Policy ForumClimate Change

Added value from IPCC approval sessions

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Science  02 Oct 2015:
Vol. 350, Issue 6256, pp. 36
DOI: 10.1126/science.aaa8976

Approval sessions of the Intergovernmental Panel on Climate Change (IPCC) generate broadly shared ownership of scientific knowledge on climate change—a key contribution to the influence of IPCC reports (1, 2). Yet several recent essays have highlighted weaknesses of the approval process (3, 4). We draw on our experience cochairing Working Group II to provide some balance and to characterize important strengths. Although the governmental approval process can be cumbersome, sleep-depriving, and tinged with risk of political influence (5), successful approval sessions sharpen policy-relevant findings to make them more clear and useful (6).

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IPCC summaries for policy-makers (SPMs) are approved line by line, by consensus of all participating governments. Typically, approval sessions involve 100 to 150 countries, plus senior representatives of the IPCC author team (1, 7). Given the high stakes and wide attention, it is hard to imagine approval sessions getting beyond the first few lines. Yet SPMs, many pages in length, get approved, usually with only minor changes to most content, cementing the status of the SPM and entire report as the definitive assessment of the state of knowledge on climate-change science. No other products of the scientific community achieve anything similar.

Extensive involvement of governments in approving SPMs can create the risk of political tinkering with the scientific findings. But this risk can be managed. The key is flexible author teams focused on the essence of each issue, interacting creatively with country delegates to craft solutions that address concerns while maintaining accuracy, rigor, and balance. Commentators have critiqued the sometimes inelegant or jargon-laden wording of IPCC findings (8). It is difficult to phrase complex, subtle findings in a way that is accessible, crisp, and not susceptible to misinterpretation. That is where the approval process almost always helps.

Approval sessions are efficient for identifying text or figures that cause problems. The hard part is identifying improvements that work. Issues often arise because material is unclear, hard to put into context, seemingly inconsistent with the underlying evidence, or subject to alternative interpretations. For concerns like these, approval sessions reliably lead to text and graphics with better precision and clarity. Of course, the results are not always entirely positive, especially if author teams too narrowly circumscribe a definition of the “correct” scientific expression. In the process, authors and country delegates must be willing to stretch to find common solutions.

Other times, issues arise based not on accuracy but on potential implications for upcoming negotiations. The dynamics of an approval session can help keep this risk of politicization in check, but it has been a challenge, especially for some topics in the economic and political sciences (3, 4). Failure to find common ground can result in limited coverage of particular issues in an SPM, and it can lead to legitimate questions about the effectiveness of the IPCC in highlighting specific assessment topics.

There are many examples of the approval process leading to dramatic improvements. One example concerns the relationship between a change in the mean of some climate variable (e.g., temperature or precipitation) and the risk of extremes. This is a core concept for the IPCC special report, Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (9). The draft SPM did not have a conceptual figure illustrating possible relations between means and extremes, although there was a figure in the report itself. In crafting the draft SPM, the author team felt that the concept was too simple to require a figure. Through the approval process, countries emphasized the importance of strengthening the presentation of key concepts. Eventually, persuasive arguments from several countries made it clear that, without the figure, the report's other findings became too confusing for many users.

What are lessons for the future? There are many other issues that are large in scale and extended in time, that integrate a range of interacting natural and human processes, and that involve values, priorities, and attitudes about risk as well as scientific information. An IPCC-like process applied to such topics could help create shared ownership and strengthen the foundations for good decisions. The Intergovernmental Platform on Biodiversity and Ecosystem Services (10), explicitly designed to build on some key features of the IPCC, will provide a test of the model's replicability.

IPCC approval sessions add value to the science-policy interface. Still, SPMs are legitimately criticized for being too long (8), difficult to understand (8), and selective in their coverage (4). Some level of this may be an unavoidable consequence of an inclusive process that addresses complex issues. But past successes point to creative approaches for clearly communicating robust science, increasing its relevance for society.


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