Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination

C. J. Fogwill, C. S M Turney, N. R. Golledge, D. M. Etheridge, M. Rubino, D. P. Thornton, A. Baker, J. Woodward, K. Winter, T. D. Van Ommen, A. D. Moy, M. A J Curran, S. M. Davies, M. E. Weber, M. I. Bird, N. C. Munksgaard, L. Menviel, C. M. Rootes, B. Ellis, H. MillmanJ. Vohra, A. Rivera, A. Cooper

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    Abstract

    Reconstructing the dynamic response of the Antarctic ice sheets to warming during the Last Glacial Termination (LGT; 18,000-11,650 yrs ago) allows us to disentangle ice-climate feedbacks that are key to improving future projections. Whilst the sequence of events during this period is reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records, making it difficult to assess relationships between Antarctic ice-sheet (AIS) dynamics, climate change and sea level. Here we present results from a highly-resolved 'horizontal ice core' from the Weddell Sea Embayment, which records millennial-scale AIS dynamics across this extensive region. Counterintuitively, we find AIS mass-loss across the full duration of the Antarctic Cold Reversal (ACR; 14,600-12,700 yrs ago), with stabilisation during the subsequent millennia of atmospheric warming. Earth-system and ice-sheet modelling suggests these contrasting trends were likely Antarctic-wide, sustained by feedbacks amplified by the delivery of Circumpolar Deep Water onto the continental shelf. Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections. With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise.

    Original languageEnglish
    Article number39979
    Pages (from-to)1-10
    Number of pages10
    JournalScientific Reports
    Volume7
    DOIs
    Publication statusPublished - 5 Jan 2017

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