Article | Published:

Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation

Nature Climate Change volume 5, pages 475480 (2015) | Download Citation

  • A Corrigendum to this article was published on 24 September 2015

This article has been updated

Abstract

Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC.

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Change history

  • 03 September 2015

    In the version of this Article originally published, in Fig. 1 the data plotted were for the calendar month of December and not the annual mean data. This has been replaced with a new global temperature trend map for annual mean data, in which (due to the reduced variability of annual as compared with monthly data) the cooling patch in the subpolar North Atlantic stands out even more. The first sentence of the caption for Fig. 1 has been amended to: 'Linear trends of annual surface temperature since AD 1901'. None of the conclusions in the Article are affected by this error.

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Acknowledgements

We thank O. Sherwood for providing coral data. M.E.M. acknowledges support for this work from the ATM program of the National Science Foundation (grant ATM-0902133).

Author information

Affiliations

  1. Potsdam Institute for Climate Impact Research (PIK), Earth System Analysis, Potsdam 14473, Germany

    • Stefan Rahmstorf
    • , Georg Feulner
    • , Alexander Robinson
    •  & Erik J. Schaffernicht
  2. Geologic Survey of Denmark and Greenland (GEUS), Østervoldgade 10, Copenhagen 1350, Denmark

    • Jason E. Box
  3. Pennsylvania State University, Department of Meteorology, University Park, Pennsylvania 16802, USA

    • Michael E. Mann
  4. Environmental Systems Institute (EESI), University Park, Pennsylvania 16802, USA

    • Michael E. Mann
  5. Universidad Complutense de Madrid, Dpto Astrofísica y CC de la Atmósfera, Madrid 28040, Spain

    • Alexander Robinson
  6. Instituto de Geociencias, UCM-CSIC, Madrid 28040, Spain

    • Alexander Robinson
  7. Department of Environmental Science, Roger Williams University, Bristol, Rhode Island 02809, USA

    • Scott Rutherford

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Contributions

S.Rahmstorf conceived and designed the research and wrote the paper, E.J.S., S.Rutherford, A.R. and G.F. performed the research, M.E.M. and J.E.B. contributed materials/analysis tools and co-wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Stefan Rahmstorf.

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DOI

https://doi.org/10.1038/nclimate2554

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