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| Titel |
Large-scale interaction between ice sheets and climate during the past 800,000 years |
| VerfasserIn |
Lennert Stap, Roderik van de Wal, Bas De Boer, Richard Bintanja, Lucas Lourens |
| 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 |
250091531
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| Publikation (Nr.) |
 EGU/EGU2014-5831.pdf |
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| Zusammenfassung |
| During the Cenozoic, land ice and climate have interacted on many different time scales. On
long time scales, the effect of land ice on global climate and sea level is dictated by large ice
sheets on North America, Eurasia, Greenland and Antarctica. The climatic forcing of ice
sheets is largely determined by the meridional temperature profile. In their turn, the ice sheets
cause an increase in albedo and surface elevation which affects the climate system. To
quantify the importance of these climate-land ice processes, a zonally-averaged energy
balance climate model is coupled to a one-dimensional ice-sheet model of the four
major ice sheets. The benefit of using relatively simple models is that the tested
model parameters are easily interpretable. Moreover, the shorter computation time
allows for more tests and long transient simulations at geological time scales to be
performed. This study focusses on the past 800,000 years, where a high-confidence
CO2-record from ice-core samples is used as input. Simulations of atmospheric
temperature, ice volume and sea level are obtained, that are in good agreement with recent
proxy-data reconstructions (RMSE=20 m over the last glacial cycle). The climate-ice
sheet interaction is studied by a comparison of simulations with uncoupled and
coupled ice sheets. By performing runs with CO2 or insolation held constant, the
influence of these variables is assessed. It is found that atmospheric temperature is
controlled by a complex interaction of CO2 and insolation. Finally, we show that the
amplification of the climate sensitivity from the long-term ice feedback is a factor 3. |
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