IPCC Sixth Assessment Report (Working Group 1 Contribution): Climate Change 2021-The Physical Science Basis

The Working Group I contribution to the Sixth Assessment Report, Climate Change 2021: The Physical Science Basis is now out The 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.

The Sixth Assessment Report (AR6) comprises three Working Group contributions: Working Group I (the physical science basis), Working Group II (impacts, adaptation and vulnerability) and Working Group III (mitigation) and a Synthesis Report. The Synthesis Report integrates the three Working Group reports as well as the findings from the three cross-Working Group Special Reports prepared during this assessment cycle: Special Report on Global Warming of 1.5ºC (SR15, October 2018), Special Report on Climate Change and Land (SRCCL, August 2019) and Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC, September 2019). During the AR6 cycle the IPCC also updated its methodologies with the 2019 Refinement to the 2006 Guidelines on National Greenhouse Gas Inventories (May 2019).

Compared with previous IPCC assessments, there is a greater focus on solutions across all Working Groups, more regional information, and more integration across Working Groups (e.g. boxes on specific topics to which more than one Working Group has contributed and which may appear in more than one report). All reports in this cycle cover the topic of cities and climate change, ahead of a Special Report on this topic in the next assessment cycle.

Read more about the report contribution and download


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