The IPCC's 6th Assessment Report Climate Change 2021: The Physical Science Basis

Submitted by Lena Grobusch | published 14th Aug 2021 | last updated 12th Apr 2022
What is the IPCC's Sixth Assessment Report?
IPCC 6th Assessment Report 2021


The Working Group I (WG1) contribution to the IPCC's Sixth Assessment Report (AR6) 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 palaeoclimate, observations, process understanding, and global and regional climate simulations.

This article provides an overview of and links to the key outputs from the WG1 contribution. A video recording of the press conference held at the launch of this contribution is shared above.

You can also read about the two further reports in AR6, the WG2 adaptation report, and the WG3 mitigation report. 


  • 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 Although these documents still carry the note from the Final Government Distribution “Do Not Cite, Quote or Distribute” they may be freely published subject to the disclaimer above, as the report has now been approved and accepted.

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. 

The full Summary for Policymakers can be downloaded here.

*Download the full publication from the right hand column. The key messages from the publication are provided below. See the full text for much more detail.

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.

The Technical Summary can be downloaded here

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, palaeoclimate archives and climate model simulations, as well as physical, chemical and biological climate processes.

The full report from WG1 can be downloaded here

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:

  • The Regional Information component provides access to climate change information (variables and derived indices) from the main datasets used in the report.
  • The Regional Synthesis component allows the exploration of key synthesized assessments building on multiple lines of evidence across the Working Group I reference regions. This component supports the SPM and is being updated to align with the final approval version (to be presented in late September).

The Interactive Atlas can be found here.

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.

The FAQs can be downloaded here

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 can be downloaded via the website of the 6th Assessment Report, here.

Outreach Materials

Access the press conference slides from 9 August 2021 here. Watch the press conference below.

Further resources

  • Suggested citation for the Summary for Policymakers:

    • IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M. I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T. K. Maycock, T. Waterfield, O. Yelekçi, R. Yu and B. Zhou (eds.)]. Cambridge University Press. In Press.


    Further readings