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| Titel |
Mechanisms producing warm-climate ice retreat in East Antarctic subglacial basins |
| VerfasserIn |
David Pollard, Robert DeConto |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096072
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| Publikation (Nr.) |
 EGU/EGU2014-11556.pdf |
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| Zusammenfassung |
| Geological data indicate that global sea level has fluctuated
on O(10,000) to O(1,000,000) year time scales during the last
~25 million years. Peak levels are uncertain, but some estimates
suggest high stands of ~20 m or more above modern, for instance
during the mid Pliocene. If correct, this implies substantial
variations in the size of the East Antarctic Ice Sheet (EAIS).
However, climate and ice-sheet models have not been able to
simulate significant EAIS retreat from continental size, given
low proxy atmospheric CO2 levels during this time. Here, we use
a continental Antarctic ice-sheet model with two new mechanisms
based on previous studies and observations: (1) structural failure
of large tidewater ice cliffs, and (2) enhanced ice-shelf calving
due to meltwater drainage into crevasses.
With atmospheric and oceanic forcing representing Pliocene warm
periods, the new mechanisms greatly accelerate the expected
collapse of marine ice in West Antarctica, and also cause drastic
retreat into 3 major East Antarctic subglacial basins, producing
~15 m global sea-level rise within a few thousand years. Basic
results are presented, along with details of the cliff-failure
numerics, and a simple parameterization of the clogging effects
of ice melange in narrow seaways, which aids in ice-sheet
recovery after colder climates resume. |
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