Rapid early Holocene deglaciation of the Laurentide ice sheet
Date
2008-07-24Author
Carlson, Anders E.
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LeGrande, Allegra N.
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Oppo, Delia W.
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Came, Rosemarie E.
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Schmidt, Gavin A.
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Anslow, Faron S.
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Licciardi, Joseph M.
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Obbink, Elizabeth A.
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https://hdl.handle.net/1912/2707As published
https://doi.org/10.1038/ngeo285Abstract
The early Holocene deglaciation of the Laurentide Ice Sheet (LIS) is the most recent
and best constrained disappearance of a large Northern Hemisphere ice sheet. Its
demise is a natural experiment for assessing rates of ice sheet decay and attendant
contributions to sea level rise. Here we demonstrate with terrestrial and marine
records that the final LIS demise occurred in two stages of rapid melting from ~9.0-
8.5 and 7.6-6.8 kyr BP with the LIS contributing ~1.3 and 0.7 cm yr-1 to sea level
rise, respectively. Simulations using a fully coupled atmosphere-ocean general
circulation model suggest that increased ablation from enhanced early Holocene
boreal summer insolation may have been the predominant cause of the LIS
contributions to sea level rise. Although the boreal summer surface radiative
forcing of early Holocene LIS retreat is twice that of projections for 2100 C.E.
greenhouse gas radiative forcing, the associated summer surface air temperature
increase is the same. The geologic evidence for rapid LIS retreat under a
comparable forcing provides a prehistoric precedent for a possible large negative
mass balance response of the Greenland Ice Sheet by the end of the coming century.
Description
Author Posting. © Nature Publishing Group, 2008. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Geoscience 1 (2008): 620-624, doi:10.1038/ngeo285.