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    Observed fingerprint of a weakening Atlantic Ocean overturning circulation


    Caesar, Levke and Rahmstorf, Stefan and Robinson, A. and Feulner, G. and Saba, V. (2018) Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature, 556 (7700). pp. 191-196. ISSN 0028-0836

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    Abstract

    The Atlantic meridional overturning circulation (AMOC)—a system of ocean currents in the North Atlantic—has a major impact on climate, yet its evolution during the industrial era is poorly known owing to a lack of direct current measurements. Here we provide evidence for a weakening of the AMOC by about 3±1 sverdrups (around 15 per cent) since the mid-twentieth century. This weakening is revealed by a characteristic spatial and seasonal sea-surface temperature ‘fingerprint’—consisting of a pattern of cooling in the subpolar Atlantic Ocean and warming in the Gulf Stream region— and is calibrated through an ensemble of model simulations from the CMIP5 project. We find this fingerprint both in a high-resolution climate model in response to increasing atmospheric carbon dioxide concentrations, and in the temperature trends observed since the late nineteenth century. The pattern can be explained by a slowdown in the AMOC and reduced northward heat transport, as well as an associated northward shift of the Gulf Stream. Comparisons with recent direct measurements from the RAPID project and several other studies provide a consistent depiction of recordlow AMOC values in recent years.

    Item Type: Article
    Additional Information: Cite as: Caesar, L., Rahmstorf, S., Robinson, A. et al. Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature 556, 191–196 (2018). https://doi.org/10.1038/s41586-018-0006-5
    Keywords: Atlantic Ocean; overturning circulation; Climate and Earth system modelling; Ocean sciences; Physical oceanography;
    Academic Unit: Faculty of Social Sciences > Geography
    Faculty of Social Sciences > Research Institutes > Irish Climate Analysis and Research Units, ICARUS
    Item ID: 13174
    Identification Number: https://doi.org/10.1038/s41586-018-0006-5
    Depositing User: Levke Caesar
    Date Deposited: 07 Aug 2020 19:53
    Journal or Publication Title: Nature
    Publisher: Nature Research
    Refereed: Yes
    URI:

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