TY - JOUR

T1 - Confidence levels and likelihood terms in IPCC reports

T2 - a survey of experts from different scientific disciplines

AU - Kause, Astrid

AU - Bruine de Bruin, W.

AU - Persson, Johannes

AU - Thorén, H.

AU - Olsson, L.

AU - Wallin, A.

AU - Dessai, S.

AU - Vareman, N.

N1 - Open Access funding enabled and organized by Projekt DEAL. The research was funded by the Swedish Research Council Formas Linnaeus grant LUCID, Lund University Centre of Excellence for Integration of Social and Natural Dimensions of Sustainability (259–2008-1718; to AK, JP, HT, LO, and NV); the Swedish Foundation for Humanities and Social Sciences’ VBE program, Science and Proven Experience (M14-0138:1; to WBdB, JP, NV, and AW); the Center for Climate and Energy Decision Making (CEDM) through a cooperative agreement between the National Science Foundation and Carnegie Mellon University (SES–0949710 and SES–1463492; to WBdB). Publisher Copyright: © 2022, The Author(s).

PY - 2022/7/1

Y1 - 2022/7/1

N2 - 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.

AB - 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.

KW - Communication

KW - Confidence

KW - Expert judgment

KW - IPCC

KW - Probability

KW - Scientific assessment

KW - Uncertainty

KW - Psychology

UR - http://www.scopus.com/inward/record.url?scp=85133411661&partnerID=8YFLogxK

U2 - 10.1007/s10584-022-03382-3

DO - 10.1007/s10584-022-03382-3

M3 - Journal articles

AN - SCOPUS:85133411661

VL - 173

JO - Climatic Change

JF - Climatic Change

SN - 0165-0009

IS - 1-2

M1 - 2

ER -