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Nat Commun. 2014 Sep 29;5:5107. doi: 10.1038/ncomms6107.

Antarctic contribution to meltwater pulse 1A from reduced Southern Ocean overturning.

Author information

1
1] Antarctic Research Centre, Victoria University of Wellington, Wellington 6140, New Zealand [2] GNS Science, Avalon, Lower Hutt 5011, New Zealand.
2
1] Climate Change Research Centre, University of New South Wales, Sydney, New South Wales 2052, Australia [2] ARC Centre of Excellence for Climate System Science, Sydney, New South Wales 2052, Australia.
3
Antarctic Research Centre, Victoria University of Wellington, Wellington 6140, New Zealand.
4
Climate Change Research Centre, University of New South Wales, Sydney, New South Wales 2052, Australia.
5
GNS Science, Avalon, Lower Hutt 5011, New Zealand.

Abstract

During the last glacial termination, the upwelling strength of the southern polar limb of the Atlantic Meridional Overturning Circulation varied, changing the ventilation and stratification of the high-latitude Southern Ocean. During the same period, at least two phases of abrupt global sea-level rise--meltwater pulses--took place. Although the timing and magnitude of these events have become better constrained, a causal link between ocean stratification, the meltwater pulses and accelerated ice loss from Antarctica has not been proven. Here we simulate Antarctic ice sheet evolution over the last 25‚ÄČkyr using a data-constrained ice-sheet model forced by changes in Southern Ocean temperature from an Earth system model. Results reveal several episodes of accelerated ice-sheet recession, the largest being coincident with meltwater pulse 1A. This resulted from reduced Southern Ocean overturning following Heinrich Event 1, when warmer subsurface water thermally eroded grounded marine-based ice and instigated a positive feedback that further accelerated ice-sheet retreat.

PMID:
25263015
DOI:
10.1038/ncomms6107

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