IPCC WorkiNG group II

WGII Background on the IPCC Review Process and the Status of Early Drafts of IPCC Reports


13 January 2012


The IPCC is committed to preparing reports that meet the highest possible standards of scientific excellence, balance, and clarity. To meet these high standards, every chapter of every IPCC report undergoes several iterations and two formal reviews. Due to their nature, early drafts can be rough and are incomplete. Partly, this reflects the fact that literature continues to be published during an assessment so earlier drafts do not include the newest publications. More importantly, early drafts have not benefited from extensive review and evaluation by the scientific community. The author teams refine successive drafts based on review comments from scientific experts. The IPCC has more than twenty years of experience demonstrating that refining reports through several stages of drafts and expert review consistently enhances the quality of reports.


The IPCC seeks expert reviews from the broadest possible range of experts, in a process that includes two formal rounds of reviews by individual scientific experts and one round of review by governments. The preliminary draft of each chapter, also called the zero-order draft, is reviewed by experts invited to comment on the breadth of coverage and structure of the chapter. The states of development of these drafts are such that comments from a handful of thoughtful reviewers are sufficient to identify the major areas that need work. The process then shifts to make the expert reviewer base as broad as possible. All relevant experts are invited to provide review comments on the two rounds of formal drafts, termed the first-order draft and the second-order draft by the IPCC. Registration to serve as an expert reviewer of the first-order draft of the WGII contribution to the AR5 will open in June 2012. For the second-order draft, which will be reviewed in 2013, both scientific experts and governments are invited to provide review comments.


The IPCC requires that author teams provide a response to every review comment submitted in the expert review of the first-order draft and in the subsequent expert and government review of the second-order draft. IPCC assigns a dedicated group, usually two to four scientists for each chapter, to monitor the process of responding to each comment and to confirm that the responses are consistent with the chapter revisions. These scientists, called "Review Editors" by the IPCC, perform a uniquely important role in ensuring that the finished report derives the maximum possible benefit from the repeated cycle of drafting, review, and revision.


When a completed assessment report is released, the first-order and second-order drafts are released, along with all of the review comments and the responses to the review comments from the author teams. This approach provides not only the final product of the IPCC process but also the record of how the report evolved through drafts, comments, and revision.


The IPCC does not publicly release drafts prior to the completion of a report because the contents of the early drafts may not meet the IPCC's high standards of excellence, balance, and clarity. Therefore, reviewers and authors are asked not to cite, post, or share drafts. These early drafts are not confidential in the sense that they are hidden, protected, or secret. To the contrary, the success of the process depends on cycles of extensive expert review. All scientists with the expertise to improve and strengthen the reports are encouraged to register and provide review comments on the first- and second-order drafts.