Published: 23 Apr 2020

The Intergovernmental Panel on Climate Change (IPCC) has extended government and expert review of the second order draft of the Working Group I contribution to the Sixth Assessment Report (AR6) by six weeks to allow reviewers more time in the light of disruption caused by the COVID-19 pandemic.

The Expert Review of the Second Order Draft Draft of the Working Group I Contribution to the IPCC Sixth Assessment Report is running from 2 March 2020 to 5 June 2020.

The review, which opened on 2 March 2020, will close on 5 June. Interested experts can register until midnight CET on 29 May.

The review process is crucial for the quality of IPCC assessment reports. It is essential for its exhaustivity, objectivity and rigour, said Valérie Masson-Delmotte and Panmao Zhai, Co-Chairs of Working Group I in a joint statement.

IPCC reports go through repeated drafts and reviews to help ensure that the report provides a balanced and comprehensive assessment of the latest scientific findings.

The Working Group I contribution to the AR6, Climate Change 2021: The Physical Science Basis, will assess large-scale climate changes, climate processes and feedback and regional climate information. The Working Group I report includes an interactive online atlas, which is also open for review comments.

The draft report has been prepared by 233 authors from 65 countries.

During the review, experts may comment on the structure and comprehensiveness of the report and suggest improvements on the presentation of materials graphically or through tables. They may also propose revisions, relevant additional papers with their full citation, and editorial changes for readability and concision. This version also includes the first drafts of the Technical Summary and Summary for Policymakers.

IPCC reports undergo multiple stages of reviews, first by experts and then by both governments and experts.  Experts who commented on the first draft will also be invited to comment on this second order draft. All expert reviewers will be acknowledged in the published report. This was originally due to be finalized in April 2021, but along with other IPCC reports and activities may be delayed because of the pandemic.

The first order draft of the Working Group I report received 23,462 comments from 750 expert reviewers. So far, 2,277 experts have registered to review the second order draft.