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

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Fogwill, C. J. ; Turney, C. S. M. ; Golledge, N. R. ; Etheridge, D. M. ; Rubino, M. ; Thornton, D. P. ; Baker, A. ; Woodward, J. ; Winter, K. ; van Ommen, T. D. ; Moy, A. D. ; Curran, M. A. J. ; Davies, S. M. ; Weber, M. E. ; Bird, M. I. ; Munksgaard, N. C. ; Menviel, L. ; Rootes, C. M. ; Ellis, B. ; Millman, H. ; Vohra, J. ; Rivera, A. ; Cooper, A. (2017)

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.
  • References (40)
    40 references, page 1 of 4

    1. Masson-Delmotte, V. et al. In Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (eds T.F. Stocker et al.) Ch. 5, 383-464 (Cambridge University Press, 2013).

    2. Weber, M. E. et al. Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature 510, 134-138, doi: 10.1038/nature13397 (2014).

    3. Church, J. A. et al. In Climate Change 2013: eTh Physical Science Basis. Contribution of Working Group I to the Fihft Assessment Report of the Intergovernmental Panel on Climate Change (eds T.F. Stocker et al.) Ch. 13, 1137-1216 (Cambridge University Press, 2013).

    4. Collins, M. et al. In Climate Change 2013: eTh Physical Science Basis. Contribution of Working Group I to the Fihft Assessment Report of the Intergovernmental Panel on Climate Change (eds T.F. Stocker et al.) Ch. 12, 1029-1136 (Cambridge University Press, 2013).

    5. Joughin, I., Smith, B. E. & Medley, B. Marine ice sheet collapse potentially under way for the wThaites Glacier Basin, West Antarctica. Science 344, 735-738 (2014).

    6. van Wijk, E. M. & Rintoul, S. R. Freshening drives contraction of Antarctic Bottom Water in the Australian Antarctic Basin. Geophysical Research Letters 41, 2013GL058921, doi:10.1002/2013gl058921 (2014).

    7. Jones, J. M. et al. Assessing recent trends in high-latitude Southern Hemisphere surface climate. Nature Clim. Change 6, 917-926, doi: 10.1038/nclimate3103 (2016).

    8. Golledge, N. R. et al. The multi-millennial Antarctic commitment to future sea-level rise. Nature 526, 421-425, doi: 10.1038/ nature15706 (2015).

    9. Anderson, R. F. et al. Wind-Driven Upwelling in the Southern Ocean and the Deglacial Rise in Atmospheric CO2. Science 323, 1443-1448, (2009).

    10. Marcott, S. A. et al. Centennial-scale changes in the global carbon cycle during the last deglaciation. Nature 514, 616-619 (2014).

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