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You are here: Home News Review of Working Group contributions to the IPCC 5th Assessment Report (AR5) has started

Review of Working Group contributions to the IPCC 5th Assessment Report (AR5) has started

The AR5, summarizing the state of scientific knowledge about climate change, is going through an elaborate system of drafting, review by experts and governments, and revision to ensure that it meets the highest standards, is comprehensive and reflects the published literature and a range of scientific viewpoints. The main stages of the IPCC review process are the review of the “first-order draft” (FOD) by scientific experts, the review of the “second-order draft” (SOD) by experts and governments and the government review of the final draft of the summary for policymakers. Following this, the final draft report and its summary for policymakers are submitted for acceptance and approval to the IPCC Plenary.

Experts who are interested in participating in an IPCC review are invited to register as expert reviewers, after which they will be provided access to the draft chapters. In order to allow authors to address all review comments in a comprehensive, efficient and transparent manner, it is essential that reviewers register and submit their comments through the process established by the Working Groups. The expert review of the first order draft of Working Group I (The Physical Science Basis) is in progress until 10 February 2012. For registration see

Subsequent reviews are scheduled as follows:

First Order Draft (FOD) expert review

 16 December 2011 – 10 February 2012
 WGII FOD  11 June – 6 August 2012
 WGIII FOD   22 June - 20 August 2012

Second Order Draft (SOD) government and expert review

 05 October – 30 November 2012
 WGII SOD  29 March – 24 May 2013
 WGIII SOD  25 February – 22 April 2013

For registration for the Working Group II (Impacts, Adaptation and Vulnerability) reviews see and for the Working Group III (Mitigation of climate Change) reviews see at the appropriate time.

In addition to the mandatory reviews, working groups may also prepare so-called “zero-order drafts” (ZOD) and circulate them for informal review. These zero-order drafts are incomplete, rough early drafts, partly due to the fact that literature continues to be published during an assessment. Scientific experts are invited to comment on the breadth of coverage and structure of a chapter in the ZOD, as important input for developing the FOD.

After a report is finalized, all drafts submitted for formal review, the review comments, and the responses by authors to the comments are made available on the IPCC and Working Group websites along with the final report [,,,,].

This makes it possible to track how IPCC reports were developed. However, as was decided by member governments in the IPCC plenary, draft reports prior to approval are considered “pre-decisional” in the language used in the IPCC procedures, which means they are not final or ready for distribution. Drafts of IPCC reports are not made public before the final document is approved because statements that these are work in progress may get lost and selective quotation could give wrong perceptions of science and misleading conclusions. Only the final Report will meet the IPCC’s high quality standards of scientific excellence, balance and clarity. Therefore, drafts are provided in confidence to reviewers and are not for public distribution, quotation or citation.

A more detailed description of the development of an IPCC report and its review processes and the full text of the procedures can be found here: (pdf file)

Text as pdf file

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