Experts interested in serving as Expert Reviewers and providing scientific comments on the Second-Order Draft of the Working Group III contribution to the IPCC Sixth Assessment Report can register until midnight CET on 7 March 2021 at:
https://apps.ipcc.ch/comments/ar6wg3/sod/register.php

The IPCC is currently working on its next comprehensive report, AR6, and has opened the draft WG III contribution for a second review by experts and governments from 18 January to 14 March 2021. The second-order draft of the report includes the first drafts of the Summary for Policymakers and Technical Summary. All content builds on the First-Order Draft and the expert review comments submitted on that draft.

Reviews ensure that IPCC reports cover the most up to date scientific, technical and socio-economic findings, and are representative of a broad range of independent expertise from developed and developing countries. Authors will prepare a Final Draft based on the comments received during the second review. The Final Draft is distributed to governments at the time of the final government review of the Summary for Policymakers. The dates for the final government review of the Working Group III contribution to the AR6 are yet to be confirmed.

Source: IPCC official website – https://www.ipcc.ch/2021/01/04/pr-working-group-iii-ar6-sod/