Interaction between ocean circulation and ice margin dynamics in central west Greenland during the Holocene
Abstract
Since the mid-1990s acceleration, thinning and retreat of major tidewater glaciers draining the Greenland Ice Sheet has been recorded. This behaviour may record the response of critical sectors of the cryosphere to recent climate changes and suggests the ice sheet responds more quickly than previously thought. Such response could have important implications for sea-level change and ocean circulation. The critical link between climate change and ice dynamics is still unclear, though atmospheric warming and/or oceanic warming have been suggested as possible mechanisms driving the recent changes. Recent research by Holland et al. (2008) demonstrated that the acceleration and collapse of Jakobshavns Isbrae (a major west Greenland ice stream) coincided with the arrival of warmer subsurface waters, enhancing basal melting at the ice terminus. Our understanding of how ice sheets grounded below sea level may respond to future atmospheric and oceanic warming as well as rising sea-level is also rather limited. Investigating the Holocene oceanographic conditions on the shelf of west Greenland close to the marine-based ice allows us to investigate important controls on ice stream and ice sheet behaviour. It also provides a longer term context for the recent rapid changes. Here we present benthic foraminiferal data from a series of cores from the central west Greenland margin. These cores document the variability of the inflowing warm Atlantic sourced waters during the late Holocene. In particular we identify a clear cooling trend in ocean conditions over the last 2.5 ka. Superimposed on this longer term trend are centennial scale fluctuations in oceanic conditions linked to broader scale North Atlantic climate changes. We also provide records of variability in relative warmth of Atlantic water reaching west Greenland over the last century. Ocean warming over this timescale shows a good correlation with the historical evidence of ice stream stability and also more broadly with the Atlantic Multidecadal Oscillation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C23C0501L
- Keywords:
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- 0730 CRYOSPHERE / Ice streams;
- 4926 PALEOCEANOGRAPHY / Glacial