Uncertainties in the modelled CO2 threshold for Antarctic glaciation

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

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Abstract

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.

Original languageEnglish (US)
Pages (from-to)451-466
Number of pages16
JournalClimate of the Past
Volume10
Issue number2
DOIs
StatePublished - Mar 11 2014

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glaciation
climate modeling
ice sheet
Eocene
simulation
boundary condition
climate
Oligocene

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Stratigraphy
  • Palaeontology

Cite this

Gasson, E., Lunt, D. J., Deconto, R., Goldner, A., Heinemann, M., Huber, M., ... Valdes, P. J. (2014). Uncertainties in the modelled CO2 threshold for Antarctic glaciation. Climate of the Past, 10(2), 451-466. https://doi.org/10.5194/cp-10-451-2014
Gasson, E. ; Lunt, D. J. ; Deconto, R. ; Goldner, A. ; Heinemann, M. ; Huber, M. ; Legrande, A. N. ; Pollard, D. ; Sagoo, N. ; Siddall, M. ; Winguth, A. ; Valdes, P. J. / Uncertainties in the modelled CO2 threshold for Antarctic glaciation. In: Climate of the Past. 2014 ; Vol. 10, No. 2. pp. 451-466.
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Gasson, E, Lunt, DJ, Deconto, R, Goldner, A, Heinemann, M, Huber, M, Legrande, AN, Pollard, D, Sagoo, N, Siddall, M, Winguth, A & Valdes, PJ 2014, 'Uncertainties in the modelled CO2 threshold for Antarctic glaciation', Climate of the Past, vol. 10, no. 2, pp. 451-466. https://doi.org/10.5194/cp-10-451-2014

Uncertainties in the modelled CO2 threshold for Antarctic glaciation. / Gasson, E.; Lunt, D. J.; Deconto, R.; Goldner, A.; Heinemann, M.; Huber, M.; Legrande, A. N.; Pollard, D.; Sagoo, N.; Siddall, M.; Winguth, A.; Valdes, P. J.

In: Climate of the Past, Vol. 10, No. 2, 11.03.2014, p. 451-466.

Research output: Contribution to journalArticle

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Gasson E, Lunt DJ, Deconto R, Goldner A, Heinemann M, Huber M et al. Uncertainties in the modelled CO2 threshold for Antarctic glaciation. Climate of the Past. 2014 Mar 11;10(2):451-466. https://doi.org/10.5194/cp-10-451-2014