]°C (SSP1-2.6); 1.5 [1.2 to 1.8]°C (SSP2-4.5); 1.5 [1.2 to 1.8]°C (SSP3-7.0); and 1.6[1.3 to 1.9]°C (SSP5-8.5).

{WGI SPM B.1.3, WGI Table SPM.1} (Cross-Section Box.2)

142

Values in parentheses indicate the likelihood of limiting warming to the level speciﬁed (see Cross-Section Box.2).

143

Median and very likely range [5th to 95th percentile]. {WGIII SPM footnote 30}

144

These numbers for CO

are 48 [36 to 69]% in 2030, 65 [50 to 96] % in 2035, 80 [61 to109] % in 2040 and 99 [79 to 119]% in 2050.

145

These numbers for CO

are 22 [1 to 44]% in 2030, 37 [21 to 59] % in 2035, 51 [36 to 70] % in 2040 and 73 [55 to 90]% in 2050.

146

In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce the amount of GHG emitted throughout the life

cycle; for example, capturing 90% or more CO

from power plants, or 50 to 80% of fugitive methane emissions from energy supply. {WGIII SPM footnote 54}

In modelled pathways that limit warming to 1.5°C (>50%) with

no or limited overshoot and in those that limit warming to

2°C (>67%), assuming immediate actions, global GHG emissions

are projected to peak in the early 2020s followed by rapid and

deep GHG emissions reductions (high conﬁdence)

142

. In pathways

that limit warming to 1.5°C (>50%) with no or limited overshoot, net

global GHG emissions are projected to fall by 43 [34 to 60]%

143

below

2019 levels by 2030, 60 [49 to 77]% by 2035, 69 [58 to 90]% by 2040

and 84 [73 to 98]% by 2050 (high conﬁdence) (Section 2.3.1, Table 2.2,

Figure 2.5, Table 3.1)

144

. Global modelled pathways that limit warming

to 2°C (>67%) have reductions in GHG emissions below 2019 levels

of 21 [1 to 42]% by 2030, 35 [22 to 55] % by 2035, 46 [34 to 63]

% by 2040 and 64 [53 to 77]% by 2050

145

(high conﬁdence). Global

GHG emissions associated with NDCs announced prior to COP26 would

make it likely that warming would exceed 1.5°C (high conﬁdence)

and limiting warming to 2°C (>67%) would then imply a rapid

acceleration of emission reductions during 2030–2050, around

70% faster than in pathways where immediate action is taken to

limit warming to 2°C (>67%) (medium conﬁdence) (Section 2.3.1)

Continued investments in unabated high-emitting infrastructure

146

and

limited development and deployment of low-emitting alternatives

prior to 2030 would act as barriers to this acceleration and increase

feasibility risks (high confidence). {WGIII SPM B.6.3, WGIII 3.5.2,

WGIII SPM B.6, WGIII SPM B.6., WGIII SPM C.1, WGIII SPM C1.1,

WGIII Table SPM.2} (Cross-Section Box.2)

Deep, rapid, and sustained mitigation and accelerated implementation of adaptation reduces the risks of climate

change for humans and ecosystems. In modelled pathways that limit warming to 1.5°C (>50%) with no or limited

overshoot and in those that limit warming to 2°C (>67%) and assume immediate action, global GHG emissions

are projected to peak in the early 2020s followed by rapid and deep reductions. As adaptation options often have

long implementation times, accelerated implementation of adaptation, particularly in this decade, is important

to close adaptation gaps. (high conﬁdence)

Near-Term Responses in a Changing Climate

Section 4

All global modelled pathways that limit warming to 2°C (>67%)

or lower by 2100 involve reductions in both net CO

emissions

and non-CO

emissions (see Figure 3.6) (high confidence).

For example, in pathways that limit warming to 1.5°C (>50%)

with no or limited overshoot, global CH

(methane) emissions are

reduced by 34 [21 to 57]% below 2019 levels by 2030 and by

44 [31 to 63]% in 2040 (high confidence). Global CH

emissions

are reduced by 24 [9 to 53]% below 2019 levels by 2030 and by

37 [20 to 60]% in 2040 in modelled pathways that limit warming to

2°C with action starting in 2020 (>67%) (high conﬁdence). {WGIII SPM

C1.2, WGIII Table SPM.2, WGIII 3.3; SR1.5 SPM C.1, SR1.5 SPM C.1.2}

(Cross-Section Box.2)

All global modelled pathways that limit warming to 2°C (>67%)

or lower by 2100 involve GHG emission reductions in all sectors

(high conﬁdence). The contributions of different sectors vary across

modelled mitigation pathways. In most global modelled mitigation

pathways, emissions from land-use, land-use change and forestry, via

reforestation and reduced deforestation, and from the energy supply

sector reach net zero CO

emissions earlier than the buildings, industry

and transport sectors (Figure 4.1). Strategies can rely on combinations

of different options (Figure 4.1, Section 4.5), but doing less in one

sector needs to be compensated by further reductions in other sectors if

warming is to be limited. (high conﬁdence) {WGIII SPM C.3, WGIII SPM

C.3.1, WGIII SPM 3.2, WGIII SPM C.3.3} (Cross-Section Box.2)

Without rapid, deep and sustained mitigation and accelerated

adaptation actions, losses and damages will continue to

increase, including projected adverse impacts in Africa, LDCs,

SIDS, Central and South America

147

, Asia and the Arctic, and will

disproportionately affect the most vulnerable populations (high

conﬁdence). {WGII SPM C.3.5, WGII SPM B.2.4, WGII 12.2, WGII 10.

Box 10.6, WGII TS D.7.5, WGII Cross-Chapter Box 6 ES, WGII Global

to Regional Atlas Annex A1.15, WGII Global to Regional Atlas Annex

A1.27; SR1.5 SPM B.5.3, SR 1.5 SPM B.5.7; SRCCL A.5.6} (Figure 3.2;

Figure 3.3)

147

The southern part of Mexico is included in the climatic subregion South Central America (SCA) for WGI. Mexico is assessed as part of North America for WGII. The climate change

literature for the SCA region occasionally includes Mexico, and in those cases WGII assessment makes reference to Latin America. Mexico is considered part of Latin America and

the Caribbean for WGIII. {WGII 12.1.1, WGIII AII.1.1}

Section 4

Section 1

Section 4

a) Sectoral emissions in pathways that limit warming to 1.5°C

b) Greenhouse gas emissions by sector at

the time of net zero CO

, compared to 2019

The transition towards net zero CO

will

have different pace across different sectors

emissions from the electricity/fossil fuel industries sector and

land-use change generally reach net zero earlier than other sectors

includes halting

deforestation

Percentage reduction in CO

emissions relative to 2015

includes

decarbonised

electricity supply

Transport, industry

and buildings

Energy supply

(including electricity)

Non-CO

emissions

Land-use

change

Key

Pathways consistent with limiting

warming to 1.5°C or 2°C by 2100

IMP-GS

IMP-Neg*

IMP-LD

IMP-SP

IMP-Ren

Gradual strengthening

High reliance on net negative emissions

High reliance on efﬁcient resource use

Focus on sustainable development

Focus on renewables

Transport, industry and buildings

Non-CO

emissions

Land-use change and forestry

Energy supply (including electricity)

*High overshoot

pathways to 2°C also reach net zero CO

GHG emissions

(GtCO

-eq/yr)

Sources

Sinks

2020

2030

2040

2050

−125%

−100%

−75%

−25%

net zero

halfway

to net zero

pathways for

2°C reach net zero

somewhat later

−20

20

40

60

2019

comparison

IMP-Neg

IMP-GS

IMP-Ren

IMP-LD

IMP-SP

these are dierent

ways to achieve

net zero CO

Illustrative Mitigation

Pathways (IMPs)

net zero

Near-Term Responses in a Changing Climate

Section 4

4.2 Beneﬁts of Strengthening Near-Term Action

Figure 4.1: Sectoral emissions in pathways that limit warming to 1.5°C. Panel (a) shows sectoral CO

and non-CO

emissions in global modelled pathways that limit

warming to 1.5°C (>50%) with no or limited overshoot. The horizontal lines illustrate halving 2015 emissions (base year of the pathways) (dashed) and reaching net zero emissions

(solid line). The range shows the 5–95th percentile of the emissions across the pathways. The timing strongly differs by sector, with the CO

emissions from the electricity/fossil fuel

industries sector andland-use change generally reaching net zero earlier.Non-CO

emissions from agriculture are also substantially reduced compared to pathways without climate

policy but do not typically reach zero. Panel (b) Although all pathways include strongly reduced emissions, there are different pathways as indicated by the illustrative mitigation

pathways used in IPCC WGIII. The pathways emphasise routes consistent with limiting warming to 1.5°C with a high reliance on net negative emissions (IMP-Neg), high resource

efﬁciency (IMP-LD), a focus on sustainable development (IMP-SP) or renewables (IMP-Ren) and consistent with 2°C based on a less rapid introduction of mitigation measures followed

by a subsequent gradual strengthening (IMP-GS). Positive (solid ﬁlled bars) and negative emissions (hatched bars) for different illustrative mitigation pathways are compared to

GHG emissions from the year 2019. The category “energy supply (including electricity)” includes bioenergy with carbon capture and storage and direct air carbon capture and storage.

{WGIII Box TS.5, WGIII 3.3, WGIII 3.4, WGIII 6.6, WGIII 10.3, WGIII 11.3} (Cross-Section Box.2)

Accelerated implementation of adaptation will improve well-being by reducing losses and damages, especially

for vulnerable populations. Deep, rapid, and sustained mitigation actions would reduce future adaptation costs

and losses and damages, enhance sustainable development co-beneﬁts, avoid locking-in emission sources,

and reduce stranded assets and irreversible climate changes. These near-term actions involve higher up-front

investments and disruptive changes, which can be moderated by a range of enabling conditions and removal or

reduction of barriers to feasibility. (high conﬁdence)

Accelerated implementation of adaptation responses will bring

beneﬁts to human well-being (high conﬁdence) (Section 4.3). As

adaptation options often have long implementation times, long-term

planning and accelerated implementation, particularly in this decade, is

important to close adaptation gaps, recognising that constraints remain

for some regions. The beneﬁts to vulnerable populations would be high

(see Section 4.4). (high conﬁdence) {WGI SPM B.1, WGI SPM B.1.3, WGI

SPM B.2.2, WGI SPM B.3; WGII SPM C.1.1, WGII SPM C.1.2, WGII SPM

C.2, WGII SPM C.3.1, WGII Figure SPM.4b; SROCC SPM C.3.4, SROCC

Figure 3.4, SROCC Figure SPM.5}

Near-term actions that limit global warming to close to 1.5°C

would substantially reduce projected losses and damages related

to climate change in human systems and ecosystems, compared

to higher warming levels, but cannot eliminate them all (very

high conﬁdence). The magnitude and rate of climate change and

associated risks depend strongly on near-term mitigation and adaptation

actions, and projected adverse impacts and related losses and damages

escalate with every increment of global warming (very high conﬁdence).

Delayed mitigation action will further increase global warming which

will decrease the effectiveness of many adaptation options, including

Ecosystem-based Adaptation and many water-related options, as well

as increasing mitigation feasibility risks, such as for options based on

ecosystems (high conﬁdence). Comprehensive, effective, and innovative

responses integrating adaptation and mitigation can harness synergies

and reduce trade-offs between adaptation and mitigation, as well as in

meeting requirements for ﬁnancing (very high conﬁdence) (see Section

4.5, 4.6, 4.8 and 4.9). {WGII SPM B.3, WGII SPM B.4, WGII SPM B.6.2,

WGII SPM C.2, WGII SPM C.3, WGII SPM D.1, WGII SPM D.4.3, WGII SPM D.5,

WG II TS D.1.4, WG II TS.D.5, WGII TS D.7.5; WGIII SPM B.6.3,WGIII SPM B.6.4,

WGIII SPM C.9, WGIII SPM D.2, WGIII SPM E.13; SR1.5 SPM C.2.7,

SR1.5 D.1.3, SR1.5 D.5.2}

Mitigation actions will have other sustainable development

co-beneﬁts (high conﬁdence). Mitigation will improve air quality and

human health in the near term notably because many air pollutants are

148

In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce the amount of GHG emitted throughout the life

cycle; for example, capturing 90% or more CO

from power plants, or 50 to 80% of fugitive methane emissions from energy supply. {WGIII SPM footnote 54}

co-emitted by GHG emitting sectors and because methane emissions

leads to surface ozone formation (high conﬁdence). The beneﬁts from

air quality improvement include prevention of air pollution-related

premature deaths, chronic diseases and damages to ecosystems

and crops. The economic beneﬁts for human health from air quality

improvement arising from mitigation action can be of the same order

of magnitude as mitigation costs, and potentially even larger (medium

conﬁdence). As methane has a short lifetime but is a potent GHG,

strong, rapid and sustained reductions in methane emissions can limit

near-term warming and improve air quality by reducing global surface

ozone (high conﬁdence). {WGI SPM D.1.7, WGI SPM D.2.2, WGI 6.7,

WGI TS Box TS.7, WGI 6 Box 6.2, WGI Figure 6.3, WGI Figure 6.16,

WGI Figure 6.17; WGII TS.D.8.3, WGII Cross-Chapter Box HEALTH,

WGII 5 ES, WGII 7 ES; WGII 7.3.1.2; WGIII Figure SPM.8, WGIII SPM

C.2.3, WGIII SPM C.4.2, WGIII TS.4.2}

Challenges from delayed adaptation and mitigation actions

include the risk of cost escalation, lock-in of infrastructure,

stranded assets, and reduced feasibility and effectiveness

of adaptation and mitigation options (high conﬁdence). The

continued installation of unabated fossil fuel

148

infrastructure

will ‘lock-in’ GHG emissions (high conﬁdence). Limiting global

warming to 2°C or below will leave a substantial amount of fossil fuels

unburned and could strand considerable fossil fuel infrastructure

(high confidence), with globally discounted value projected to be

around USD 1 to 4 trillion from 2015 to 2050 (medium conﬁdence).

Early actions would limit the size of these stranded assets, whereas

delayed actions with continued investments in unabated high-emitting

infrastructure and limited development and deployment of low-emitting

alternatives prior to 2030 would raise future stranded assets to the

higher end of the range – thereby acting as barriers and increasing

political economy feasibility risks that may jeopardise efforts to limit

global warming. (high conﬁdence). {WGIII SPM B.6.3, WGIII SPM C.4,

WGIII Box TS.8}

Section 4

Section 1

Section 4

Scaling-up near-term climate actions (Section 4.1) will mobilise a

mix of low-cost and high-cost options. High-cost options, as in energy

and infrastructure, are needed to avoid future lock-ins, foster innovation

and initiate transformational changes (Figure 4.4). Climate resilient

development pathways in support of sustainable development for all are

shaped by equity, and social and climate justice (very high conﬁdence).

Embedding effective and equitable adaptation and mitigation in

development planning can reduce vulnerability, conserve and restore

ecosystems, and enable climate resilient development. This is especially

challenging in localities with persistent development gaps and limited

resources. (high conﬁdence) {WGII SPM C.5, WGII SPM D1; WGIII TS.5.2,

WGIII 8.3.1, WGIII 8.3.4, WGIII 8.4.1, WGIII 8.6}

Scaling-up climate action may generate disruptive changes in

economic structure with distributional consequences and need

to reconcile divergent interests, values and worldviews, within

and between countries. Deeper ﬁscal, ﬁnancial, institutional and

regulatory reforms can offset such adverse effects and unlock mitigation

potentials. Societal choices and actions implemented in this decade will

determine the extent to which medium and long-term development

pathways will deliver higher or lower climate resilient development

outcomes. (high conﬁdence) {WGII SPM D.2, WGII SPM D.5, WGII Box TS.8;

WGIII SPM D.3, WGIII SPM E.2, WGIII SPM E.3, WGIII SPM E.4, WGIII TS.2,

WGIII TS.4.1, WGIII TS.6.4, WGIII 15.2, WGIII 15.6}

Enabling conditions would need to be strengthened in the near-

term and barriers reduced or removed to realise opportunities

for deep and rapid adaptation and mitigation actions and

climate resilient development (high conﬁdence) (Figure 4.2).

These enabling conditions are differentiated by national, regional

and local circumstances and geographies, according to capabilities,

and include: equity and inclusion in climate action (see Section 4.4),

rapid and far-reaching transitions in sectors and system (see Section

4.5), measures to achieve synergies and reduce trade-

offs with sustainable development goals (see Section 4.6),

governance and policy improvements (see Section 4.7), access

to finance, improved international cooperation and technology

improvements (see Section 4.8), and integration of near-term

actions across sectors, systems and regions (see Section 4.9).

{WGII SPM D.2; WGIII SPM E.1, WGIII SPM E.2}

Barriers to feasibility would need to be reduced or removed

to deploy mitigation and adaptation options at scale. Many

limits to feasibility and effectiveness of responses can be overcome

by addressing a range of barriers, including economic, technological,

institutional, social, environmental and geophysical barriers. The

feasibility and effectiveness of options increase with integrated,

multi-sectoral solutions that differentiate responses based on climate

risk, cut across systems and address social inequities. Strengthened

near-term actions in modelled cost-effective pathways that limit global

warming to 2°C or lower, reduce the overall risk to the feasibility of the

system transitions, compared to modelled pathways with delayed or

uncoordinated action. (high conﬁdence) {WGII SPM C.2, WGII SPM C.3,

WGII SPM C.5; WGIII SPM E.1, WGIII SPM E.1.3}

Integrating ambitious climate actions with macroeconomic

policies under global uncertainty would provide benefits

(high confidence). This encompasses three main directions:

(a) economy-wide mainstreaming packages supporting options to

improved sustainable low-emission economic recovery, development

and job creation programs (Sections 4.4, 4.5, 4.6, 4.8, 4.9) (b) safety

nets and social protection in the transition (Section 4.4, 4.7); and

and coordinated support to low-emission infrastructure (‘leap-frog’

potential), especially in developing regions, and under debt stress

(high conﬁdence). (Section 4.8) {WGII SPM C.2, WGII SPM C.4.1,

WGII SPM D.1.3, WGII SPM D.2, WGII SPM D.3.2, WGII SPM E.2.2,

WGII SPM E.4, WGII SPM TS.2, WGII SPM TS.5.2, WGII TS.6.4,

WGII TS.15, WGII TS Box TS.3; WGIII SPM B.4.2, WGIII SPM C.5.4,

WGIII SPM C.6.2, WGIII SPM C.12.2, WGIII SPM D.3.4, WGIII SPM E.4.2,

WGIII SPM E.4.5, WGIII SPM E.5.2, WGIII SPM E.5.3, WGIII TS.1, WGIII Box TS.15,

WGIII 15.2, WGIII Cross-Chapter Box 1 on COVID in Chapter 1}

Near-Term Responses in a Changing Climate

Section 4

Climate Resilient Development

Emissions reductions

Adaptation

Sustainable Development

Multiple interacting choices and actions can shift

development pathways towards sustainability

Sustainable Development

Goal (SDG) achievement

IPCC AR6

2030

Present

world

Past

conditions

There is a rapidly narrowing window of opportunity

to enable climate resilient development

Prospects for climate

resilient development will

be further limited if global

warming exceeds 1.5°C and

if progress towards the SDGs

is inadequate

Early action and enabling

conditions create future

opportunities for climate

resilient development

Past conditions

(emissions, climate

change, development)

have increased warming

and development gaps persist

Illustrative ‘shock’ that

disrupts development

Low emissions

System transitions

Transformation

Low climate risk

Equity and justice

SDG achievement

High emissions

Entrenched systems

Adaptation limits

Maladaptation

Increasing climate risk

Reduced options

for development

Ecosystem

degradation

Outcomes characterising

development pathways

Civil

society

Governments

Private

sector

Conditions that enable

individual and collective actions

• Inclusive governance

• Diverse knowledges and values

• Finance and innovation

• Integration across sectors

and time scales

• Ecosystem stewardship

• Synergies between climate

and development actions

• Behavioural change supported

by policy, infrastructure and

socio-cultural factors

Conditions that constrain

individual and collective actions

• Poverty, inequity and injustice

• Economic, institutional, social

and capacity barriers

• Siloed responses

• Lack of ﬁnance, and barriers

to ﬁnance and technology

• Tradeoffs with SDGs

2100

& beyond

Figure 4.2: The illustrative development pathways (red to green) and associated outcomes (right panel) show that there is a rapidly narrowing window of

opportunity to secure a liveable and sustainable future for all. Climate resilient development is the process of implementing greenhouse gas mitigation and adaptation

measures to support sustainable development. Diverging pathways illustrate that interacting choices and actions made by diverse government, private sector and civil society actors

can advance climate resilient development, shift pathways towards sustainability, and enable lower emissions and adaptation. Diverse knowledges and values include cultural values,

Indigenous Knowledge, local knowledge, and scientiﬁc knowledge. Climatic and non-climatic events, such as droughts, ﬂoods or pandemics, pose more severe shocks to pathways

with lower climate resilient development (red to yellow) than to pathways with higher climate resilient development (green). There are limits to adaptation and adaptive capacity

for some human and natural systems at global warming of 1.5°C, and with every increment of warming, losses and damages will increase. The development pathways taken by

countries at all stages of economic development impact GHG emissions and hence shape mitigation challenges and opportunities, which vary across countries and regions.

Pathways and opportunities for action are shaped by previous actions (or inactions and opportunities missed, dashed pathway), and enabling and constraining conditions

(left panel), and take place in the context of climate risks, adaptation limits and development gaps. The longer emissions reductions are delayed, the fewer effective

adaptation options. {WGI SPM B.1; WGII SPM B.1 to B.5, WGII SPM C.2 to 5, WGII SPM D.1 to 5, WGII Figure SPM.3, WGII Figure SPM.4, WGII Figure SPM.5, WGII TS.D.5, WGII 3.1,

WGII 3.2, WGII 3.4, WGII 4.2, WGII Figure 4.4, WGII 4.5, WGII 4.6, WGII 4.9; WGIII SPM A, WGIII SPM B1, WGIII SPM B.3, WGIII SPM B.6, WGIII SPM C.4, WGIII SPM D1 to 3,

WGIII SPM E.1, WGIII SPM E.2, WGIII SPM E.4, WGIII SPM E.5, WGIII Figure TS.1, WGIII Figure TS.7, WGIII Box TS.3, WGIII Box TS.8, Cross-Working Group Box 1 in Chapter 3,

WGIII Cross-Chapter Box 5 in Chapter 4; SR1.5 SPM D.1 to 6; SRCCL SPM D.3}

4.3 Near-Term Risks

Many changes in the climate system, including extreme events, will become larger in the near term with increasing

global warming (high conﬁdence). Multiple climatic and non-climatic risks will interact, resulting in increased

compounding and cascading impacts becoming more difﬁcult to manage (high conﬁdence). Losses and damages

will increase with increasing global warming (very high conﬁdence), while strongly concentrated among the

poorest vulnerable populations (high conﬁdence). Continuing with current unsustainable development patterns

would increase exposure and vulnerability of ecosystems and people to climate hazards (high conﬁdence).

Section 4

Section 1

Section 4

Global warming will continue to increase in the near term (2021–2040)

mainly due to increased cumulative CO

emissions in nearly all

considered scenarios and pathways. In the near term, every

region in the world is projected to face further increases in

climate hazards (medium to high conﬁdence, depending on

region and hazard), increasing multiple risks to ecosystems

and humans (very high conﬁdence). In the near term, natural

variability

149

will modulate human-caused changes, either attenuating

or amplifying projected changes, especially at regional scales, with little

effect on centennial global warming. Those modulations are important

to consider in adaptation planning. Global surface temperature in any

single year can vary above or below the long-term human-induced

trend, due to natural variability. By 2030, global surface temperature

in any individual year could exceed 1.5°C relative to 1850–1900 with a

probability between 40% and 60%, across the five scenarios assessed

in WGI (medium confidence). The occurrence of individual years with

global surface temperature change above a certain level does not

imply that this global warming level has been reached. If a large

explosive volcanic eruption were to occur in the near term

150

, it

would temporarily and partially mask human-caused climate change

by reducing global surface temperature and precipitation, especially

over land, for one to three years (medium conﬁdence). {WGI SPM B.1.3,

WGI SPM B.1.4, WGI SPM C.1, WGI SPM C.2, WGI Cross-Section Box TS.1,

WGI Cross-Chapter Box 4.1; WGII SPM B.3, WGII SPM B.3.1;

WGIII Box SPM.1 Figure 1}

The level of risk for humans and ecosystems will depend on near-term

trends in vulnerability, exposure, level of socio-economic

development and adaptation (high conﬁdence). In the near term,

many climate-associated risks to natural and human systems depend

more strongly on changes in these systems’ vulnerability and exposure

than on differences in climate hazards between emissions scenarios

(high conﬁdence). Future exposure to climatic hazards is increasing

globally due to socio-economic development trends including growing

inequality, and when urbanisation or migration increase exposure

(high conﬁdence). Urbanisation increases hot extremes (very high

conﬁdence) and precipitation runoff intensity (high conﬁdence).

Increasing urbanisation in low-lying and coastal zones will be a major

driver of increasing exposure to extreme riverﬂow events and sea level

rise hazards, increasing risks (high conﬁdence) (Figure 4.3). Vulnerability

will also rise rapidly in low-lying Small Island Developing States and

atolls in the context of sea level rise (high conﬁdence) (see Figure 3.4 and

Figure 4.3). Human vulnerability will concentrate in informal settlements

and rapidly growing smaller settlements; and vulnerability in rural

areas will be heightened by reduced habitability and high reliance on

climate-sensitive livelihoods (high conﬁdence). Human and ecosystem

vulnerability are interdependent (high conﬁdence). Vulnerability to

climate change for ecosystems will be strongly inﬂuenced by past,

present, and future patterns of human development, including from

unsustainable consumption and production, increasing demographic

pressures, and persistent unsustainable use and management of

149

See Annex I: Glossary. The main internal variability phenomena include El Niño–Southern Oscillation, Paciﬁc Decadal Variability and Atlantic Multi-decadal Variability through

their regional influence. The internal variability of global surface temperature in any single year is estimated to be about ±0.25°C (5 to 95% range, high confidence).

{WGI SPM footnote 29, WGI SPM footnote 37}

150

Based on 2500-year reconstructions, eruptions with a radiative forcing more negative than –1 Wm

-2

, related to the radiative effect of volcanic stratospheric aerosols in the

literature assessed in this report, occur on average twice per century. {WGI SPM footnote 38}

land, ocean, and water (high conﬁdence). Several near-term risks can

be moderated with adaptation (high conﬁdence). {WGI SPM C.2.6;

WGII SPM B.2, WGII SPM B.2.3, WGII SPM B.2.5, WGII SPM B.3,

WGII SPM B.3.2, WGII TS.C.5.2} (Section 4.5 and 3.2)

Principal hazards and associated risks expected in the near term

(at 1.5°C global warming) are:

• Increased intensity and frequency of hot extremes and dangerous

heat-humidity conditions, with increased human mortality, morbidity,

and labour productivity loss (high conﬁdence). {WGI SPM B.2.2,

WGI TS Figure TS.6; WGII SPM B.1.4, WGII SPM B.4.4,

WGII Figure SPM.2}

• Increasing frequency of marine heatwaves will increase risks

of biodiversity loss in the oceans, including from mass mortality

events (high conﬁdence). {WGI SPM B.2.3; WGII SPM B.1.2,

WGII Figure SPM.2; SROCC SPM B.5.1}

• Near-term risks for biodiversity loss are moderate to high in

forest ecosystems (medium conﬁdence) and kelp and seagrass

ecosystems (high to very high conﬁdence) and are high to very

high in Arctic sea-ice and terrestrial ecosystems (high conﬁdence)

and warm-water coral reefs (very high conﬁdence). {WGII SPM B.3.1}

• More intense and frequent extreme rainfall and associated ﬂooding

in many regions including coastal and other low-lying cities

(medium to high conﬁdence), and increased proportion of and

peak wind speeds of intense tropical cyclones (high conﬁdence).

{WGI SPM B.2.4, WGI SPM C.2.2, WGI SPM C.2.6, WGI 11.7}

• High risks from dryland water scarcity, wildﬁre damage, and

permafrost degradation (medium conﬁdence). {SRCCL SPM A.5.3.}

• Continued sea level rise and increased frequency and

magnitude of extreme sea level events encroaching on coastal

human settlements and damaging coastal infrastructure (high

conﬁdence), committing low-lying coastal ecosystems to

submergence and loss (medium conﬁdence), expanding land

salinization (very high conﬁdence), with cascading to risks to

livelihoods, health, well-being, cultural values, food and water

security (high conﬁdence). {WGI SPM C.2.5, WGI SPM C.2.6;

WGII SPM B.3.1, WGII SPM B.5.2; SRCCL SPM A.5.6; SROCC SPM B.3.4,

SROCC SPM 3.6, SROCC SPM B.9.1} (Figure 3.4, 4.3)

• Climate change will signiﬁcantly increase ill health and premature

deaths from the near to long term (high conﬁdence). Further

warming will increase climate-sensitive food-borne, water-borne,

and vector-borne disease risks (high conﬁdence), and mental health

challenges including anxiety and stress (very high conﬁdence).

{WGII SPM B.4.4}

Near-Term Responses in a Changing Climate

Section 4

• Cryosphere-related changes in ﬂoods, landslides, and water

availability have the potential to lead to severe consequences for

people, infrastructure and the economy in most mountain regions

(high conﬁdence). {WGII TS C.4.2}

• The projected increase in frequency and intensity of heavy

precipitation (high conﬁdence) will increase rain-generated local

ﬂooding (medium conﬁdence). {WGI Figure SPM.6, WGI SPM B.2.2;

WGII TS C.4.5}

Multiple climate change risks will increasingly compound and

cascade in the near term (high conﬁdence). Many regions are

projected to experience an increase in the probability of compound

events with higher global warming (high conﬁdence) including

concurrent heatwaves and drought. Risks to health and food

production will be made more severe from the interaction of sudden

food production losses from heat and drought, exacerbated by heat-

induced labour productivity losses (high conﬁdence) (Figure 4.3). These

interacting impacts will increase food prices, reduce household incomes,

and lead to health risks of malnutrition and climate-related mortality

with no or low levels of adaptation, especially in tropical regions (high

conﬁdence). Concurrent and cascading risks from climate change to

food systems, human settlements, infrastructure and health will make

these risks more severe and more difﬁcult to manage, including when

interacting with non-climatic risk drivers such as competition for land

between urban expansion and food production, and pandemics (high

conﬁdence). Loss of ecosystems and their services has cascading and

long-term impacts on people globally, especially for Indigenous Peoples

and local communities who are directly dependent on ecosystems, to

meet basic needs (high conﬁdence). Increasing transboundary risks

are projected across the food, energy and water sectors as impacts

from weather and climate extremes propagate through supply-chains,

markets, and natural resource ﬂows (high conﬁdence) and may interact

with impacts from other crises such as pandemics. Risks also arise from

some responses intended to reduce the risks of climate change, including

risks from maladaptation and adverse side effects of some emissions

reduction and carbon dioxide removal measures, such as afforestation of

naturally unforested land or poorly implemented bioenergy compounding

climate-related risks to biodiversity, food and water security, and

livelihoods (high conﬁdence) (see Section 3.4.1 and 4.5). {WGI SPM.2.7;

WGII SPM B.2.1, WGII SPM B.5, WGII SPM B.5.1, WGII SPM B.5.2,

WGII SPM B.5.3,

WGII SPM B.5.4,

WGII Cross-Chapter Box COVID in Chapter 7;

WGIII SPM C.11.2; SRCCL SPM A.5, SRCCL SPM A.6.5

}

(Figure 4.3

)

With every increment of global warming losses and damages will

increase (very high conﬁdence), become increasingly difﬁcult

to avoid and be strongly concentrated among the poorest

vulnerable populations (high conﬁdence). Adaptation does not

prevent all losses and damages, even with effective adaptation and

before reaching soft and hard limits. Losses and damages will be

unequally distributed across systems, regions and sectors and are

not comprehensively addressed by current ﬁnancial, governance and

institutional arrangements, particularly in vulnerable developing

countries. (high conﬁdence). {WGII SPM B.4, WGII SPM C.3, WGII SPM C.3.5}

100

Section 4

Section 1

Section 4

absolute increase

(and percent increase)

Every region faces more severe and/or frequent compound

and cascading climate risks

a) Increase in the population exposed to sea level rise from 2020 to 2040

Frequency of events that currently occur

on average once every 100 years

Multiple climate change risks

will increasingly compound

and cascade in the near term

c) Example of complex risk, where impacts from climate extreme events have cascading

effects on food, nutrition, livelihoods and well-being of smallholder farmers

Food yield

and quality losses

Food prices

increase

Reduced labour

capacity

Reduced

food security

Decreased

quality of life

Increased malnutrition

(particularly maternal malnutrition

and child undernutrition)

Reduced soil moisture

and health

Bi-directional

compounding

Uni-directional

compounding or domino

Contagion effect on

multiple risks

Reduced household

income

Key

Extreme heat and drought

Exposure to a coastal ﬂooding event that

currently occurs on average once every 100 years

More frequent and more intense

Annual event

Twice-a-century event

No change

Decadal event

b) Increased frequency of extreme

sea level events by 2040

Africa

Asia

Australasia

Central and

South America

Europe

North America

Small Islands

0.10 million (57%)

0.18 million

0.34 million

0.69 million

2.40 million

0.38 million (57%)

0.67 million

63.81 million

0.01 million (52%)

0.02 million

16.36 million (26%)

2.29 million (95%)

0.24 million (35%)

0.24 million (71%)

Increase due to sea level rise only

Increase due to sea level rise and population change

Population exposed in 2020

SSP2-4.5

Additional population exposed in 2040

0.1

million

The absence of a circle indicates an inability to perform

an assessment due to a lack of data.

Projected change to

1-in-100 year events

under the intermediate

SSP2-4.5 scenario

101

Near-Term Responses in a Changing Climate

Section 4

Figure 4.3: Every region faces more severe or frequent compound and/or cascading climate risks in the near term. Changes in risk result from changes in the degree

of the hazard, the population exposed, and the degree of vulnerability of people, assets, or ecosystems. Panel (a) Coastal ﬂooding events affect many of the highly populated regions

of the world where large percentages of the population are exposed.The panel shows near-term projected increase of population exposed to 100-year ﬂooding events depicted

as the increase from the year 2020 to 2040 (due to sea level rise and population change), based on the intermediate GHG emissions scenario (SSP2-4.5) and current adaptation

measures. Out-migration from coastal areas due to future sea level rise is not considered in the scenario. Panel (b) projected median probability in the year 2040 for extreme water

levels resulting from a combination of mean sea level rise, tides and storm surges, which have a historical 1% average annual probability. A peak-over-threshold (99.7%) method

was applied to the historical tide gauge observations available in the Global Extreme Sea Level Analysis version 2 database, which is the same information as WGI Figure 9.32,

except here the panel uses relative sea level projections under SSP2-4.5 for the year 2040 instead of 2050 The absence of a circle indicates an inability to perform an assessment

due to a lack of data, but does not indicate absence of increasing frequencies. Panel (c) Climate hazards can initiate risk cascades that affect multiple sectors and propagate across

regions following complex natural and societal connections. This example of a compound heat wave and a drought event striking an agricultural region shows how multiple risks are

interconnected and lead to cascading biophysical, economic, and societal impacts even in distant regions, with vulnerable groups such as smallholder farmers, children and pregnant

women particularly impacted. {WGI Figure 9.32; WGII SPM B4.3, WGII SPM B1.3, WGII SPM B.5.1, WGII TS Figure TS.9, WGII TS Figure TS.10 (c), WGII Fig 5.2, WGII TS.B.2.3,

WGII TS.B.2.3, WGII TS.B.3.3, WGII 9.11.1.2}

Actions that prioritise equity, climate justice, social justice and inclusion lead to more sustainable outcomes,

co-beneﬁts, reduce trade-offs, support transformative change and advance climate resilient development.

Adaptation responses are immediately needed to reduce rising climate risks, especially for the most vulnerable.

Equity, inclusion and just transitions are key to progress on adaptation and deeper societal ambitions for

accelerated mitigation. (high conﬁdence)

Adaptation and mitigation actions, across scales, sectors and

regions, that prioritise equity, climate justice, rights-based

approaches, social justice and inclusivity, lead to more

sustainable outcomes, reduce trade-offs, support transformative

change and advance climate resilient development (high

conﬁdence). Redistributive policies across sectors and regions that

shield the poor and vulnerable, social safety nets, equity, inclusion

and just transitions, at all scales can enable deeper societal ambitions

and resolve trade-offs with sustainable development goals.(SDGs),

particularly education, hunger, poverty, gender and energy access (high

conﬁdence). Mitigation efforts embedded within the wider development

context can increase the pace, depth and breadth of emission reductions

(medium conﬁdence). Equity, inclusion and just transitions at all

scales enable deeper societal ambitions for accelerated mitigation,

and climate action more broadly (high conﬁdence). The complexity in

risk of rising food prices, reduced household incomes, and health and

climate-related malnutrition (particularly maternal malnutrition and

child undernutrition) and mortality increases with little or low levels

of adaptation (high conﬁdence). {WGII SPM B.5.1, WGII SPM C.2.9,

WGII SPM D.2.1, WGII TS Box TS.4; WGIII SPM D.3, WGIII SPM D.3.3,

WGIII SPM WGIII SPM E.3, SR1.5 SPM D.4.5} (Figure 4.3c)

Regions and people with considerable development constraints

have high vulnerability to climatic hazards. Adaptation

outcomes for the most vulnerable within and across countries

and regions are enhanced through approaches focusing on

equity, inclusivity, and rights-based approaches, including 3.3 to

3.6 billion people living in contexts that are highly vulnerable

to climate change (high conﬁdence). Vulnerability is higher in

locations with poverty, governance challenges and limited access

to basic services and resources, violent conﬂict and high levels of

climate-sensitive livelihoods (e.g., smallholder farmers, pastoralists,

ﬁshing communities) (high conﬁdence). Several risks can be moderated

with adaptation (high conﬁdence). The largest adaptation gaps

exist among lower income population groups (high conﬁdence) and

adaptation progress is unevenly distributed with observed adaptation

gaps (high conﬁdence). Present development challenges causing high

vulnerability are inﬂuenced by historical and ongoing patterns of

inequity such as colonialism, especially for many Indigenous Peoples

and local communities (high conﬁdence). Vulnerability is exacerbated

by inequity and marginalisation linked to gender, ethnicity, low income

or combinations thereof, especially for many Indigenous Peoples and

local communities (high conﬁdence). {WGII SPM B.2, WGII SPM B.2.4,

WGII SPM B.3.2, WGII SPM B.3.3, WGII SPM C.1, WGII SPM C.1.2,

WGII SPM C.2.9}

Meaningful participation and inclusive planning, informed by

cultural values, Indigenous Knowledge, local knowledge, and

scientiﬁc knowledge can help address adaptation gaps and

avoid maladaptation (high conﬁdence). Such actions with ﬂexible

pathways may encourage low-regret and timely actions (very high

conﬁdence). Integrating climate adaptation into social protection

programmes, including cash transfers and public works programmes,

would increase resilience to climate change, especially when supported

by basic services and infrastructure (high conﬁdence). {WGII SPM C.2.3,

WGII SPM C.4.3, WGII SPM C.4.4, WGII SPM C.2.9, WGII WPM D.3}

Equity, inclusion, just transitions, broad and meaningful

participation of all relevant actors in decision making at

all scales enable deeper societal ambitions for accelerated

mitigation, and climate action more broadly, and build social

trust, support transformative changes and an equitable sharing

of beneﬁts and burdens (high conﬁdence). Equity remains a

central element in the UN climate regime, notwithstanding shifts

in differentiation between states over time and challenges in

assessing fair shares. Ambitious mitigation pathways imply large and

sometimes disruptive changes in economic structure, with signiﬁcant

distributional consequences, within and between countries, including

shifting of income and employment during the transition from high to

low emissions activities (high conﬁdence). While some jobs may be lost,

low-emissions development can also open up opportunities to enhance

skills and create jobs (high conﬁdence). Broadening equitable access

to ﬁnance, technologies and governance that facilitate mitigation, and

consideration of climate justice can help equitable sharing of beneﬁts

4.4 Equity and Inclusion in Climate Change Action

102

Section 4

Section 1

Section 4

and burdens, especially for vulnerable countries and communities.

{WGIII SPM D.3, WGIII SPM D.3.2, WGIII SPM D.3.3, WGIII SPM D.3.4,

WGIII TS Box TS.4}

Development priorities among countries also reﬂect different

starting points and contexts, and enabling conditions for

shifting development pathways towards increased sustainability

will therefore differ, giving rise to different needs (high

conﬁdence). Implementing just transition principles through collective

and participatory decision-making processes is an effective way of

integrating equity principles into policies at all scales depending

on national circumstances, while in several countries just transition

commissions, task forces and national policies have been established

(medium conﬁdence). {WGIII SPM D.3.1, WGIII SPM D.3.3}

Many economic and regulatory instruments have been

effective in reducing emissions and practical experience has

informed instrument design to improve them while addressing

distributional goals and social acceptance (high conﬁdence). The

design of behavioural interventions, including the way that choices are

presented to consumers work synergistically with price signals, making

the combination more effective (medium conﬁdence). Individuals with

high socio-economic status contribute disproportionately to emissions,

and have the highest potential for emissions reductions, e.g., as

citizens, investors, consumers, role models, and professionals (high

conﬁdence). There are options on design of instruments such as taxes,

subsidies, prices, and consumption-based approaches, complemented

by regulatory instruments to reduce high-emissions consumption while

improving equity and societal well-being (high conﬁdence). Behaviour

and lifestyle changes to help end-users adopt low-GHG-intensive

options can be supported by policies, infrastructure and technology

with multiple co-beneﬁts for societal well-being (high conﬁdence).

Broadening equitable access to domestic and international ﬁnance,

technologies and capacity can also act as a catalyst for accelerating

mitigation and shifting development pathways in low-income contexts

(high conﬁdence). Eradicating extreme poverty, energy poverty, and

providing decent living standards to all in these regions in the context of

achieving sustainable development objectives, in the near term, can be

achieved without signiﬁcant global emissions growth (high conﬁdence).

Technology development, transfer, capacity building and ﬁnancing can

support developing countries/ regions leapfrogging or transitioning to

low-emissions transport systems thereby providing multiple co-beneﬁts

(high conﬁdence). Climate resilient development is advanced when

actors work in equitable, just and enabling ways to reconcile divergent

interests, values and worldviews, toward equitable and just outcomes

(high conﬁdence). {WGII D.2.1, WGIII SPM B.3.3, WGIII SPM.C.8.5, WGIII

SPM C.10.2, WGIII SPM C.10.4, WGIII SPM D.3.4, WGIII SPM E.4.2,

WGIII TS.5.1, WGIII 5.4, WGIII 5.8, WGIII 15.2}

Rapid and far-reaching transitions across all sectors and systems

are necessary to achieve deep emissions reductions and secure

a liveable and sustainable future for all (high conﬁdence). System

transitions

151

consistent with pathways that limit warming to 1.5°C

(>50%) with no or limited overshoot are more rapid and pronounced

in the near-term than in those that limit warming to 2°C (>67%)

(high conﬁdence). Such a systemic change is unprecedented in terms

of scale, but not necessarily in terms of speed (medium conﬁdence).

The system transitions make possible the transformative adaptation

required for high levels of human health and well-being, economic and

social resilience, ecosystem health, and planetary health. {WGII SPM

A, WGII Figure SPM.1; WGIII SPM C.3; SR1.5 SPM C.2, SR1.5 SPM

C.2.1, SR1.5 SPM C.2, SR1.5 SPM C.5}

Feasible, effective and low-cost options for mitigation and

adaptation are already available (high conﬁdence) (Figure 4.4).

Mitigation options costing USD 100 tCO

-eq

–1

or less could reduce

151

System transitions involve a wide portfolio of mitigation and adaptation options that enable deep emissions reductions and transformative adaptation in all sectors. This report

has a particular focus on the following system transitions: energy; industry; cities, settlements and infrastructure; land, ocean, food and water; health and nutrition; and society,

livelihood and economies. {WGII SPM A, WGII Figure SPM.1, WGII Figure SPM.4; SR1.5 SPM C.2}

152

See Annex I: Glossary.

global GHG emissions by at least half the 2019 level by 2030 (options

costing less than USD 20 tCO

-eq

–1

are estimated to make up more

than half of this potential) (high conﬁdence) (Figure 4.4). The

availability, feasibility

152

and potential of mitigation or effectiveness

of adaptation options in the near term differ across systems and

regions (very high confidence). {WGII SPM C.2; WGIII SPM C.12,

WGIII SPM E.1.1; SR1.5 SPM B.6}

Demand-side measures and new ways of end-use service

provision can reduce global GHG emissions in end-use sectors by

40 to 70% by 2050 compared to baseline scenarios, while some

regions and socioeconomic groups require additional energy

and resources. Demand-side mitigation encompasses changes in

infrastructure use, end-use technology adoption, and socio-cultural and

behavioural change. (high conﬁdence) (Figure 4.4). {WGIII SPM C.10}

4.5 Near-Term Mitigation and Adaptation Actions

Rapid and far-reaching transitions across all sectors and systems are necessary to achieve deep and sustained

emissions reductions and secure a liveable and sustainable future for all. These system transitions involve a

signiﬁcant upscaling of a wide portfolio of mitigation and adaptation options. Feasible, effective and low-cost

options for mitigation and adaptation are already available, with differences across systems and regions. (high

conﬁdence)

103

Near-Term Responses in a Changing Climate

Section 4

There are multiple opportunities for scaling up climate action

Costs are lower than the reference

0–20 (USD per tCO

-eq)

20–50 (USD per tCO

-eq)

50–100 (USD per tCO

-eq)

100–200 (USD per tCO

-eq)

Cost not allocated due to high

variability or lack of data

Net lifetime cost of options:

Feasibility level and synergies

with mitigation

Insufﬁcient evidence

Conﬁdence level in potential feasibility

and in synergies with mitigation

MediumHigh Low

a) Feasibility of climate responses and adaptation, and potential of mitigation options in the near term

High Medium Low

Synergies

with

mitigation

not

assessed

0 1 2 3 4 5

Potential contribution to

net emission reduction, 2030

Carbon capture with

utilisation (CCU) and CCS

Material efﬁciency

Enhanced recycling

Construction materials substitution

Energy efﬁciency

Wind

Solar

Reduce methane and N

O in agriculture

Reduce food loss and food waste

Geothermal and hydropower

Carbon sequestration in agriculture

Reduce conversion of natural ecosystems

Nuclear

Reduce methane from coal, oil and gas

Bioelectricity (includes BECCS)

Fossil Carbon Capture and Storage (CCS)

Ecosystem restoration,

afforestation, reforestation

Fuel switching

Reduce emission of ﬂuorinated gas

Reduce methane from

waste/wastewater

Improved sustainable forest management

Climate responses and

adaptation options

Mitigation options

GtCO

-eq/yr

Enhanced health services

(e.g. WASH, nutrition and diets)

Green infrastructure and

ecosystem services

Sustainable land use and urban planning

Sustainable urban water management

Climate services, including

Early Warning Systems

Livelihood diversiﬁcation

Disaster risk management

Social safety nets

Risk spreading and sharing

Planned relocation and resettlement

Human migration

Agroforestry

Sustainable aquaculture and ﬁsheries

Efﬁcient livestock systems

Biodiversity management and

ecosystem connectivity

Integrated coastal zone management

Water use efﬁciency and water

resource management

Improved cropland management

Coastal defence and hardening

Forest-based adaptation

Resilient power systems

Energy reliability (e.g.

diversiﬁcation, access, stability)

Improve water use efﬁciency

Potential

feasibility

up to 1.5°C

ENERGY SUPPLY

LAND, WATER, FOOD

HEALTH

SETTLEMENTS

AND

INFRASTRUCTURE

SOCIETY, LIVELIHOOD

AND ECONOMY

INDUSTRY AND WASTE

100

Electricity

Land transport

Buildings

Industry

Food

67%

66%

29%

44%

73% reduction (before

additional electriﬁcation)

Additional electriﬁcation (+60%)

GtCO

-eq/yr

GtCO

/yr

Key

Total emissions (2050)

Percentage of possible reduction

Demand-side mitigation potential

Potential range

Efﬁcient lighting, appliances

and equipment

Efﬁcient shipping and aviation

Avoid demand for energy services

Efﬁcient buildings

Electric vehicles

Public transport and bicycling

Biofuels for transport

Onsite renewables

Fuel efﬁcient vehicles

Shift to sustainable healthy diets

options costing 100 USD tCO

-eq

-1

less could reduce global emissions by

at least half of the 2019 level by 2030

b) Potential of demand-side

mitigation options by 2050

the range of GHG emissions

reduction potential is 40-70%

in these end-use sectors

104

Section 4

Section 1

Section 4

Figure 4.4: Multiple Opportunities for scaling up climate action. Panel (a) presents selected mitigation and adaptation options across different systems. The left hand side

of panel (a) shows climate responses and adaptation options assessed for their multidimensional feasibility at global scale, in the near term and up to 1.5°C global warming. As

literature above 1.5°C is limited, feasibility at higher levels of warming may change, which is currently not possible to assess robustly. The term response is used here in addition to

adaptation because some responses, such as migration, relocation and resettlement may or may not be considered to be adaptation. Migration, when voluntary, safe and orderly,

allows reduction of risks to climatic and non-climatic stressors. Forest based adaptation includes sustainable forest management, forest conservation and restoration, reforestation

and afforestation. WASH refers to water, sanitation and hygiene. Six feasibility dimensions (economic, technological, institutional, social, environmental and geophysical) were used

to calculate the potential feasibility of climate responses and adaptation options, along with their synergies with mitigation. For potential feasibility and feasibility dimensions, the

ﬁgure shows high, medium, or low feasibility. Synergies with mitigation are identiﬁed as high, medium, and low. The right-hand side of panel (a) provides an overview of selected

mitigation options and their estimated costs and potentials in 2030. Relative potentials and costs will vary by place, context and time and in the longer term compared to 2030. Costs

are net lifetime discounted monetary costs of avoided greenhouse gas emissions calculated relative to a reference technology. The potential (horizontal axis) is the quantity of net

GHG emission reduction that can be achieved by a given mitigation option relative to a speciﬁed emission baseline. Net GHG emission reductions are the sum of reduced emissions

and/or enhanced sinks. The baseline used consists of current policy (around 2019) reference scenarios from the AR6 scenarios database (25–75 percentile values). The mitigation

potentials are assessed independently for each option and are not necessarily additive. Health system mitigation options are included mostly in settlement and infrastructure

(e.g., efﬁcient healthcare buildings) and cannot be identiﬁed separately. Fuel switching in industry refers to switching to electricity, hydrogen, bioenergy and natural gas. The length

of the solid bars represents the mitigation potential of an option. Potentials are broken down into cost categories, indicated by different colours (see legend). Only discounted lifetime

monetary costs are considered. Where a gradual colour transition is shown, the breakdown of the potential into cost categories is not well known or depends heavily on factors such

as geographical location, resource availability, and regional circumstances, and the colours indicate the range of estimates. The uncertainty in the total potential is typically 25–50%.

When interpreting this ﬁgure, the following should be taken into account: (1) The mitigation potential is uncertain, as it will depend on the reference technology (and emissions)

being displaced, the rate of new technology adoption, and several other factors; (2) Different options have different feasibilities beyond the cost aspects, which are not reﬂected in

the ﬁgure; and (3) Costs for accommodating the integration of variable renewable energy sources in electricity systems are expected to be modest until 2030, and are not included.

Panel (b) displays the indicative potential of demand-side mitigation options for 2050. Potentials are estimated based on approximately 500 bottom-up studies representing all

global regions. The baseline (white bar) is provided by the sectoral mean GHG emissions in 2050 of the two scenarios (IEA-STEPS and IP_ModAct) consistent with policies announced

by national governments until 2020. The green arrow represents the demand-side emissions reductions potentials. The range in potential is shown by a line connecting dots displaying

the highest and the lowest potentials reported in the literature. Food shows demand-side potential of socio-cultural factors and infrastructure use, and changes in land-use patterns

enabled by change in food demand. Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end-use sectors (buildings, land transport,

food) by 40–70% by 2050 compared to baseline scenarios, while some regions and socioeconomic groups require additional energy and resources. The last row shows how demand-

side mitigation options in other sectors can inﬂuence overall electricity demand. The dark grey bar shows the projected increase in electricity demand above the 2050 baseline due

to increasing electriﬁcation in the other sectors. Based on a bottom-up assessment, this projected increase in electricity demand can be avoided through demand-side mitigation

options in the domains of infrastructure use and socio-cultural factors that inﬂuence electricity usage in industry, land transport, and buildings (green arrow). {WGII Figure SPM.4,

WGII Cross-Chapter Box FEASIB in Chapter 18; WGIII SPM C.10, WGIII 12.2.1, WGIII 12.2.2, WGIII Figure SPM.6, WGIII Figure SPM.7}

4.5.1. Energy Systems

Rapid and deep reductions in GHG emissions require major

energy system transitions (high conﬁdence). Adaptation options

can help reduce climate-related risks to the energy system

(very high conﬁdence). Net zero CO

energy systems entail: a

substantial reduction in overall fossil fuel use, minimal use of

unabated fossil fuels

153

, and use of Carbon Capture and Storage in

the remaining fossil fuel systems; electricity systems that emit no

net CO

; widespread electrification; alternative energy carriers in

applications less amenable to electrification; energy conservation

and efficiency; and greater integration across the energy system

(high confidence). Large contributions to emissions reductions can

come from options costing less than USD 20 tCO

-eq

–1

, including

solar and wind energy, energy efﬁciency improvements, and CH

(methane) emissions reductions (from coal mining, oil and gas, and

waste) (medium confidence).

154

Many of these response options are

technically viable and are supported by the public (high confidence).

Maintaining emission-intensive systems may, in some regions and

sectors, be more expensive than transitioning to low emission

systems (high confidence). {WGII SPM C.2.10; WGIII SPM C.4.1,

WGIII SPM C.4.2, WGIII SPM C.12.1, WGIII SPM E.1.1, WGIII TS.5.1}

Climate change and related extreme events will affect future energy

systems, including hydropower production, bioenergy yields, thermal

power plant efﬁciencies, and demands for heating and cooling (high

153

In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce the amount of GHG emitted throughout the life

cycle; for example, capturing 90% or more CO

from power plants, or 50–80% of fugitive methane emissions from energy supply. {WGIII SPM footnote 54}

154

The mitigation potentials and mitigation costs of individual technologies in a speciﬁc context or region may differ greatly from the provided estimates (medium conﬁdence).

{WGIII SPM C.12.1}

conﬁdence). The most feasible energy system adaptation options

support infrastructure resilience, reliable power systems and efﬁcient

water use for existing and new energy generation systems (very

high conﬁdence). Adaptations for hydropower and thermo-electric

power generation are effective in most regions up to 1.5°C to 2°C,

with decreasing effectiveness at higher levels of warming (medium

conﬁdence). Energy generation diversiﬁcation (e.g., wind, solar, small-

scale hydroelectric) and demand side management (e.g., storage and

energy efﬁciency improvements) can increase energy reliability and

reduce vulnerabilities to climate change, especially in rural populations

(high conﬁdence). Climate responsive energy markets, updated design

standards on energy assets according to current and projected climate

change, smart-grid technologies, robust transmission systems and

improved capacity to respond to supply deﬁcits have high feasibility

in the medium- to long-term, with mitigation co-beneﬁts (very high

conﬁdence). {WGII SPM B.5.3, WGII SPM C.2.10; WGIII TS.5.1}

4.5.2. Industry

There are several options to reduce industrial emissions

that differ by type of industry; many industries are disrupted

by climate change, especially from extreme events (high

conﬁdence). Reducing industry emissions will entail coordinated

action throughout value chains to promote all mitigation options,

including demand management, energy and materials efﬁciency,

circular material ﬂows, as well as abatement technologies and

105

Near-Term Responses in a Changing Climate

Section 4

transformational changes in production processes (high conﬁdence).

Light industry and manufacturing can be largely decarbonized through

available abatement technologies (e.g., material efﬁciency, circularity),

electriﬁcation (e.g., electrothermal heating, heat pumps), and switching

to low- and zero-GHG emitting fuels (e.g., hydrogen, ammonia, and

bio-based and other synthetic fuels) (high conﬁdence), while deep

reduction of cement process emissions will rely on cementitious

material substitution and the availability of Carbon Capture and Storage

(CCS) until new chemistries are mastered (high conﬁdence). Reducing

emissions from the production and use of chemicals would need to rely

on a life cycle approach, including increased plastics recycling, fuel and

feedstock switching, and carbon sourced through biogenic sources, and,

depending on availability, Carbon Capture and Utilisation (CCU), direct

air CO

capture, as well as CCS (high conﬁdence). Action to reduce

industry sector emissions may change the location of GHG-intensive

industries and the organisation of value chains, with distributional

effects on employment and economic structure (medium conﬁdence).

{WGII TS.B.9.1, WGII 16.5.2; WGIII SPM C.5, WGIII SPM C.5.2,

WGIII SPM C.5.3, WGIII TS.5.5}

Many industrial and service sectors are negatively affected by climate

change through supply and operational disruptions, especially from

extreme events (high conﬁdence), and will require adaptation efforts.

Water intensive industries (e.g., mining) can undertake measures to

reduce water stress, such as water recycling and reuse, using brackish

or saline sources, working to improve water use efﬁciency. However,

residual risks will remain, especially at higher levels of warming

(medium conﬁdence). {WGII TS.B.9.1, WGII 16.5.2, WGII 4.6.3} (Section 3.2)

4.5.3. Cities, Settlements and Infrastructure

Urban systems are critical for achieving deep emissions

reductions and advancing climate resilient development,

particularly when this involves integrated planning that

incorporates physical, natural and social infrastructure (high

conﬁdence). Deep emissions reductions and integrated adaptation

actions are advanced by: integrated, inclusive land use planning

and decision-making; compact urban form by co-locating jobs and

housing; reducing or changing urban energy and material consumption;

electriﬁcation in combination with low emissions sources; improved

water and waste management infrastructure; and enhancing carbon

uptake and storage in the urban environment (e.g. bio-based building

materials, permeable surfaces and urban green and blue infrastructure).

Cities can achieve net zero emissions if emissions are reduced within

and outside of their administrative boundaries through supply chains,

creating beneﬁcial cascading effects across other sectors. (high conﬁdence)

{WGII SPM C.5.6, WGII SPM D.1.3, WGII SPM D.3; WGIII SPM C.6, WGIII

SPM C.6.2, WGIII TS 5.4, SR1.5 SPM C.2.4}

Considering climate change impacts and risks (e.g., through climate

services) in the design and planning of urban and rural settlements

and infrastructure is critical for resilience and enhancing human

well-being. Effective mitigation can be advanced at each of the design,

construction, retroﬁt, use and disposal stages for buildings. Mitigation

interventions for buildings include: at the construction phase, low-

155

A set of measures and daily practices that avoid demand for energy, materials, land and water while delivering human well-being for all within planetary boundaries.

{WGIII Annex I}

emission construction materials, highly efﬁcient building envelope

and the integration of renewable energy solutions; at the use phase,

highly efﬁcient appliances/equipment, the optimisation of the use

of buildings and their supply with low-emission energy sources;

and at the disposal phase, recycling and re-using construction

materials. Sufﬁciency

155

measures can limit the demand for energy

and materials over the lifecycle of buildings and appliances. (high

conﬁdence) {WGII SPM C.2.5; WGIII SPM C.7.2}

Transport-related GHG emissions can be reduced by demand-side

options and low-GHG emissions technologies. Changes in urban form,

reallocation of street space for cycling and walking, digitalisation

(e.g., teleworking) and programs that encourage changes in consumer

behaviour (e.g. transport, pricing) can reduce demand for transport

services and support the shift to more energy efﬁcient transport

modes (high conﬁdence). Electric vehicles powered by low-emissions

electricity offer the largest decarbonisation potential for land-based

transport, on a life cycle basis (high conﬁdence). Costs of electriﬁed

vehicles are decreasing and their adoption is accelerating, but they

require continued investments in supporting infrastructure to increase

scale of deployment (high conﬁdence). The environmental footprint of

battery production and growing concerns about critical minerals can

be addressed by material and supply diversiﬁcation strategies, energy

and material efﬁciency improvements, and circular material ﬂows

(medium conﬁdence). Advances in battery technologies could facilitate

the electriﬁcation of heavy-duty trucks and compliment conventional

electric rail systems (medium conﬁdence). Sustainable biofuels can offer

additional mitigation beneﬁts in land-based transport in the short and

medium term (medium conﬁdence). Sustainable biofuels, low-emissions

hydrogen, and derivatives (including synthetic fuels) can support

mitigation of CO

emissions from shipping, aviation, and heavy-duty

land transport but require production process improvements and cost

reductions (medium conﬁdence). Key infrastructure systems including

sanitation, water, health, transport, communications and energy will

be increasingly vulnerable if design standards do not account for

changing climate conditions (high conﬁdence). {WGII SPM B.2.5;

WGIII SPM C.6.2, WGIII SPM C.8, WGIII SPM C.8.1, WGIII SPM C.8.2,

WGIII SPM C.10.2, WGIII SPM C.10.3, WGIII SPM C.10.4}

Green/natural and blue infrastructure such as urban forestry, green

roofs, ponds and lakes, and river restoration can mitigate climate change

through carbon uptake and storage, avoided emissions, and reduced

energy use while reducing risk from extreme events such as heatwaves,

heavy precipitation and droughts, and advancing co-beneﬁts for health,

well-being and livelihoods (medium conﬁdence). Urban greening can

provide local cooling (very high conﬁdence). Combining green/natural

and grey/physical infrastructure adaptation responses has potential

to reduce adaptation costs and contribute to ﬂood control, sanitation,

water resources management, landslide prevention and coastal

protection (medium conﬁdence). Globally, more ﬁnancing is directed

at grey/physical infrastructure than green/natural infrastructure

and social infrastructure (medium conﬁdence), and there is limited

evidence of investment in informal settlements (medium to high

conﬁdence). The greatest gains in well-being in urban areas can be

achieved by prioritising ﬁnance to reduce climate risk for low-income

106

Section 4

Section 1

Section 4

and marginalised communities including people living in informal

settlements (high conﬁdence). {WGII SPM C.2.5, WGII SPM C.2.6, WGII

SPM C.2.7, WGII SPM D.3.2, WGII TS.E.1.4, WGII Cross-Chapter Box FEAS;

WGIII SPM C.6, WGIII SPM C.6.2, WGIII SPM D.1.3, WGIII SPM D.2.1}

Responses to ongoing sea level rise and land subsidence in low-lying

coastal cities and settlements and small islands include protection,

accommodation, advance and planned relocation. These responses

are more effective if combined and/or sequenced, planned well ahead,

aligned with sociocultural values and development priorities, and

underpinned by inclusive community engagement processes. (high

conﬁdence) {WGII SPM C.2.8}

4.5.4. Land, Ocean, Food, and Water

There is substantial mitigation and adaptation potential from

options in agriculture, forestry and other land use, and in the

oceans, that could be upscaled in the near term across most

regions (high conﬁdence) (Figure 4.5). Conservation, improved

management, and restoration of forests and other ecosystems offer

the largest share of economic mitigation potential, with reduced

deforestation in tropical regions having the highest total mitigation

potential. Ecosystem restoration, reforestation, and afforestation can

lead to trade-offs due to competing demands on land. Minimizing

trade-offs requires integrated approaches to meet multiple objectives

including food security. Demand-side measures (shifting to sustainable

healthy diets and reducing food loss/waste) and sustainable agricultural

intensiﬁcation can reduce ecosystem conversion and CH

and N

O emissions,

and free up land for reforestation and ecosystem restoration.

Sustainably sourced agriculture and forest products, including

long-lived wood products, can be used instead of more GHG-intensive

products in other sectors. Effective adaptation options include cultivar

improvements, agroforestry, community-based adaptation, farm and

landscape diversiﬁcation, and urban agriculture. These AFOLU response

options require integration of biophysical, socioeconomic and other

enabling factors. The effectiveness of ecosystem-based adaptation

and most water-related adaptation options declines with increasing

warming (see 3.2). (high conﬁdence) {WGII SPM C.2.1, WGII SPM C.2.2,

WGII SPM C.2.5; WGIII SPM C.9.1; SRCCL SPM B.1.1, SRCCL SPM B.5.4,

SRCCL SPM D.1; SROCC SPM C}

Some options, such as conservation of high-carbon ecosystems

(e.g., peatlands, wetlands, rangelands, mangroves and forests), have

immediate impacts while others, such as restoration of high-carbon

ecosystems, reclamation of degraded soils or afforestation, take decades

to deliver measurable results (high conﬁdence). Many sustainable land

management technologies and practices are ﬁnancially proﬁtable in three

to ten years (medium conﬁdence). {SRCCL SPM B.1.2, SRCCL SPM D.2.2}

Maintaining the resilience of biodiversity and ecosystem

services at a global scale depends on effective and equitable

conservation of approximately 30–50% of Earth’s land,

freshwater and ocean areas, including currently near-natural

ecosystems (high conﬁdence). The services and options provided by

terrestrial, freshwater, coastal and ocean ecosystems can be supported

156

Balanced diets refer to diets that feature plant-based foods, such as those based on coarse grains, legumes, fruits and vegetables, nuts and seeds, and animal-sourced food

produced in resilient, sustainable and low-GHG emission systems, as described in SRCCL.

by protection, restoration, precautionary ecosystem-based management

of renewable resource use, and the reduction of pollution and other

stressors (high confidence). {WGII SPM C.2.4, WGII SPM D.4;

SROCC SPM C.2}

Large-scale land conversion for bioenergy, biochar, or afforestation

can increase risks to biodiversity, water and food security. In contrast,

restoring natural forests and drained peatlands, and improving

sustainability of managed forests enhances the resilience of carbon

stocks and sinks and reduces ecosystem vulnerability to climate change.

Cooperation, and inclusive decision making, with local communities

and Indigenous Peoples, as well as recognition of inherent rights of

Indigenous Peoples, is integral to successful adaptation across

forests and other ecosystems. (high confidence) {WGII SPM B.5.4,

WGII SPM C.2.3, WGII SPM C.2.4; WGIII SPM D.2.3; SRCCL B.7.3,

SRCCL SPM C.4.3, SRCCL TS.7}

Natural rivers, wetlands and upstream forests reduce ﬂood risk in most

circumstances (high conﬁdence). Enhancing natural water retention

such as by restoring wetlands and rivers, land use planning such as no

build zones or upstream forest management, can further reduce ﬂood risk

(medium conﬁdence). For inland ﬂooding, combinations of non-structural

measures like early warning systems and structural measures like levees

have reduced loss of lives (medium confidence), but hard defences

against flooding or sea level rise can also be maladaptive

(high conﬁdence). {WGII SPM C.2.1, WGII SPM C.4.1, WGII SPM C.4.2,

WGII SPM C.2.5}

Protection and restoration of coastal ‘blue carbon’ ecosystems

(e.g., mangroves, tidal marshes and seagrass meadows) could

reduce emissions and/or increase carbon uptake and storage (medium

conﬁdence). Coastal wetlands protect against coastal erosion

and ﬂooding (very high conﬁdence). Strengthening precautionary

approaches, such as rebuilding overexploited or depleted ﬁsheries, and

responsiveness of existing ﬁsheries management strategies reduces

negative climate change impacts on ﬁsheries, with beneﬁts for regional

economies and livelihoods (medium conﬁdence). Ecosystem-based

management in fisheries and aquaculture supports food security,

biodiversity, human health and well-being (high confidence).

{WGII SPM C.2.2, WGII SPM C.2; SROCC SPM C2.3, SROCC SPM C.2.4}

4.5.5. Health and Nutrition

Human health will beneﬁt from integrated mitigation and

adaptation options that mainstream health into food,

infrastructure, social protection, and water policies (very high

conﬁdence). Balanced and sustainable healthy diets

156

and reduced

food loss and waste present important opportunities for adaptation

and mitigation while generating signiﬁcant co-beneﬁts in terms

of biodiversity and human health (high conﬁdence). Public health

policies to improve nutrition, such as increasing the diversity of food

sources in public procurement, health insurance, ﬁnancial incentives,

and awareness-raising campaigns, can potentially influence food

demand, reduce food waste, reduce healthcare costs, contribute to

lower GHG emissions and enhance adaptive capacity (high conﬁdence).

107

Near-Term Responses in a Changing Climate

Section 4

Improved access to clean energy sources and technologies, and shifts

to active mobility (e.g., walking and cycling) and public transport can

deliver socioeconomic, air quality and health benefits, especially

for women and children (high confidence). {WGII SPM C.2.2, WGII

SPM C.2.11, WGII Cross-Chapter Box HEALTH; WGIII SPM C.2.2,

WGIII SPM C.4.2, WGIII SPM C.9.1, WGIII SPM C.10.4, WGIII SPM

D.1.3, WGIII Figure SPM.6, WGIII Figure SPM.8; SRCCL SPM B.6.2,

SRCCL SPM B.6.3, SRCCL B.4.6, SRCCL SPM C.2.4}

Effective adaptation options exist to help protect human health

and well-being (high conﬁdence). Health Action Plans that include

early warning and response systems are effective for extreme heat (high

conﬁdence). Effective options for water-borne and food-borne diseases

include improving access to potable water, reducing exposure of water and

sanitation systems to ﬂooding and extreme weather events, and improved

early warning systems (very high conﬁdence). For vector-borne diseases,

effective adaptation options include surveillance, early warning

systems, and vaccine development (very high conﬁdence). Effective

adaptation options for reducing mental health risks under climate

change include improving surveillance and access to mental health

care, and monitoring of psychosocial impacts from extreme weather

events (high conﬁdence). A key pathway to climate resilience in the

health sector is universal access to healthcare (high conﬁdence).

{WGII SPM C.2.11, WGII 7.4.6}

4.5.6 Society, Livelihoods, and Economies

Enhancing knowledge on risks and available adaptation options

promotes societal responses, and behaviour and lifestyle changes

supported by policies, infrastructure and technology can help

reduce global GHG emissions (high conﬁdence). Climate literacy

and information provided through climate services and community

approaches, including those that are informed by Indigenous Knowledge

and local knowledge, can accelerate behavioural changes and planning

(high conﬁdence). Educational and information programmes, using

the arts, participatory modelling and citizen science can facilitate

awareness, heighten risk perception, and inﬂuence behaviours (high

conﬁdence). The way choices are presented can enable adoption of low

GHG intensive socio-cultural options, such as shifts to balanced, sustainable

healthy diets, reduced food waste, and active mobility (high conﬁdence).

Judicious labelling, framing, and communication of social norms can

increase the effect of mandates, subsidies, or taxes (medium conﬁdence).

{WGII SPM C.5.3, WGII TS.D.10.1; WGIII SPM C.10, WGIII SPM C.10.2,

WGIII SPM C.10.3, WGIII SPM E.2.2, WGIII Figure SPM.6, WGIII TS.6.1,

5.4; SR1.5 SPM D.5.6; SROCC SPM C.4}

A range of adaptation options, such as disaster risk management,

early warning systems, climate services and risk spreading and

sharing approaches, have broad applicability across sectors

and provide greater risk reduction beneﬁts when combined

(high conﬁdence). Climate services that are demand-driven and

inclusive of different users and providers can improve agricultural

practices, inform better water use and efﬁciency, and enable resilient

infrastructure planning (high conﬁdence). Policy mixes that include

weather and health insurance, social protection and adaptive safety

nets, contingent ﬁnance and reserve funds, and universal access to

early warning systems combined with effective contingency plans, can

reduce vulnerability and exposure of human systems (high conﬁdence).

Integrating climate adaptation into social protection programs,

including cash transfers and public works programs, is highly feasible

and increases resilience to climate change, especially when supported

by basic services and infrastructure (high conﬁdence). Social safety nets

can build adaptive capacities, reduce socioeconomic vulnerability, and

reduce risk linked to hazards (robust evidence, medium agreement).

{WGII SPM C.2.9, WGII SPM C.2.13, WGII Cross-Chapter Box FEASIB in

Chapter 18; SRCCL SPM C.1.4, SRCCL SPM D.1.2}

Reducing future risks of involuntary migration and displacement

due to climate change is possible through cooperative, international

efforts to enhance institutional adaptive capacity and sustainable

development (high conﬁdence). Increasing adaptive capacity minimises

risk associated with involuntary migration and immobility and improves

the degree of choice under which migration decisions are made, while

policy interventions can remove barriers and expand the alternatives for

safe, orderly and regular migration that allows vulnerable people to adapt

to climate change (high conﬁdence). {WGII SPM C.2.12, WGII TS.D.8.6,

WGII Cross-Chapter Box MIGRATE in Chapter 7}

Accelerating commitment and follow-through by the private

sector is promoted for instance by building business cases for

adaptation, accountability and transparency mechanisms, and

monitoring and evaluation of adaptation progress (medium

conﬁdence). Integrated pathways for managing climate risks will

be most suitable when so-called ‘low-regret’ anticipatory options are

established jointly across sectors in a timely manner and are feasible

and effective in their local context, and when path dependencies and

maladaptations across sectors are avoided (high conﬁdence). Sustained

adaptation actions are strengthened by mainstreaming adaptation into

institutional budget and policy planning cycles, statutory planning,

monitoring and evaluation frameworks and into recovery efforts

from disaster events (high conﬁdence). Instruments that incorporate

adaptation such as policy and legal frameworks, behavioural incentives,

and economic instruments that address market failures, such as

climate risk disclosure, inclusive and deliberative processes strengthen

adaptation actions by public and private actors (medium conﬁdence).

{WGII SPM C.5.1, WGII SPM C.5.2, WGII TS.D.10.4}

108

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Section 1

Section 4

Many mitigation and adaptation actions have multiple synergies

with Sustainable Development Goals (SDGs), but some actions

can also have trade-offs. Potential synergies with SDGs exceed

potential trade-offs. Synergies and trade-offs are context specific

and depend on: means and scale of implementation, intra- and

inter-sectoral interactions, cooperation between countries and regions,

the sequencing, timing and stringency of actions, governance, and

policy design. Eradicating extreme poverty, energy poverty, and

providing decent living standards to all, consistent with near-

term sustainable development objectives, can be achieved

without significant global emissions growth. (high confidence)

{WGII SPM C.2.3, WGII Figure SPM.4b; WGIII SPM B.3.3, WGIII SPM C.9.2,

WGIII SPM D.1.2, WGIII SPM D.1.4, WGIII Figure SPM.8} (Figure 4.5)

Several mitigation and adaptation options can harness near-

term synergies and reduce trade-offs to advance sustainable

development in energy, urban and land systems (Figure 4.5)

(high conﬁdence). Clean energy supply systems have multiple

co-benefits, including improvements in air quality and health.

Heat Health Action Plans that include early warning and response

systems, approaches that mainstream health into food, livelihoods,

social protection, water and sanitation benefit health and well-

being. There are potential synergies between multiple Sustainable

Development Goals and sustainable land use and urban planning

with more green spaces, reduced air pollution, and demand-side

mitigation including shifts to balanced, sustainable healthy diets.

Electriﬁcation combined with low-GHG energy, and shifts to public

transport can enhance health, employment, and can contribute to

energy security and deliver equity. Conservation, protection and

restoration of terrestrial, freshwater, coastal and ocean ecosystems,

together with targeted management to adapt to unavoidable impacts

of climate change can generate multiple additional beneﬁts, such as

agricultural productivity, food security, and biodiversity conservation.

(high confidence) {WGII SPM C.1.1, WGII C.2.4, WGII SPM D.1,

WGII Figure SPM.4, WGII Cross-Chapter Box HEALTH in Chapter 17,

WGII Cross-Chapter Box FEASIB in Chapter 18; WGIII SPM C.4.2,

WGIII SPM D.1.3, WGIII SPM D.2, WGIII Figure SPM.8; SRCCL SPM B.4.6}

When implementing mitigation and adaptation together, and

taking trade-offs into account, multiple co-beneﬁts and synergies

for human well-being as well as ecosystem and planetary health

can be realised (high conﬁdence). There is a strong link between

sustainable development, vulnerability and climate risks. Social safety

nets that support climate change adaptation have strong co-beneﬁts

with development goals such as education, poverty alleviation, gender

inclusion and food security. Land restoration contributes to mitigation

and adaptation with synergies via enhanced ecosystem services and

with economically positive returns and co-beneﬁts for poverty reduction

and improved livelihoods. Trade-offs can be evaluated and minimised

by giving emphasis to capacity building, ﬁnance, technology transfer,

investments; governance, development, context speciﬁc gender-based

and other social equity considerations with meaningful participation

of Indigenous Peoples, local communities and vulnerable populations.

(high conﬁdence). {WGII SPM C.2.9, WGII SPM C.5.6, WGII SPM D.5.2,

WGII Cross-Chapter Box on Gender in Chapter 18; WGIII SPM C.9.2,

WGIII SPM D.1.2, WGIII SPM D.1.4, WGIII SPM D.2; SRCCL SPM D.2.2, SRCCL TS.4}

Context relevant design and implementation requires

considering people’s needs, biodiversity, and other sustainable

development dimensions (very high conﬁdence). Countries at

all stages of economic development seek to improve the well-being

of people, and their development priorities reﬂect different starting

points and contexts. Different contexts include but are not limited to

social, economic, environmental, cultural, or political circumstances,

resource endowment, capabilities, international environment, and prior

development. n regions with high dependency on fossil fuels for, among

other things, revenue and employment generation, mitigating risks for

sustainable development requires policies that promote economic and

energy sector diversiﬁcation and considerations of just transitions

principles, processes and practices (high conﬁdence). For individuals and

households in low-lying coastal areas, in Small Islands, and smallholder

farmers transitioning from incremental to transformational adaptation

can help overcome soft adaptation limits (high conﬁdence). Effective

governance is needed to limit trade-offs of some mitigation options

such as large scale afforestation and bioenergy options due to risks

from their deployment for food systems, biodiversity, other ecosystem

functions and services, and livelihoods (high conﬁdence). Effective

governance requires adequate institutional capacity at all levels

(high confidence). {WGII SPM B.5.4, WGII SPM C.3.1, WGII SPM

C.3.4; WGIII SPM D.1.3, WGIII SPM E.4.2; SR1.5 SPM C.3.4,

SR1.5 SPM C.3.5, SR1.5 SPM Figure SPM.4, SR1.5 SPM D.4.3,

SR1.5 SPM D.4.4}

4.6 Co-Beneﬁts of Adaptation and Mitigation for Sustainable Development Goals

Mitigation and adaptation actions have more synergies than trade-offs with Sustainable Development Goals

(SDGs). Synergies and trade-offs depend on context and scale of implementation. Potential trade-offs can be

compensated or avoided with additional policies, investments and ﬁnancial partnerships. (high conﬁdence)

109

Near-Term Responses in a Changing Climate

Section 4

Near-term adaptation and mitigation actions have more synergies

than trade-offs with Sustainable Development Goals (SDGs)

Synergies and trade-offs depend on context and scale

Energy systems

SDGs

Urban and infrastructure Land system

Ocean

ecosystems

Society,

livelihoods, and

economies

Industry

AdaptationMitigation AdaptationMitigation AdaptationMitigation Adaptation Adaptation Mitigation

Limited evidence/no evidence/no assessment

Both synergies and trade-offs/mixed

Trade-offs

Synergies

Key

Figure 4.5: Potential synergies and trade-offs between the portfolio of climate change mitigation and adaptation options and the Sustainable Development

Goals (SDGs). This ﬁgure presents a high-level summary of potential synergies and trade-offs assessed in WGII Figure SPM.4b and WGIII Figure SPM.8, based on the qualitative and

quantitative assessment of each individual mitigation or option. The SDGs serve as an analytical framework for the assessment of different sustainable development dimensions, which

extend beyond the time frame of 2030 SDG targets. Synergies and trade-offs across all individual options within a sector/system are aggregated into sector/system potentials for the

whole mitigation or adaptation portfolio. The length of each bar represents the total number of mitigation or adaptation options under each system/sector. The number of adaptation

and mitigation options vary across system/sector, and have been normalised to 100% so that bars are comparable across mitigation, adaptation, system/sector, and SDGs. Positive

links shown in WGII Figure SPM.4b and WGIII Figure SPM.8 are counted and aggregated to generate the percentage share of synergies, represented here by the blue proportion

within the bars. Negative links shown in WGII Figure SPM.4b and WGIII Figure SPM.8 are counted and aggregated to generate the percentage share of trade-offs and is represented

by orange proportion within the bars. ‘Both synergies and trade-offs’ shown in WGII Figure SPM.4b WGIII Figure SPM.8 are counted and aggregated to generate the percentage share

of ‘both synergies and trade-off’, represented by the striped proportion within the bars. The ‘white’ proportion within the bar indicates limited evidence/ no evidence/ not assessed.

Energy systems comprise all mitigation options listed in WGIII Figure SPM.8 and WGII Figure SPM.4b for adaptation. Urban and infrastructure comprises all mitigation options listed

110

Section 4

Section 1

Section 4

in WGIII Figure SPM.8 under Urban systems, under Buildings and under Transport and adaptation options listed in WGII Figure SPM.4b under Urban and infrastructure systems. Land

system comprises mitigation options listed in WGIII Figure SPM.8 under AFOLU and adaptation options listed in WGII Figure SPM.4b under Land and ocean systems: forest-based

adaptation, agroforestry, biodiversity management and ecosystem connectivity, improved cropland management, efﬁcient livestock management, water use efﬁciency and water

resource management. Ocean ecosystems comprises adaptation options listed in WGII Figure SPM.4b under Land and ocean systems: coastal defence and hardening, integrated

coastal zone management and sustainable aquaculture and ﬁsheries. Society, livelihood and economies comprises adaptation options listed in WGII Figure SPM.4b under Cross-

sectoral; Industry comprises all those mitigation options listed in WGIII Figure SPM.8 under Industry. SDG 13 (Climate Action) is not listed because mitigation/ adaptation is being

considered in terms of interaction with SDGs and not vice versa (SPM SR1.5 Figure SPM.4 caption). The bars denote the strength of the connection and do not consider the strength

of the impact on the SDGs. The synergies and trade-offs differ depending on the context and the scale of implementation. Scale of implementation particularly matters when there is

competition for scarce resources. For the sake of uniformity, we are not reporting the conﬁdence levels because there is knowledge gap in adaptation option wise relation with SDGs

and their conﬁdence level which is evident from WGII ﬁg SPM.4b. {WGII Figure SPM.4b; WGIII Figure SPM.8}

Effective climate governance enables mitigation and adaptation

by providing overall direction based on national circumstances,

setting targets and priorities, mainstreaming climate action across

policy domains and levels, based on national circumstances and

in the context of international cooperation. Effective governance

enhances monitoring and evaluation and regulatory certainty,

prioritising inclusive, transparent and equitable decision-making,

and improves access to ﬁnance and technology (high conﬁdence).

These functions can be promoted by climate-relevant laws and

plans, which are growing in number across sectors and regions,

advancing mitigation outcomes and adaptation benefits (high

confidence). Climate laws have been growing in number and

have helped deliver mitigation and adaptation outcomes (medium

conﬁdence). {WGII SPM C.5, WGII SPM C.5.1, WGII SPM C5.4, WGII SPM C.5.6;

WGIII SPM B.5.2, WGIII SPM E.3.1}

Effective municipal, national and sub-national climate

institutions, such as expert and co-ordinating bodies, enable

co-produced, multi-scale decision-processes, build consensus

for action among diverse interests, and inform strategy settings

(high conﬁdence). This requires adequate institutional capacity at

all levels (high conﬁdence). Vulnerabilities and climate risks are often

reduced through carefully designed and implemented laws, policies,

participatory processes, and interventions that address context

speciﬁc inequities such as based on gender, ethnicity, disability, age,

location and income (high conﬁdence). Policy support is inﬂuenced by

Indigenous Peoples, businesses, and actors in civil society, including,

youth, labour, media, and local communities, and effectiveness is

enhanced by partnerships between many different groups in society

(high conﬁdence). Climate-related litigation is growing, with a large

number of cases in some developed countries and with a much smaller

number in some developing countries, and in some cases has inﬂuenced

the outcome and ambition of climate governance (medium conﬁdence).

{WGII SPM C2.6, WGII SPM C.5.2, WGII SPM C.5.5, WGII SPM C.5.6,

WGII SPM D.3.1; WGIII SPM E3.2, WGIII SPM E.3.3}

Effective climate governance is enabled by inclusive decision

processes, allocation of appropriate resources, and institutional

review, monitoring and evaluation (high conﬁdence). Multi-level,

hybrid and cross-sector governance facilitates appropriate consideration

for co-beneﬁts and trade-offs, particularly in land sectors where decision

processes range from farm level to national scale (high conﬁdence).

Consideration of climate justice can help to facilitate shifting development

pathways towards sustainability. {WGII SPM C.5.5, WGII SPM C.5.6,

WGII SPM D.1.1, WGII SPM D.2, WGII SPM D.3.2; SRCCL SPM C.3,

SRCCL TS.1}

Drawing on diverse knowledge and partnerships, including

with women, youth, Indigenous Peoples, local communities, and

ethnic minorities can facilitate climate resilient development

and has allowed locally appropriate and socially acceptable

solutions (high conﬁdence). {WGII SPM D.2, D.2.1}

Many regulatory and economic instruments have already been

deployed successfully. These instruments could support deep

emissions reductions if scaled up and applied more widely.

Practical experience has informed instrument design and helped to

improve predictability, environmental effectiveness, economic efﬁciency,

and equity. (high conﬁdence) {WGII SPM E.4; WGIII SPM E.4.2}

Scaling up and enhancing the use of regulatory instruments,

consistent with national circumstances, can improve mitigation

outcomes in sectoral applications (high conﬁdence), and

regulatory instruments that include ﬂexibility mechanisms

can reduce costs of cutting emissions (medium conﬁdence).

{WGII SPM C.5.4; WGIII SPM E.4.1}

Where implemented, carbon pricing instruments have incentivized

low-cost emissions reduction measures, but have been less

effective, on their own and at prevailing prices during the

assessment period, to promote higher-cost measures necessary

for further reductions (medium conﬁdence). Revenue from carbon

taxes or emissions trading can be used for equity and distributional

goals, for example to support low-income households, among other

4.7 Governance and Policy for Near-Term Climate Change Action

Effective climate action requires political commitment, well-aligned multi-level governance and institutional

frameworks, laws, policies and strategies. It needs clear goals, adequate ﬁnance and ﬁnancing tools, coordination

across multiple policy domains, and inclusive governance processes. Many mitigation and adaptation policy

instruments have been deployed successfully, and could support deep emissions reductions and climate resilience

if scaled up and applied widely, depending on national circumstances. Adaptation and mitigation action beneﬁts

from drawing on diverse knowledge. (high conﬁdence)

111

Near-Term Responses in a Changing Climate

Section 4

4.8.1. Finance for Mitigation and Adaptation Actions

Improved availability and access to ﬁnance

157

will enable

accelerated climate action (very high conﬁdence). Addressing

needs and gaps and broadening equitable access to domestic and

international ﬁnance, when combined with other supportive actions, can

act as a catalyst for accelerating mitigation and shifting development

pathways (high conﬁdence). Climate resilient development is enabled

by increased international cooperation including improved access

to ﬁnancial resources, particularly for vulnerable regions, sectors

and groups, and inclusive governance and coordinated policies (high

conﬁdence). Accelerated international ﬁnancial cooperation is a critical

enabler of low-GHG and just transitions, and can address inequities in

access to ﬁnance and the costs of, and vulnerability to, the impacts of

climate change (high conﬁdence). {WGII SPM C.1.2, WGII SPM C.3.2,

WGII SPM C.5, WGII SPM C.5.4, WGII SPM D.2, WGII SPM D.3.2,

WGII SPM D.5, WGII SPM D.5.2; WGIII SPM B.4.2,WGIII SPM B.5,

WGIII SPM B.5.4, WGIII SPM C.4.2, WGIII SPM C.7.3, WGIII SPM C.8.5,

WGIII SPM D.1.2, WGIII SPM D.2.4, WGIII SPM D.3.4, WGIII SPM E.2.3,

WGIII SPM E.3.1, WGIII SPM E.5, WGIII SPM E.5.1, WGIII SPM E.5.2,

WGIII SPM E.5.3, WGIII SPM E.5.4, WGIII SPM E.6.2}

Both adaptation and mitigation ﬁnance need to increase many-fold,

to address rising climate risks and to accelerate investments in

emissions reduction (high conﬁdence). Increased ﬁnance would

address soft limits to adaptation and rising climate risks while also averting

157

Finance can originate from diverse sources, singly or in combination: public or private, local, national or international, bilateral or multilateral, and alternative sources

(e.g., philanthropic, carbon offsets). It can be in the form of grants, technical assistance, loans (concessional and non-concessional), bonds, equity, risk insurance and ﬁnancial

guarantees (of various types).

some related losses and damages, particularly in vulnerable developing

countries (high conﬁdence). Enhanced mobilisation of and access to

ﬁnance, together with building capacity, are essential for implementation

of adaptation actions and to reduce adaptation gaps given rising risks

and costs, especially for the most vulnerable groups, regions and sectors

(high conﬁdence). Public ﬁnance is an important enabler of adaptation

and mitigation, and can also leverage private ﬁnance (high conﬁdence).

Adaptation funding predominately comes from public sources, and

public mechanisms and ﬁnance can leverage private sector ﬁnance by

addressing real and perceived regulatory, cost and market barriers, for

instance via public-private partnerships (high conﬁdence). Financial and

technological resources enable effective and ongoing implementation

of adaptation, especially when supported by institutions with a strong

understanding of adaptation needs and capacity (high conﬁdence).

Average annual modelled mitigation investment requirements for

2020 to 2030 in scenarios that limit warming to 2°C or 1.5°C are a

factor of three to six greater than current levels, and total mitigation

investments (public, private, domestic and international) would need

to increase across all sectors and regions (medium conﬁdence). Even

if extensive global mitigation efforts are implemented, there will be a

large need for ﬁnancial, technical, and human resources for adaptation

(high conﬁdence). {WGII SPM C.1.2, WGII SPM C2.11, WGII SPM C.3,

WGII SPM C.3.2, WGII SPM C3.5, WGII SPM C.5, WGII SPM C.5.4,

WGII SPM D.1, WGII SPM D.1.1, WGII SPM D.1.2, WGII SPM C.5.4;

WGIII SPM D.2.4, WGIII SPM E.5, WGIII SPM E.5.1, WGIII 15.2}

(Section 2.3.2, 2.3.3, 4.4, Figure 4.6)

approaches (high conﬁdence). There is no consistent evidence that

current emission trading systems have led to signiﬁcant emissions

leakage (medium conﬁdence). {WGIII SPM E4.2, WGIII SPM E.4.6}

Removing fossil fuel subsidies would reduce emissions, improve

public revenue and macroeconomic performance, and yield

other environmental and sustainable development beneﬁts such

as improved public revenue, macroeconomic and sustainability

performance; subsidy removal can have adverse distributional

impacts especially on the most economically vulnerable

groups which, in some cases, can be mitigated by measures

such as re-distributing revenue saved, and depend on national

circumstances (high conﬁdence). Fossil fuel subsidy removal is

projected by various studies to reduce global CO

emissions by 1–4%,

and GHG emissions by up to 10% by 2030, varying across regions

(medium conﬁdence). {WGIII SPM E.4.2}

National policies to support technology development, and

participation in international markets for emission reduction,

can bring positive spillover effects for other countries

(medium conﬁdence), although reduced demand for fossil fuels as

a result of climate policy could result in costs to exporting countries

(high confidence). Economy-wide packages can meet short-term

economic goals while reducing emissions and shifting development

pathways towards sustainability (medium confidence). Examples

are public spending commitments; pricing reforms; and investment

in education and training, R&D and infrastructure (high confidence).

Effective policy packages would be comprehensive in coverage,

harnessed to a clear vision for change, balanced across objectives,

aligned with specific technology and system needs, consistent

in terms of design and tailored to national circumstances (high

confidence). {WGIII SPM E4.4, WGIII SPM 4.5, WGIII SPM 4.6}

4.8 Strengthening the Response: Finance, International Cooperation and Technology

Finance, international cooperation and technology are critical enablers for accelerated climate action. If climate

goals are to be achieved, both adaptation and mitigation ﬁnancing would have to increase many-fold. There is

sufﬁcient global capital to close the global investment gaps but there are barriers to redirect capital to climate

action. Barriers include institutional, regulatory and market access barriers, which can be reduced to address the

needs and opportunities, economic vulnerability and indebtedness in many developing countries. Enhancing

international cooperation is possible through multiple channels. Enhancing technology innovation systems is

key to accelerate the widespread adoption of technologies and practices. (high conﬁdence)

112

Section 4

Section 1

Section 4

There is sufﬁcient global capital and liquidity to close global

investment gaps, given the size of the global ﬁnancial system,

but there are barriers to redirect capital to climate action

both within and outside the global ﬁnancial sector and in the

context of economic vulnerabilities and indebtedness facing

many developing countries (high conﬁdence). For shifts in private

finance, options include better assessment of climate-related risks

and investment opportunities within the financial system, reducing

sectoral and regional mismatches between available capital and

investment needs, improving the risk-return profiles of climate

investments, and developing institutional capacities and local

capital markets. Macroeconomic barriers include, amongst others,

indebtedness and economic vulnerability of developing regions.

(high conﬁdence) {WGII SPM C.5.4; WGIII SPM E.4.2, WGIII SPM E.5,

WGIII SPM E.5.2, WGIII SPM E.5.3}

Scaling up ﬁnancial ﬂows requires clear signalling from

governments and the international community (high conﬁdence).

Tracked ﬁnancial ﬂows fall short of the levels needed for

adaptation and to achieve mitigation goals across all sectors and

regions (high conﬁdence). These gaps create many opportunities

and the challenge of closing gaps is largest in developing

countries (high conﬁdence). This includes a stronger alignment of

public ﬁnance, lowering real and perceived regulatory, cost and market

barriers, and higher levels of public ﬁnance to lower the risks associated

with low-emission investments. Up-front risks deter economically

sound low carbon projects, and developing local capital markets are an

option. Investors, ﬁnancial intermediaries, central banks and ﬁnancial

regulators can shift the systemic underpricing of climate-related risks. A

robust labelling of bonds and transparency is needed to attract savers.

(high conﬁdence) {WGII SPM C.5.4; WGIII SPM B.5.4, WGIII SPM E.4,

WGIII SPM E.5.4, WGIII 15.2, WGIII 15.6.1, WGIII 15.6.2, WGIII 15.6.7}

The largest climate ﬁnance gaps and opportunities are in

developing countries (high conﬁdence). Accelerated support

from developed countries and multilateral institutions is a critical

enabler to enhance mitigation and adaptation action and can address

inequities in ﬁnance, including its costs, terms and conditions, and

economic vulnerability to climate change. Scaled-up public grants for

mitigation and adaptation funding for vulnerable regions, e.g., in Sub-

Saharan Africa, would be cost-effective and have high social returns

in terms of access to basic energy. Options for scaling up mitigation

and adaptation in developing regions include: increased levels of public

ﬁnance and publicly mobilised private ﬁnance ﬂows from developed

to developing countries in the context of the USD 100 billion-a-year

goal of the Paris Agreement; increase the use of public guarantees

to reduce risks and leverage private ﬂows at lower cost; local capital

markets development; and building greater trust in international

cooperation processes. A coordinated effort to make the post-

pandemic recovery sustainable over the long term through increased

ﬂows of ﬁnancing over this decade can accelerate climate action,

including in developing regions facing high debt costs, debt distress

and macroeconomic uncertainty. (high conﬁdence) {WGII SPM C.5.2,

WGII SPM C.5.4, WGII SPM C.6.5, WGII SPM D.2, WGII TS.D.10.2;

WGIII SPM E.5, WGIII SPM E.5.3, WGIII TS.6.4, WGIII Box TS.1, WGIII 15.2,

WGIII 15.6}

4.8.2. International Cooperation and Coordination

International cooperation is a critical enabler for achieving

ambitious climate change mitigation goals and climate resilient

development (high conﬁdence). Climate resilient development is

enabled by increased international cooperation including mobilising

and enhancing access to ﬁnance, particularly for developing countries,

vulnerable regions, sectors and groups and aligning ﬁnance ﬂows

for climate action to be consistent with ambition levels and funding

needs (high conﬁdence). While agreed processes and goals, such as

those in the UNFCCC, Kyoto Protocol and Paris Agreement, are helping

(Section 2.2.1), international ﬁnancial, technology and capacity building

support to developing countries will enable greater implementation

and more ambitious actions (medium conﬁdence). By integrating

equity and climate justice, national and international policies can help

to facilitate shifting development pathways towards sustainability,

especially by mobilising and enhancing access to ﬁnance for vulnerable

regions, sectors and communities (high conﬁdence). International

cooperation and coordination, including combined policy packages,

may be particularly important for sustainability transitions in emissions-

intensive and highly traded basic materials industries that are exposed

to international competition (high conﬁdence). The large majority of

emission modelling studies assume signiﬁcant international cooperation

to secure ﬁnancial ﬂows and address inequality and poverty issues in

pathways limiting global warming. There are large variations in the

modelled effects of mitigation on GDP across regions, depending

notably on economic structure, regional emissions reductions, policy

design and level of international cooperation (high confidence).

Delayed global cooperation increases policy costs across regions

(high confidence). {WGII SPM D.2, WGII SPM D.3.1, WGII SPM D.5.2;

WGIII SPM D.3.4, WGIII SPM C5.4, WGIII SPM C.12.2, WGIII SPM E.6,

WGIII SPM E.6.1, WGIII E.5.4, WGIII TS.4.2, WGIII TS.6.2; SR1.5 SPM D.6.3,

SR1.5 SPM D.7, SR1.5 SPM D.7.3}

The transboundary nature of many climate change risks (e.g., for

supply chains, markets and natural resource ﬂows in food, ﬁsheries,

energy and water, and potential for conﬂict) increases the need

for climate-informed transboundary management, cooperation,

responses and solutions through multi-national or regional

governance processes (high conﬁdence). Multilateral governance

efforts can help reconcile contested interests, world views and values

about how to address climate change. International environment and

sectoral agreements, and initiatives in some cases, may help to stimulate

low GHG investment and reduce emissions (such as ozone depletion,

transboundary air pollution and atmospheric emissions of mercury).

Improvements to national and international governance structures

would further enable the decarbonisation of shipping and aviation

through deployment of low-emissions fuels, for example through

stricter efficiency and carbon intensity standards. Transnational

partnerships can also stimulate policy development, low-emissions

technology diffusion, emission reductions and adaptation, by linking sub-

national and other actors, including cities, regions, non-governmental

organisations and private sector entities, and by enhancing interactions

between state and non-state actors, though uncertainties remain over

their costs, feasibility, and effectiveness. International environmental

and sectoral agreements, institutions, and initiatives are helping, and

in some cases may help, to stimulate low GHG emissions investment

and reduce emissions. (medium conﬁdence) {WGII SPM B.5.3, WGII SPM

C.5.6, WGII TS.E.5.4, WGII TS.E.5.5; WGIII SPM C.8.4, WGIII SPM E.6.3,

WGIII SPM E.6.4, WGIII SPM E.6.4, WGIII TS.5.3}

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Near-Term Responses in a Changing Climate

Section 4

4.8.3. Technology Innovation, Adoption, Diffusion and

Transfer

Enhancing technology innovation systems can provide

opportunities to lower emissions growth and create social and

environmental co-beneﬁts. Policy packages tailored to national

contexts and technological characteristics have been effective

in supporting low-emission innovation and technology diffusion.

Support for successful low-carbon technological innovation

includes public policies such as training and R&D, complemented by

regulatory and market-based instruments that create incentives and

market opportunities such as appliance performance standards and

building codes. (high confidence) {WGIII SPM B.4, WGIII SPM B.4.4,

WGIII SPM E.4.3, WGIII SPM E4.4}

International cooperation on innovation systems and technology

development and transfer, accompanied by capacity building,

knowledge sharing, and technical and ﬁnancial support can

accelerate the global diffusion of mitigation technologies,

practices and policies and align these with other development

objectives (high conﬁdence). Choice architecture can help end-users

adopt technology and low-GHG-intensive options (high conﬁdence).

Adoption of low-emission technologies lags in most developing countries,

particularly least developed ones, due in part to weaker enabling

conditions, including limited ﬁnance, technology development and

transfer, and capacity building (medium conﬁdence). {WGIII SPM B.4.2,

WGIII SPM E.6.2, WGIII SPM C.10.4, WGIII 16.5}

Higher mitigation investment ﬂows required for

all sectors and regions to limit global warming

Actual yearly ﬂows compared to average annual needs

in billions USD (2015) per year

Multiplication

factors*

0 1000 1500 2000 2500 3000500

2017

2018

2019

2020

Annual mitigation investment

needs (averaged until 2030)

IEA data mean

2017–2020

Average ﬂows

0 1000 1500 2000 2500 3000500

*Multiplication factors indicate the x-fold increase between yearly

mitigation ﬂows to average yearly mitigation investment needs.

Globally, current mitigation ﬁnancial ﬂows are a factor of three

to six below the average levels up to 2030.

Yearly mitigation investment

ﬂows (USD 2015/yr ) in:

By sector

By type of economy

Energy efﬁciency

Developing countries

By region

Europe

Eastern Europe and West-Central Asia

Latin America and Caribbean

Africa

Middle East

North America

Australia, Japan and New Zealand

South-East Asia and Paciﬁc

Southern Asia

Developed countries

Agriculture, forestry and other land use

Electricity

Transport

Eastern Asia

Lower

range

Upper

range

x10 x31

x2 x5

x7 x14

x12

x14 x28

x12

x3 x6

x7 x15

x4 x7

x7 x7

x2 x4

Figure 4.6: Breakdown of average mitigation investment ﬂows and investment needs until 2030 (USD billion). Mitigation investment ﬂows and investment needs by

sector (energy efﬁciency, transport, electricity, and agriculture, forestry and other land use), by type of economy, and by region (see WGIII Annex II Part I Section 1 for the classiﬁcation

schemes for countries and areas). The blue bars display data on mitigation investment ﬂows for four years: 2017, 2018, 2019 and 2020 by sector and by type of economy. For the

regional breakdown, the annual average mitigation investment ﬂows for 2017–2019 are shown. The grey bars show the minimum and maximum level of global annual mitigation

investment needs in the assessed scenarios. This has been averaged until 2030. The multiplication factors show the ratio of global average early mitigation investment needs

(averaged until 2030) and current yearly mitigation ﬂows (averaged for 2017/18–2020). The lower multiplication factor refers to the lower end of the range of investment needs.

The upper multiplication factor refers to the upper range of investment needs. Given the multiple sources and lack of harmonised methodologies, the data can be considered only if

indicative of the size and pattern of investment needs. {WGIII Figure TS.25, WGIII 15.3, WGIII 15.4, WGIII 15.5, WGIII Table 15.2, WGIII Table 15.3, WGIII Table 15.4}

114

Section 4

Section 1

Section 4

International cooperation on innovation works best when tailored to

and beneﬁcial for local value chains, when partners collaborate on an

equal footing, and when capacity building is an integral part of the

effort (medium conﬁdence). {WGIII SPM E.4.4, WGIII SPM E.6.2}

Technological innovation can have trade-offs that include

externalities such as new and greater environmental impacts and

social inequalities; rebound effects leading to lower net emission

reductions or even emission increases; and overdependence on

foreign knowledge and providers (high conﬁdence). Appropriately

designed policies and governance have helped address distributional

impacts and rebound effects (high conﬁdence). For example, digital

technologies can promote large increases in energy efﬁciency through

coordination and an economic shift to services (high conﬁdence).

However, societal digitalization can induce greater consumption of

goods and energy and increased electronic waste as well as negatively

impacting labour markets and worsening inequalities between

and within countries (medium conﬁdence). Digitalisation requires

appropriate governance and policies in order to enhance mitigation

potential (high conﬁdence). Effective policy packages can help to

realise synergies, avoid trade-offs and/or reduce rebound effects:

these might include a mix of efﬁciency targets, performance standards,

information provision, carbon pricing, ﬁnance and technical assistance

(high conﬁdence). {WGIII SPM B.4.2, WGIII SPM B.4.3, WGIII SPM E.4.4,

WGIII TS 6.5, WGIII Cross-Chapter Box 11 on Digitalization in Chapter 16}

Technology transfer to expand use of digital technologies for land use

monitoring, sustainable land management, and improved agricultural

productivity supports reduced emissions from deforestation and land

use change while also improving GHG accounting and standardisation

(medium conﬁdence). {SRCCL SPM C.2.1, SRCCL SPM D.1.2, SRCCL SPM D.1.4,

SRCCL 7.4.4, SRCCL 7.4.6}

Climate resilient development strategies that treat climate,

ecosystems and biodiversity, and human society as parts of an

integrated system are the most effective (high conﬁdence). Human

and ecosystem vulnerability are interdependent (high conﬁdence).

Climate resilient development is enabled when decision-making processes

and actions are integrated across sectors (very high conﬁdence).

Synergies with and progress towards the Sustainable Development

Goals enhance prospects for climate resilient development. Choices and

actions that treat humans and ecosystems as an integrated system build

on diverse knowledge about climate risk, equitable, just and inclusive

approaches, and ecosystem stewardship. {WGII SPM B.2, WGII Figure

SPM.5, WGII SPM D.2, WGII SPM D2.1, WGII SPM 2.2, WGII SPM D4,

WGII SPM D4.1, WGII SPM D4.2, WGII SPM D5.2, WGII Figure SPM.5}

Approaches that align goals and actions across sectors provide

opportunities for multiple and large-scale beneﬁts and avoided

damages in the near term. Such measures can also achieve

greater beneﬁts through cascading effects across sectors

(medium conﬁdence). For example, the feasibility of using land for

both agriculture and centralised solar production can increase when

such options are combined (high conﬁdence). Similarly, integrated

transport and energy infrastructure planning and operations can

together reduce the environmental, social, and economic impacts of

decarbonising the transport and energy sectors (high conﬁdence). The

implementation of packages of multiple city-scale mitigation strategies

can have cascading effects across sectors and reduce GHG emissions

both within and outside a city’s administrative boundaries (very high

conﬁdence). Integrated design approaches to the construction and

retroﬁt of buildings provide increasing examples of zero energy or

zero carbon buildings in several regions. To minimise maladaptation,

multi-sectoral, multi-actor and inclusive planning with ﬂexible

pathways encourages low-regret and timely actions that keep options

open, ensure beneﬁts in multiple sectors and systems and suggest the

available solution space for adapting to long-term climate change

(very high conﬁdence). Trade-offs in terms of employment, water

use, land-use competition and biodiversity, as well as access to,

and the affordability of, energy, food, and water can be avoided

by well-implemented land-based mitigation options, especially those

that do not threaten existing sustainable land uses and land rights, with

frameworks for integrated policy implementation (high conﬁdence).

{WGII SPM C.2, WGII SPM C.4.4; WGIII SPM C.6.3, WGIII SPM C.6,

WGIII SPM C.7.2, WGIII SPM C.8.5, WGIII SPM D.1.2, WGIII SPM D.1.5,

WGIII SPM E.1.2}

Mitigation and adaptation when implemented together, and

combined with broader sustainable development objectives,

would yield multiple beneﬁts for human well-being as well as

ecosystem and planetary health (high conﬁdence). The range of

such positive interactions is signiﬁcant in the landscape of near-term

climate policies across regions, sectors and systems. For example,

AFOLU mitigation actions in land-use change and forestry, when

sustainably implemented, can provide large-scale GHG emission

reductions and removals that simultaneously beneﬁt biodiversity, food

security, wood supply and other ecosystem services but cannot fully

compensate for delayed mitigation action in other sectors. Adaptation

measures in land, ocean and ecosystems similarly can have widespread

beneﬁts for food security, nutrition, health and well-being, ecosystems

and biodiversity. Equally, urban systems are critical, interconnected

sites for climate resilient development; urban policies that implement

multiple interventions can yield adaptation or mitigation gains with

equity and human well-being. Integrated policy packages can improve

the ability to integrate considerations of equity, gender equality

and justice. Coordinated cross-sectoral policies and planning can

maximise synergies and avoid or reduce trade-offs between mitigation

4.9 Integration of Near-Term Actions Across Sectors and Systems

The feasibility, effectiveness and beneﬁts of mitigation and adaptation actions are increased when multi-sectoral

solutions are undertaken that cut across systems. When such options are combined with broader sustainable

development objectives, they can yield greater beneﬁts for human well-being, social equity and justice, and

ecosystem and planetary health. (high conﬁdence)

115

Near-Term Responses in a Changing Climate

Section 4

and adaptation. Effective action in all of the above areas will

require near-term political commitment and follow-through, social

cooperation, ﬁnance, and more integrated cross-sectoral policies and

support and actions. (high conﬁdence). {WGII SPM C.1, WG II SPM C.2,

WGII SPM C.2, WGII SPM C.5, WGII SPM D.2, WGII SPM D.3.2,

WGII SPM D.3.3, WGII Figure SPM.4; WGIII SPM C.6.3, WGIII SPM C.8.2,

WGIII SPM C.9, WGIII SPM C.9.1, WGIII SPM C.9.2, WGIII SPM D.2,

WGIII SPM D.2.4, WGIII SPM D.3.2, WGIII SPM E.1, WGIII SPM E.2.4,

WGIII Figure SPM.8, WGIII TS.7, WGIII TS Figure TS.29: SRCCL ES 7.4.8,

SRCCL SPM B.6} (3.4, 4.4)

116

Annexes

119

Andy Reisinger (New Zealand), Diego Cammarano (Italy), Andreas Fischlin (Switzerland), Jan S. Fuglestvedt (Norway), Gerrit

Hansen (Germany), Yonghun Jung (Republic of Korea), Chloé Ludden (Germany/France), Valérie Masson-Delmotte (France), J.B.

Robin Matthews (France/United Kingdom), Katja Mintenbeck (Germany), Dan Jezreel Orendain (Philippines/Belgium), Anna Pirani

(Italy), Elvira Poloczanska (UK/Australia), José Romero (Switzerland)

Editorial Team

Annex I

Glossary

This Annex should be cited as: IPCC, 2023: Annex I: Glossary [Reisinger, A., D. Cammarano, A. Fischlin, J.S. Fuglestvedt, G.

Hansen, Y. Jung, C. Ludden, V. Masson-Delmotte, R. Matthews, J.B.K Mintenbeck, D.J. Orendain, A. Pirani, E. Poloczanska,

and J. Romero (eds.)]. In: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the

Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero

(eds.)]. IPCC, Geneva, Switzerland, pp. 119-130, doi:10.59327/IPCC/AR6-9789291691647.002.

120

Annex I

Annexes

This concise Synthesis Report (SYR) Glossary deﬁnes selected key

terms used in this report, drawn from the glossaries of the three

Working Group contributions to the AR6. A more comprehensive,

harmonised set of deﬁnitions for terms used in this SYR and the

three AR6 Working Group reports is available from the IPCC

Online Glossary: https://apps.ipcc.ch/glossary/

Readers are requested to refer to this comprehensive online

glossary for deﬁnitions of terms of a more technical nature, and

for scientiﬁc references relevant to individual terms. Italicized

words indicate that the term is deﬁned in this or/and the online

glossary. Subterms appear in italics beneath main terms.

2030 Agenda for Sustainable Development

A UN resolution in September 2015 aadopting a plan of action for

people, planet and prosperity in a new global development framework

anchored in 17 Sustainable Development Goals.

Abrupt climate change

A large-scale abrupt change in the climate system that takes place over

a few decades or less, persists (or is anticipated to persist) for at least

a few decades and causes substantial impacts in human and/or natural

systems. See also: Abrupt change, Tipping point.

Adaptation

In human systems, the process of adjustment to actual or expected

climate and its effects, in order to moderate harm or exploit beneﬁcial

opportunities. In natural systems, the process of adjustment to actual

climate and its effects; human intervention may facilitate adjustment

to expected climate and its effects. See also: Adaptation options,

Adaptive capacity, Maladaptive actions (Maladaptation).

Adaptation gap

The difference between actually implemented adaptation and a

societally set goal, determined largely by preferences related to

tolerated climate change impacts and reﬂecting resource limitations

and competing priorities.

Adaptation limits

The point at which an actor’s objectives (or system needs) cannot be

secured from intolerable risks through adaptive actions.

• Hard adaptation limit - No adaptive actions are possible to

avoid intolerable risks.

• Soft adaptation limit - Options may exist but are currently

not available to avoid intolerable risks through adaptive

action.

Transformational adaptation

Adaptation that changes the fundamental attributes of a

social-ecological system in anticipation of climate change and

its impacts.

Aerosol

A suspension of airborne solid or liquid particles, with typical particle

size in the range of a few nanometres to several tens of micrometres

and atmospheric lifetimes of up to several days in the troposphere

and up to years in the stratosphere. The term aerosol, which includes

both the particles and the suspending gas, is often used in this report

in its plural form to mean ‘aerosol particles’. Aerosols may be of either

natural or anthropogenic origin in the troposphere; stratospheric

aerosols mostly stem from volcanic eruptions. Aerosols can cause an

effective radiative forcing directly through scattering and absorbing

radiation (aerosol–radiation interaction), and indirectly by acting as

cloud condensation nuclei or ice nucleating particles that affect the

properties of clouds (aerosol–cloud interaction), and upon deposition

on snow- or ice-covered surfaces. Atmospheric aerosols may be either

emitted as primary particulate matter or formed within the atmosphere

from gaseous precursors (secondary production). Aerosols may be

composed of sea salt, organic carbon, black carbon (BC), mineral

species (mainly desert dust), sulphate, nitrate and ammonium or

their mixtures. See also: Particulate matter (PM), Aerosol–radiation

interaction, Short-lived climate forcers (SLCFs).

Afforestation

Conversion to forest of land that historically has not contained forests.

See also: Anthropogenic removals, Carbon dioxide removal (CDR),

Deforestation, Reducing Emissions from Deforestation and Forest

Degradation (REDD+), Reforestation.

[Note: For a discussion of the term forest and related terms such as

afforestation, reforestation and deforestation, see the 2006 IPCC

Guidelines for National Greenhouse Gas Inventories and their

2019 Refinement, and information provided by the United Nations

Framework Convention on Climate Change]

Agricultural drought

See: Drought.

Agriculture, Forestry and Other Land Use (AFOLU)

In the context of national greenhouse gas (GHG) inventories under

the United Nations Convention on Climate Change (UNFCCC),

AFOLU is the sum of the GHG inventory sectors Agriculture and

Land Use, Land-Use Change and Forestry (LULUCF); see the 2006

IPCC Guidelines for National GHG Inventories for details. Given the

difference in estimating the ‘anthropogenic’ carbon dioxide (CO

)

removals between countries and the global modelling community, the

land-related net GHG emissions from global models included in this

report are not necessarily directly comparable with LULUCF estimates

in national GHG Inventories. See also: Land use, land-use change and

forestry (LULUCF), Land-use change (LUC).

Agroforestry

Collective name for land-use systems and technologies where woody

perennials (trees, shrubs, palms, bamboos, etc.) are deliberately used

on the same land-management units as agricultural crops and/or

animals, in some form of spatial arrangement or temporal sequence.

In agroforestry systems there are both ecological and economical

interactions between the different components. Agroforestry can

also be deﬁned as a dynamic, ecologically based, natural resource

management system that, through the integration of trees on farms

121

Glossary

Annexes

and in the agricultural landscape, diversiﬁes and sustains production for

increased social, economic and environmental beneﬁts for land users at

all levels.

Anthropogenic

Resulting from or produced by human activities.

Behavioural change

In this report, behavioural change refers to alteration of human

decisions and actions in ways that mitigate climate change and/or

reduce negative consequences of climate change impacts.

Biodiversity

Biodiversity or biological diversity means the variability among living

organisms from all sources including, among other things, terrestrial,

marine and other aquatic ecosystems, and the ecological complexes

of which they are part; this includes diversity within species, between

species and of ecosystems. See also: Ecosystem, Ecosystem services.

Bioenergy

Energy derived from any form of biomass or its metabolic by-products.