Article

Climatic Change

, Volume 108, Issue 4, pp 675-691

Open Access This content is freely available online to anyone, anywhere at any time.

The IPCC AR5 guidance note on consistent treatment of uncertainties: a common approach across the working groups

  • Michael D. MastrandreaAffiliated withIPCC Working Group II Technical Support Unit, Carnegie Institution for Science Email author 
  • , Katharine J. MachAffiliated withIPCC Working Group II Technical Support Unit, Carnegie Institution for Science
  • , Gian-Kasper PlattnerAffiliated withIPCC Working Group I Technical Support Unit, University of BernClimate and Environmental Physics, Physics Institute, University of Bern
  • , Ottmar EdenhoferAffiliated withPotsdam Institute for Climate Impact Research (PIK)Faculty Planning Building Department, Technical University Berlin
  • , Thomas F. StockerAffiliated withClimate and Environmental Physics, Physics Institute, University of BernOeschger Centre for Climate Change Research, University of Bern
  • , Christopher B. FieldAffiliated withDepartment of Global Ecology, Carnegie Institution for Science
  • , Kristie L. EbiAffiliated withIPCC Working Group II Technical Support Unit, Carnegie Institution for Science
  • , Patrick R. MatschossAffiliated withIPCC Working Group III Technical Support Unit, Potsdam Institute for Climate Impact Research (PIK)

Abstract

Evaluation and communication of the relative degree of certainty in assessment findings are key cross-cutting issues for the three Working Groups of the Intergovernmental Panel on Climate Change. A goal for the Fifth Assessment Report, which is currently under development, is the application of a common framework with associated calibrated uncertainty language that can be used to characterize findings of the assessment process. A guidance note for authors of the Fifth Assessment Report has been developed that describes this common approach and language, building upon the guidance employed in past Assessment Reports. Here, we introduce the main features of this guidance note, with a focus on how it has been designed for use by author teams. We also provide perspectives on considerations and challenges relevant to the application of this guidance in the contribution of each Working Group to the Fifth Assessment Report. Despite the wide spectrum of disciplines encompassed by the three Working Groups, we expect that the framework of the new uncertainties guidance will enable consistent communication of the degree of certainty in their policy-relevant assessment findings.