Abstract

The reasons for concern framework communicates scientific understanding about risks in relation to varying levels of climate change. The framework, now a cornerstone of the IPCC assessments, aggregates global risks into five categories as a function of global mean temperature change. We review the framework's conceptual basis and the risk judgments made in the most recent IPCC report, confirming those judgments in most cases in the light of more recent literature and identifying their limitations. We point to extensions of the framework that offer complementary climate change metrics to global mean temperature change and better account for possible changes in social and ecological system vulnerability. Further research should systematically evaluate risks under alternative scenarios of future climatic and societal conditions.

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  • Corrected online 06 January 2017

    In the print version of this Review, references 6, 9, 10, 19, 22, 26, 32, 35, 36, 46, 54, 68–71, 74, 79, 100, 101 and 102 contained errors. These errors have been corrected in the online version.

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Acknowledgements

K.T. gratefully acknowledges research support of the Environment Research and Technology Development Fund (S-10-1) provided by the Ministry of the Environment, Japan. P.M. and J.-P.v.Y. gratefully acknowledge research support provided by the Belgian Science Policy Office (BELSPO). We thank Y. Estrada and L. White for assistance with figures.

Author information

Affiliations

  1. National Center for Atmospheric Research, Boulder, Colorado 80305, USA

    • Brian C. O'Neill
  2. Department of Geosciences and the Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, New Jersey 08544, USA

    • Michael Oppenheimer
    •  & Rachel Licker
  3. Tyndall Centre for Climate Change, School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK

    • Rachel Warren
    •  & Jeff Price
  4. Climate Change Group, World Bank, Washington DC 20433, USA

    • Stephane Hallegatte
  5. Department of Earth and Planetary Sciences, Rutgers Energy Institute and Institute of Earth, Ocean and Atmospheric Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA

    • Robert E. Kopp
  6. Marine Biology/Ecological and Evolutionary Physiology, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany

    • Hans O. Pörtner
  7. University of the Witwatersrand, Johannesburg 2050, South Africa

    • Robert Scholes
  8. Institute of Spatial and Regional Planning, University of Stuttgart, Stuttgart 70569, Germany

    • Joern Birkmann
  9. Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa

    • Wendy Foden
  10. Carnegie Institution for Science, Department of Global Ecology, Stanford, California 94305, USA

    • Katharine J. Mach
    •  & Michael D. Mastrandrea
  11. Earth and Life Institute, Université catholique de Louvain, Louvain-la-Neuve B-1348, Belgium

    • Phillippe Marbaix
    •  & Jean-Pascal van Ypersele
  12. National Institute for Environmental Studies, Tsukuba 305-8506, Japan

    • Kiyoshi Takahashi
  13. Department of Economics, Wesleyan University, Middletown, Connecticut 06459, USA

    • Gary Yohe

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Contributions

B.C.O. and M.O. led the design of the study. B.C.O. led, and M.O. contributed to, the coordination of the paper. M.O., R.W., S.H., R.E.K., B.C.O., H.O.P., and B.S. led the drafting of subsections of the paper. B.C.O., P.M., R.L., K.J.M., M.M., and K.T. led the development of figures. All authors contributed to writing and/or editing the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Brian C. O'Neill.

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    IPCC reasons for concern regarding climate change risks

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https://doi.org/10.1038/nclimate3179