Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation

M. E. Weber, P. U. Clark, G. Kuhn, A. Timmermann, D. Sprenk, R. Gladstone, X. Zhang, G. Lohmann, L. Menviel, M. O. Chikamoto, T. Friedrich, C. Ohlwein

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

Our understanding of the deglacial evolution of the Antarctic Ice Sheet (AIS) following the Last Glacial Maximum (26,000-19,000 years ago) is based largely on a few well-dated but temporally and geographically restricted terrestrial and shallow-marine sequences. This sparseness limits our understanding of the dominant feedbacks between the AIS, Southern Hemisphere climate and global sea level. Marine records of iceberg-rafted debris (IBRD) provide a nearly continuous signal of ice-sheet dynamics and variability. IBRD records from the North Atlantic Ocean have been widely used to reconstruct variability in Northern Hemisphere ice sheets, but comparable records from the Southern Ocean of the AIS are lacking because of the low resolution and large dating uncertainties in existing sediment cores. Here we present two well-dated, high-resolution IBRD records that capture a spatially integrated signal of AIS variability during the last deglaciation. We document eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago, in marked contrast to previous scenarios which identified the main AIS retreat as occurring after meltwater pulse 1A and continuing into the late Holocene epoch. The highest IBRD flux occurred 14,600 years ago, providing the first direct evidence for an Antarctic contribution to meltwater pulse 1A. Climate model simulations with AIS freshwater forcing identify a positive feedback between poleward transport of Circumpolar Deep Water, subsurface warming and AIS melt, suggesting that small perturbations to the ice sheet can be substantially enhanced, providing a possible mechanism for rapid sea-level rise.

LanguageEnglish
Pages134-138
Number of pages5
JournalNature
Volume510
Issue number7503
Early online date28 May 2014
DOIs
Publication statusPublished - 5 Jun 2014

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last deglaciation
ice sheet
iceberg
meltwater
marine record
Last Glacial Maximum
sediment core
Southern Hemisphere
climate modeling
Northern Hemisphere
deep water
warming
perturbation
Holocene
melt
sea level

Cite this

Weber, M. E., Clark, P. U., Kuhn, G., Timmermann, A., Sprenk, D., Gladstone, R., ... Ohlwein, C. (2014). Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature, 510(7503), 134-138. https://doi.org/10.1038/nature13397
Weber, M. E. ; Clark, P. U. ; Kuhn, G. ; Timmermann, A. ; Sprenk, D. ; Gladstone, R. ; Zhang, X. ; Lohmann, G. ; Menviel, L. ; Chikamoto, M. O. ; Friedrich, T. ; Ohlwein, C. / Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. In: Nature. 2014 ; Vol. 510, No. 7503. pp. 134-138.
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Weber, ME, Clark, PU, Kuhn, G, Timmermann, A, Sprenk, D, Gladstone, R, Zhang, X, Lohmann, G, Menviel, L, Chikamoto, MO, Friedrich, T & Ohlwein, C 2014, 'Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation', Nature, vol. 510, no. 7503, pp. 134-138. https://doi.org/10.1038/nature13397

Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. / Weber, M. E.; Clark, P. U.; Kuhn, G.; Timmermann, A.; Sprenk, D.; Gladstone, R.; Zhang, X.; Lohmann, G.; Menviel, L.; Chikamoto, M. O.; Friedrich, T.; Ohlwein, C.

In: Nature, Vol. 510, No. 7503, 05.06.2014, p. 134-138.

Research output: Contribution to journalArticle

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AU - Ohlwein, C.

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Weber ME, Clark PU, Kuhn G, Timmermann A, Sprenk D, Gladstone R et al. Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation. Nature. 2014 Jun 5;510(7503):134-138. https://doi.org/10.1038/nature13397