Climatic Change http://doi.org/pzb (2013)

The Intergovernmental Panel on Climate Change (IPCC) communicates information on risk and uncertainty with probabilistic statements and provides the inferred numerical ranges at the outset of the reports. However, interpretations of those expressions by non-experts can vary.

Evidence has shown that words such as 'likely' are subject to personal interpretations, even with guidance about the implied probability range. Translation of statements into different languages also raises issues of cross-cultural interpretations. Adam Harris, of University College London, UK, and colleagues analysed how the British and Chinese public interpret the IPCC's probabilistic phrases in the absence of information on numerical ranges. They surveyed university students (Study 1) and people approached in parks (Study 2) in both China and the UK, and found that their understanding differed from the IPCC's numbers. Chinese participants provided a broader variety of interpretations and departed much more from the IPCC's numbers than British participants. The researchers recommend increased use of numerical ranges in IPCC reports.