The Peer Review Process
The IPCC’s technical reports derive their credibility principally from an extensive, transparent, and iterative peer review process that, as mentioned above, is considered far more exhaustive than that associated with scientific journals. This is due to the number of reviewers, the breadth of their disciplinary backgrounds and scientific perspectives, and the inclusion of independent “review editors” who certify that all comments have been fairly considered and appropriately resolved by the authors. For example, see [2].
To be as inclusive and open as possible, a balanced review effectively begins with the choice of lead authors. By intentionally including authors who represent the full range of expert opinion, many areas of disagreement can be worked out in discussions among the authors rather than waiting until the document is sent out for review.
The first round of review is conducted by a large number of expert reviewers—more than 2,500 for the entire AR4—who include scientists, industry representatives, and NGO experts with a wide range of perspectives. Lead authors are required to consider all comments and incorporate those with scientific merit—a process overseen by review editors (two per chapter) who have expertise in the specific topic covered by a given chapter. All review comments are archived together with the authors’ responses and/or resulting actions, and are available upon request.
If major differences emerge, lead authors are encouraged to organize a meeting with both the contributing authors and review editors to discuss and resolve the differences. The goal is not to reach a potentially “watered-down” compromise that conceals scientific uncertainties or real differences in expert opinion, but to produce a report of the highest scientific integrity, reflecting the state of our understanding fairly and adequately.
The revised draft is then sent back to the expert reviewers and also to government representatives for the so-called government review stage. Each government is entitled to organize any type of review process it deems appropriate. The U.S. government, for example, seeks comments from agencies, scientific experts, and the general public (through a notice in the Federal Register) as the starting point for its comments. Again, lead authors prepare revisions in response to scientifically valid comments, and encourage reviewers and other experts to resolve any remaining major differences by communicating directly. The resulting document is then submitted to the working group’s plenary session for consideration and acceptance.
