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| Titel |
The effects of climate uncertainty on the stability of the Antarctic ice sheet during the mid-Pliocene warm period |
| VerfasserIn |
Jorge Bernales, Tonio Häfliger, Irina Rogozhina, Maik Thomas |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111904
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| Publikation (Nr.) |
 EGU/EGU2015-12052.pdf |
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| Zusammenfassung |
| The mid-Pliocene (3.15 to 2.85 million years before present) is the most recent period in
Earth’s history when temperatures and CO2 concentrations were sustainedly higher than
pre-industrial valuesÂ[1], representing an ideal interval for studying the climate system under
conditions similar to those projected for the end of this century. In these projections, the
response of the Antarctic ice sheet (AIS) remains uncertain, including areas generally
considered stable under a warming climate. Therefore, a better understanding of AIS’s
behaviour during periods like the mid-Pliocene will provide valuable information on
the potential vulnerability of the composite parts of the AIS in the future. For this
purpose, we have designed numerical experiments of the AIS dynamics during
the mid-Pliocene warm period using the continental-scale ice sheet-shelf model
SICOPOLISÂ[2]. To account for the uncertainties in the configuration of the AIS and
climate conditions prior to this period, we employ a wide range of initial ice sheet
configurations and climatologies, including modern observations, the results from the
Pliocene Model Intercomparison Project (PlioMIP) climate experimentsÂ[3], and
perturbations to single climatic fields, allowing us to assess the vulnerability of
different AIS sectors to specific forcing mechanisms. Our simulations show that the
West Antarctic ice sheet remains largely ice-free under the chosen range of climate
conditions, except for small portions grounded above sea level. On the contrary,
the East Antarctic ice sheet (EAIS) shows no signs of potential collapse, with an
ice loss over a few peripheral sectors largely compensated by an increase in ice
volume over the interior due to increased precipitation rates and surface temperatures
remaining well below the freezing point. Furthermore, our results contrast with existing
hypotheses that cast doubt on the stability of the EAIS during the mid-Pliocene warm
period.
References
[1]ÂÂÂCook, C. P., et al. Dynamic behaviour of the East Antarctic ice sheet during
Pliocene warmth. Nature Geoscience 6.9 (2013): 765-769.
[2]ÂÂÂSato, T., and Greve, R. Sensitivity experiments for the Antarctic ice sheet with
varied sub-ice-shelf melting rates. Annals of Glaciology 53.60 (2012): 221-228.
[3]ÂÂÂHaywood, A. M., et al. Large-scale features of Pliocene climate: results from
the Pliocene Model Intercomparison Project. Clim. Past 9 (2013): 191-209. |
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