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| Titel |
Uncertainties in the modelled CO2 threshold for Antarctic glaciation |
| VerfasserIn |
E. Gasson, D. J. Lunt, R. DeConto, A. Goldner, M. Heinemann, M. Huber, A. N. LeGrande, D. Pollard, N. Sagoo, M. Siddall, A. Winguth, P. J. Valdes |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 10, no. 2 ; Nr. 10, no. 2 (2014-03-11), S.451-466 |
| Datensatznummer |
250116932
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| Publikation (Nr.) |
 copernicus.org/cp-10-451-2014.pdf |
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| Zusammenfassung |
| A frequently cited atmospheric CO2 threshold for the onset of Antarctic
glaciation of ~780 ppmv is based on the study of DeConto and Pollard (2003)
using an ice sheet model and the GENESIS climate model. Proxy records suggest
that atmospheric CO2 concentrations passed through this threshold across
the Eocene–Oligocene transition ~34 Ma. However, atmospheric CO2
concentrations may have been close to this threshold earlier than this
transition, which is used by some to suggest the possibility of Antarctic ice
sheets during the Eocene. Here we investigate the climate model dependency of
the threshold for Antarctic glaciation by performing offline ice sheet model
simulations using the climate from 7 different climate models with
Eocene boundary conditions (HadCM3L, CCSM3, CESM1.0, GENESIS, FAMOUS, ECHAM5
and GISS_ER). These climate simulations are sourced from a number of
independent studies, and as such the boundary conditions, which are poorly
constrained during the Eocene, are not identical between simulations. The
results of this study suggest that the atmospheric CO2 threshold for
Antarctic glaciation is highly dependent on the climate model used and the
climate model configuration. A large discrepancy between the climate model
and ice sheet model grids for some simulations leads to a strong sensitivity
to the lapse rate parameter. |
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