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| Titel |
Model reconstruction of CO2 over the past five million years |
| VerfasserIn |
Lennert Stap, Bas De Boer, Martin Ziegler, Richard Bintanja, Lucas Lourens, Roderik van de Wal |
| 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 |
250105831
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| Publikation (Nr.) |
 EGU/EGU2015-5416.pdf |
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| Zusammenfassung |
| Over the past five million years, climates ranged from warmer than today during the Pliocene
Warm Period to considerably colder during glacials. Proxy data on sea level and
CO2 in the pre-ice core period, however, are scarce and intermittent. This hampers
understanding of the long-term relations between these variables and the climate.
This study focuses on reconciling knowledge on benthic δ18O, CO2, sea level
and climate, using a fully coupled climate-ice sheet model, inversely forced by
a stacked benthic δ18O record. We obtain the first continuous five-million-year
record of CO2, mutually consistent with sea level and temperature. During the
Pliocene, we simulate significantly higher CO2 levels than during the Pleistocene. A
compilation of existing δ11B-based proxy CO2 data and a new δ11B data record
provide support for this result. In our model, limited variability of ice volume reduces
ice sheet-climate feedbacks during this time. As a result, CO2 changes need to
be larger to obtain similar temperature changes as during the Pleistocene. This
indicates a changing relation between CO2 and temperature over time. However, while
increasing the ablation rate on the East Antarctic ice sheet results in larger sea level
fluctuations, it only modestly affects the simulated CO2. This is explained by the
surface albedo change being limited if the Antarctic ice sheet retreats during the
Pliocene, because the exposed land remains snow covered throughout most of the year. |
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