Ice-free Arctic projections under the Paris Agreement

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Under the Paris Agreement, emissions scenarios are pursued that would stabilize the global mean temperature at 1.5–2.0 °C above pre-industrial levels, but current emission reduction policies are expected to limit warming by 2100 to approximately 3.0 °C. Whether such emissions scenarios would prevent a summer sea-ice-free Arctic is unknown. Here we employ stabilized warming simulations with an Earth System Model to obtain sea-ice projections under stabilized global warming, and correct biases in mean sea-ice coverage by constraining with observations. Although there is some sensitivity to details in the constraining method, the observationally constrained projections suggest that the benefits of going from 2.0 °C to 1.5 °C stabilized warming are substantial; an eightfold decrease in the frequency of ice-free conditions is expected, from once in every five to once in every forty years. Under 3.0 °C global mean warming, however, permanent summer ice-free conditions are likely, which emphasizes the need for nations to increase their commitments to the Paris Agreement.

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  1. 1.

    Cohen, J. et al. Recent Arctic amplification and extreme mid-latitude weather. Nat. Geosci. 7, 627–637 (2014).

  2. 2.

    IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T.F. et al.) (Cambridge Univ. Press, 2013).

  3. 3.

    Adoption of the Paris Agreement FCCC/CP/2015/L.9/Rev.1 (UNFCCC, 2015).

  4. 4.

    Rogelj, J. et al. Paris Agreement climate proposals need boost to keep warming well below 2 °C. Nat. Clim. Change 534, 631–639 (2016).

  5. 5.

    Mitchell, D. et al. Realizing the impacts of a 1.5 °C warmer world. Nat. Clim. Change 6, 735–737 (2016).

  6. 6.

    James, R., Washington, R., Schleussner, C. F., Rogelj, J. & Conway, D. Characterizing half-a-degree difference: a review of methods for identifying regional climate responses to global warming targets. WIRES Clim. Change 8, e457 (2017).

  7. 7.

    Screen, J. A. & Williamson, D. Ice-free Arctic at 1.5 °C? Nat. Clim. Change 7, 230–231 (2017).

  8. 8.

    Sanderson, B. M. Community Climate Simulations to assess avoided impacts in 1.5 °C and 2 °C futures. Earth Syst. Dynam. 8, 827–847 (2017).

  9. 9.

    Wang, M. & Overland, J. E. A sea ice free summer Arctic within 30 years? Geophys. Res. Lett. 36, L07502 (2009).

  10. 10.

    Laliberté, F., Howell, S. E. L. & Kushner, P. J. Regional variability of a projected sea ice-free Arctic during the summer months. Geophys. Res. Lett. 43, 256–263 (2016).

  11. 11.

    Sigmond, M. & Fyfe, J. C. Tropical Pacific impacts on cooling North American winters. Nat. Clim. Change 6, 970–975.

  12. 12.

    Gillett, N. P., Arora, V. K., Zickfeld, K., Marshall, S. J. & Merryfield, W. J. Ongoing climate change following a complete cessation of carbon dioxide emissions. Nat. Geosci. 4, 83–87 (2011).

  13. 13.

    Swart, N. C., Fyfe, J. C., Hawkins, E., Kay, J. E. & Jahn, A. Influence of internal variability on Arctic sea-ice trends. Nat. Clim. Change 5, 86–89 (2015).

  14. 14.

    Massonnet, F. et al. Constraining projections of summer Arctic sea ice. Cryosphere 6, 1383–1394 (2012).

  15. 15.

    Fetterer, F., Knowles, K., Meier, W. & Savoie, M. Sea Ice Index (National Snow and Ice Data Center, Boulder, CO).

  16. 16.

    Rogelj, J., Schleussner, C. F. & Hare, W. Getting it right matters: temperature goal interpretations in geoscience research. Geophys. Res. Lett. 44, 10662–10665 (2017).

  17. 17.

    Mahlstein, I. & Knutti, R. September Arctic sea ice predicted to disappear near 2 °C global warming above present. J. Geophys. Res. Atmos. 117, D06104 (2012).

  18. 18.

    Rosenblum, E. & Eisenman, I. Sea ice trends in climate models only accurate in runs with biased global warming. J. Clim. 30, 6265–6278 (2017).

  19. 19.

    Notz, D. & Stroeve, J. Observed Arctic sea-ice loss directly follows anthropogenic CO2 emission. Science 354, 747–750 (2016).

  20. 20.

    Arora, V. K. et al. Carbon emission limits required to satisfy future representative concentration pathways of greenhouse gases. Geophys. Res. Lett. 38, L05805 (2011).

  21. 21.

    Meinshausen, M. et al. The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Climatic Change 109, 213–241 (2011).

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We acknowledge the Canadian Sea Ice and Snow Evolution Network for proposing the CanESM2 Large Ensemble simulations and the modelling groups, the Program for Climate Model Diagnosis and Intercomparison, and the WCRP Working Group on Coupled Modelling for their roles in making available the WCRP CMIP5 multimodel data set. We thank W. Lee and Y. Jiao for technical assistance and B. Merryfield and S. Howell for their helpful comments on an earlier draft.

Author information


  1. Canadian Centre for Climate Modelling and Analysis, Environment and Climate Change Canada, Victoria, British Columbia, Canada

    • Michael Sigmond
    • , John C. Fyfe
    •  & Neil C. Swart


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M.S. conceived the project, designed the experiments, performed the analysis and wrote the manuscript. J.C.F. helped with the analysis and helped write the manuscript. N.C.S. helped design the experiments and edited the manuscript.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Michael Sigmond.