I was a lead author of two chapters in the AR2 WG3 report (1995), a convening lead author in the WG2 Special Report on Regional Impacts (1998), a contributing author of one chapter in the AR3 WG1 report (2001), a lead author of one chapter in the AR3 WG2 report (2001), and a contributing author of one chapter in the AR4 WG2 report (2007). I am designated to be a convening lead author for AR5 WG2 (2014).
The IPCC is a victim of its own success. Policy makers trust the IPCC reports as neutral and authoritative assessments of climate research. Therefore, people with a political agenda have tried to influence the IPCC. Such attempts were largely in vain in AR2 and AR3, but this is not true for AR4. Working Group 2 systematically portrays climate change as a bigger problem than is scientifically acceptable. (Examples include the date of disappearance for glaciers in the Himalayas, the mix-up on weather and climate for agriculture in Africa, and the projected number of people at risk from water stress.) Working Group 3 systematically portrays climate policy as easier and cheaper than can be responsibly concluded from academic research. (Examples include the attribution of market-driven and welfare-improving improvements in energy efficiency to climate policy, the omission of the opportunity costs of energy research and development, and the use of gross (rather than net) estimates of job creation.) These biases can be found in the chapters, the technical summaries, the summaries for policy makers, and the synthesis report.
The most important problem of the IPCC is the nomination and selection of authors and Bureau Members. Some experts are included or excluded because of their political allegiance rather than their academic quality. Sometimes, the “right” authors are put in key positions with generous government grants to support their IPCC work, while the “wrong” authors are sidelined to draft irrelevant chapters and sections without any support.
AR5 should be put on hold until the IPCC can prove that its author teams indeed have the relevant expertise, and its authors are at least as qualified as their peers. If needed, the IPCC should request additional nominations.
The IPCC member states are represented by their environment departments. For AR6, this responsibility should be transferred to their research departments or their academies. The selection process for authors and Bureau Members should be made transparent. The IPCC should commission a scientometric assessment of its Bureau Members, authors, and chapters.
IPCC assessment reports do not cover the entire literature. For instance, the IPCC does not fully assess the literature on trade-offs between the various greenhouse gases and the literature on international environmental treaties. Both areas are actively researched and conclusions are typically critical of current policy, but were largely omitted from previous IPCC reports. The literature on comparing the impacts of climate change to the costs of emission reduction falls outside WG2 and WG3, and thus outside the Synthesis Report as well. There is a risk that the nascent literature on ex-post evaluations of climate policy (in Europe and Japan) will be ignored in AR5, and particularly those papers that show that climate policy is ineffective and needlessly expensive.
The IPCC should submit the proposed outline for AR5 for peer review, and ensure that it covers all aspects of climate change and climate policy, including those parts of the academic literature that are potentially embarrassing to policy makers.
The IPCC Plenary has delegated its supervisory powers to the IPCC Bureau, which is also its executive. This implies that there is no mechanism to correct the IPCC Chair (if, for example, he oversteps his mandate and gives policy advice on behalf of the IPCC, if he says embarrassing things to journalists, or if he uses the IPCC to raise funds for his home institution). There is no mechanism to reconcile differences between IPCC Working Groups on the treatment of interdisciplinary topics. (The main example is the IPCC treatment of global warming potentials as a pure physical issue.) Therefore, the Chairs of the IPCC and its Working Groups should leave the IPCC Bureau, and the Bureau should adopt a supervisory role under a strong and independent chairperson.
In contrast to the procedures for governing the IPCC and selecting its authors and officials, the procedures for drafting IPCC reports are acceptable on paper but not in practice. Particularly, these procedures were not enforced in AR4 WG2 and WG3. (Some chapters rely heavily on gray literature while ignoring peer-reviewed literature on the same matter (e.g., Ch 7 WG2). Other chapters cite papers published after the deadline (e.g., Ch 15 WG2). Incomplete drafts were sent for peer-review (e.g., Ch 11 WG3). Substantial material was added after the final review (e.g., Ch 20 WG2).) In order to avoid repetition, Review Editors should be more independent, and return chapters for further revision if needed. The Review Editors rather than the Convening Lead Authors should have the final say about chapters. Review Editors should actively seek the input of referees. Review Editors should have the right to reject sections of the report that do not meet basic quality standards at the deadline. In short, Review Editors should have the same powers as journal editors. Review Editors should be selected from the ranks of (former) journal editors.
The IPCC should engage the wider public in the review process. After the publication of AR4, the “blogosphere” uncovered a large number of procedural and substantial errors. It would be preferable to discover this before publication. Engaging with “the public” is difficult. Therefore, the IPCC should do this in an experimental fashion in AR5 so as to prepare guidelines for AR6. Experiments could include posting draft chapters on blogs for public comment (A draft of the current statement was discussed at http://rogerpielkejr.blogspot.com/2010/05/richard-tols-draft-submission-to-iac.html), and posting draft chapters on wikis for public amendment.