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Lennart Olsson, LUCSUS

Lennart Olsson

Professor, Docent

Lennart Olsson, LUCSUS

Confidence levels and likelihood terms in IPCC reports : a survey of experts from different scientific disciplines

Author

  • Astrid Kause
  • Wändi Bruine De Bruin
  • Johannes Persson
  • Henrik Thorén
  • Lennart Olsson
  • Annika Wallin
  • Suraje Dessai
  • Niklas Vareman

Summary, in English

Scientific assessments, such as those by the Intergovernmental Panel on Climate Change (IPCC), inform policymakers and the public about the state of scientific evidence and related uncertainties. We studied how experts from different scientific disciplines who were authors of IPCC reports, interpret the uncertainty language recommended in the Guidance Note for Lead Authors of the IPCC Fifth Assessment Report on Consistent Treatment of Uncertainties. This IPCC guidance note discusses how to use confidence levels to describe the quality of evidence and scientific agreement, as well likelihood terms to describe the probability intervals associated with climate variables. We find that (1) physical science experts were more familiar with the IPCC guidance note than other experts, and they followed it more often; (2) experts’ confidence levels increased more with perceptions of evidence than with agreement; (3) experts’ estimated probability intervals for climate variables were wider when likelihood terms were presented with “medium confidence” rather than with “high confidence” and when seen in context of IPCC sentences rather than out of context, and were only partly in agreement with the IPCC guidance note. Our findings inform recommendations for communications about scientific evidence, assessments, and related uncertainties.

Department/s

  • Theoretical Philosophy
  • Joint Faculties of Humanities and Theology
  • LUCSUS (Lund University Centre for Sustainability Studies)
  • Cognitive Science
  • Practical Philosophy
  • VBE
  • Medical Ethics

Publishing year

2022-07-04

Language

English

Publication/Series

Climatic Change

Volume

173

Document type

Journal article

Publisher

Springer

Topic

  • Climate Research

Keywords

  • Uncertainty
  • communication
  • confidence
  • probability
  • expert judgment
  • scientific assessment
  • IPCC
  • uncertainty
  • Communication
  • Confidence
  • Probability
  • Expert judgment
  • Scientific assessment
  • IPCC

Status

Published

Research group

  • VBE

ISBN/ISSN/Other

  • ISSN: 0165-0009