Review Process









The multi-stage review process is an important part of an IPCC assessment. In successive stages, expert reviewers and governments are invited to comment on the accuracy and completeness of the scientific, technical, and socio-economic content and the overall balance of the report drafts. The review process includes a very wide circulation among expert reviewers and government experts, with hundreds of reviewers checking the accuracy and completeness of the scientific assessment contained in the drafts. In the Expert Reviews of the IPCC Fifth Assessment Report, the three WGs encouraged as wide a participation of experts as possible, relying on a self-declaration of expertise.

The Expert Review of the First Order Draft (FOD) of the WGII contribution to the IPCC Fifth Assessment Report: Climate Change 2014: Impacts, Adaptation, and Vulnerability (WGII AR5) took place from 11 June 2012 to 6 August 2012. Over 1700 individuals registered as Expert Reviewers, with 528 reviewers submitting a total of 19,598 review comments. These served as the basis for discussions at the Third Lead Author Meeting, which was held in Buenos Aires, Argentina (23-26 October 2012).

The Expert and Government Review of the Second Order Draft (SOD) of the WGII AR5 took place from 28 March to 24 May 2013. This was the opportunity for experts and governments to comment on the Second Order Draft of the chapters and the First Order Draft of the Technical Summary and the Summary for Policymakers. Observer Organizations were invited to encourage experts to sign up as expert reviewers. Over 2600 individuals registered as Expert Reviewers. The review generated 28,544 comments from 1271 experts and 33 governments. These comments served as the basis for deliberations at the Fourth Lead Author Meeting, held in Bled, Slovenia (15-19 July 2013).

On 28 October 2013, the Final Draft of WGII AR5 was completed, comprising 30 Chapters, a Technical Summary and a Summary for Policymakers. The Final Draft was made available to the Governments during the Final Government Distribution from 28 October to 20 December 2013. The Final Government Distribution (FGD) provided governments with an opportunity to submit written comments on the Final Draft Summary for Policymakers in preparation of the 10th Session of Working Group II. A total of 2350 comments were received from 45 governments.

In accordance with Article 4.2 of Appendix A to the Principles Governing IPCC Work, all comments submitted as part of the formal expert and/or government review together with the author responses will be made available on the WGII AR5 web site as soon as possible after finalisation of the report.

  Expert Reviewers Countries Governments Comments
First Order Draft 528 60   19598
Second Order Draft 1271 67 33 28544
Final Government Distribution     45 2350


Press / Media Contact

IPCC Working Group II
Technical Support Unit (TSU)
260 Panama Street
Stanford, CA 94305, USA
Phone: (+1) 650.353.4257