Climate summaries 'for grownups,' but not too difficult for policymakers

Offering a rare insider analysis of the climate assessment process, Carnegie's Katharine Mach and colleagues at the Department of Global Ecology examined the writing and editing procedures by which the Intergovernmental Panel on Climate Change creates summaries of their findings for policymakers. Despite recent critiques that these summaries are too difficult for non-experts, Mach and colleagues found them comparable to reference texts in terms of reading comprehension level. Their results are published by Science Advances.

"Using multiple tools for measuring reading ease, we found that IPCC reports are designed for grownups, but they are not harder to read than other science documents, including those written for the public by professional writers," said co-author Chris Field, who served as the co-chair of the second IPCC Working Group.

Nevertheless, Mach and colleagues also suggest ways that the summary reports could be improved by using less jargon and more cohesive language to link the ideas they contain. The summaries could also be enhanced by graphics, videos, animations, and online multimedia, in addition to extensive media availability by panel leadership.

Mach and Field, together with Carnegie's Patrick Freeman and Michael Mastrandrea, also suggest the possibility of getting professional science editors to participate in the review process to help keep the writing as accessible as possible without losing meaning.

The process by which IPCC summary reports for policymakers are generated is quite singular, and often a subject of fascination.

Scientific experts spend years generating a report assessing the current state of climate science and then create summaries of each section, which are intended to aid policymakers in making the most of the information. These summaries are approved line by line, by consensus by a group of hundreds of government representatives and scientists, working for days at a time and even through the night until they have agreed upon every word.

Mach and her team undertook an in-depth analysis of the process by which these summaries are revised and approved.

"Despite the importance of these policymaker summaries, and the interest in their creation, the revision process has not been comprehensively analyzed until now," Mach explained.

They found that the review process generally increases the length of text, unless there is an issue of great political sensitivity, in which case the summary text might be shortened. Changes during in-person government session tend to focus on the comprehensiveness of examples provided and on increasing policy relevance. This is in contrast to changes in the text prior to the government approval session, which emphasized clarity and scientific rigor.

"Despite the exhausting rigor of the review process, the method of discussing and agreeing upon every sentence builds ownership of the science by both participating researchers and governments," Mach said. "The creation and revision of these summaries is a vital part of making climate science relevant for decision-making. Although there is some room for improvement, the finished documents can certainly provide a lot of value to participants, scientists and nonscientists alike."