AR6 Climate Change 2021:
The Physical Science Basis

The Working Group I contribution to the Sixth Assessment Report addresses the most up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science, and combining multiple lines of evidence from paleoclimate, observations, process understanding, and global and regional climate simulations.

Disclaimer: The Summary for Policymakers (SPM) is the approved version from the 14th session of Working Group I and 54th Session of the Intergovernmental Panel on Climate Change and remains subject to final copy-editing and layout.

The Technical Summary (TS), the full Report Chapters, the Annexes and the Supplementary Materials are the Final Government Distribution versions, and remain subject to revisions following the SPM approval, corrigenda, copy-editing, and layout. Although these documents still carry the note from the Final Government Distribution “Do Not Cite, Quote or Distribute” they may be freely published subject to the disclaimer above, as the report has now been approved and accepted.


CHANGING by Alisa Singer

Changing by Alisa Singer
"As we witness our planet transforming around us we watch, listen, measure … respond."
www.environmentalgraphiti.org – 2021 Alisa Singer.
 
IPCC has exclusive rights to "Changing". The artwork can only be reproduced as part of the cover of the WGI Summary for Policymakers. You may freely download and copy the front cover for your personal, non-commercial use, without any right to resell or redistribute it and provided that the IPCC will be acknowledged as the source of the material used. For any other use, permission is required. To obtain permission, please address your request to the IPCC Secretariat at ipcc-sec@wmo.int.


Summary for Policymakers

The Summary for Policymakers (SPM) provides a high-level summary of the understanding of the current state of the climate, including how it is changing and the role of human influence, and the state of knowledge about possible climate futures, climate information relevant to regions and sectors, and limiting human-induced climate change. (39 pages)


Technical Summary

The Technical Summary (TS) is designed to bridge between the comprehensive assessment of the Working Group I Chapters and its Summary for Policymakers (SPM). It is primarily built from the Executive Summaries of the individual chapters and atlas and provides a synthesis of key findings based on multiple lines of evidence. (150 pages)


Full report

The thirteen chapters of the Working Group I report provide an assessment of the current evidence on the physical science of climate change, knowledge evaluation gained from observations, reanalyses, paleoclimate archives and climate model simulations, as well as physical, chemical and biological climate processes. (1300 pages?)


Chapter 1: Framing, context, methods Download
Chapter 2: Changing state of the climate system Download
Chapter 3: Human influence on the climate system Download
Chapter 4: Future global climate: scenario-based projections and near-term information Download
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks Download
Chapter 6: Short-lived climate forcers Download
Chapter 7: The Earth's energy budget, climate feedbacks, and climate sensitivity Download
Chapter 8: Water cycle changes Download
Chapter 9: Ocean, cryosphere, and sea level change Download
Chapter 10: Linking global to regional climate change Download
Chapter 11: Weather and climate extreme events in a changing climate Download
Chapter 12: Climate change information for regional impact and for risk assessment Download
Atlas Download

Chapter 1: Framing, context, methods - Supplementary Material Download
Chapter 2: Changing state of the climate system - Supplementary Material Download
Chapter 3: Human influence on the climate system - Supplementary Material Download
Chapter 4: Future global climate: scenario-based projections and near-term information - Supplementary Material Download
Chapter 5: Global carbon and other biogeochemical cycles and feedbacks - Supplementary Material Download
Chapter 6: Short-lived climate forcers - Supplementary Material Download
Chapter 7: The Earth's energy budget, climate feedbacks, and climate sensitivity - Supplementary Material Download
Chapter 8: Water cycle changes - Supplementary Material Download
Chapter 9: Ocean, cryosphere, and sea level change - Supplementary Material Download
Chapter 10: Linking global to regional climate change - Supplementary Material Download
Chapter 11: Weather and climate extreme events in a changing climate - Supplementary Material Download
Chapter 12: Climate change information for regional impact and for risk assessment - Supplementary Material Download
Atlas - Supplementary Material Download

Annex I Observational Products Download
Annex II Models Download
Annex III Radiative Forcing Download
Annex IV Modes of Variability Download
Annex V Monsoons Download
Annex VI Climatic Impact-Driver and Extreme Indices Download
Annex VII Glossary Download

Errata

The IPCC decided in May 2011 to adopt an IPCC Protocol for Addressing Possible Errors in IPCC Assessment Reports, Synthesis Reports, Special Reports or Methodology Reports.

Read the Protocol here: ipcc_error_protocol_en.pdf

In case of a suspected error in an IPCC report, please send a mail to ipccerrorprotocol@wmo.int containing the following information:


Interactive Atlas

The novel AR6 Working Group I Interactive Atlas allows for a flexible spatial and temporal analysis of both data-driven climate change information and assessment findings in the report. It includes two components:

Link to the Interactive Atlas: https://interactive-atlas.ipcc.ch/

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Frequently Asked Questions

Frequently Asked Questions (FAQs) explain important processes and aspects that are relevant to the whole report for a broad audience and help to interpret the report. They are related to the Chapter they are assigned to, but can be relevant to multiple Chapters. (34 FAQs)


Regional Fact Sheets

Regional fact sheets are an outreach product that is fully traceable to the Chapters, the Technical Summary and the Interactive Atlas. They constitute an entry point for regionalized information in the AR6 Working Group I report. (11 fact sheets)

Introduction Download
Africa Download
Asia Download
Australasia Download
Central and South America Download
Europe Download
Mountains Download
North and Central America Download
Ocean Download
Polar regions Download
Small Islands Download
Urban areas Download
Contributors Download


Data Access

Data for SPM figures is available from the following weblink:
CEDA Catalogue

Click on ‘Datasets’ under Related Records to view the catalogue records for each SPM figure and to access the corresponding data. The Abstract field of these catalogue records contains detailed information about the data, including how it should be cited. The data is made available under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

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Outreach Materials

Use the links below to access the slides presented at the 9 August 2021 press briefing and a slide deck containing the Headline Statements and figures from the Summary for Policymakers.

IPCC Press Release on the Working Group I Contribution to the Sixth Assessment Report.