Communication of uncertainty in the IPCC: A comparative international study

Fordham University, Bronx NY

Investigators

Abstract

The Intergovernmental Panel on Climate Change (IPCC) publishes periodical reports (assessments) informing policymakers and the public on issues related to global climate change. The IPCC uses verbal descriptions of uncertainty (such as unlikely) to convey the underlying imprecision of its forecasts and conclusions. Previous studies showed that the public interprets these probabilistic statements as less extreme than intended by the authors, and that there are large individual differences in the interpretation of these statements. These studies suggest that supplementing the probability words with numerical ranges would increase differentiation between terms and consistency of interpretation. Climate change is a global issue and the IPCC is a global body whose reports and conclusions are translated to many languages and have international impact. This project is a collaborative multi-national study of the of IPCC communication of uncertainty. We plan to administer translated questionnaires in many countries, to investigate cross-national differences in interpretation of probabilistic pronouncements, relate those to attitudes towards global climate change, and outline methods to improve the effectiveness of communication. Our results and recommendations should help improve the way the IPCC communicate uncertainty in its future reports.