Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model
We study the initiation of a Marinoan Snowball Earth (~635 million years before present) with the state-of-the-art atmosphere-ocean general circulation model ECHAM5/MPI-OM. This is the most sophisticated model ever applied to Snowball initiation. A comparison with a pre-industrial control climate sh...
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ftcopernicus:oai:publications.copernicus.org:cp8818 2023-05-15T18:17:44+02:00 Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model Voigt, A. Abbot, D. S. Pierrehumbert, R. T. Marotzke, J. 2018-09-27 application/pdf https://doi.org/10.5194/cp-7-249-2011 https://cp.copernicus.org/articles/7/249/2011/ eng eng doi:10.5194/cp-7-249-2011 https://cp.copernicus.org/articles/7/249/2011/ eISSN: 1814-9332 Text 2018 ftcopernicus https://doi.org/10.5194/cp-7-249-2011 2020-07-20T16:26:11Z We study the initiation of a Marinoan Snowball Earth (~635 million years before present) with the state-of-the-art atmosphere-ocean general circulation model ECHAM5/MPI-OM. This is the most sophisticated model ever applied to Snowball initiation. A comparison with a pre-industrial control climate shows that the change of surface boundary conditions from present-day to Marinoan, including a shift of continents to low latitudes, induces a global-mean cooling of 4.6 K. Two thirds of this cooling can be attributed to increased planetary albedo, the remaining one third to a weaker greenhouse effect. The Marinoan Snowball Earth bifurcation point for pre-industrial atmospheric carbon dioxide is between 95.5 and 96% of the present-day total solar irradiance (TSI), whereas a previous study with the same model found that it was between 91 and 94% for present-day surface boundary conditions. A Snowball Earth for TSI set to its Marinoan value (94% of the present-day TSI) is prevented by doubling carbon dioxide with respect to its pre-industrial level. A zero-dimensional energy balance model is used to predict the Snowball Earth bifurcation point from only the equilibrium global-mean ocean potential temperature for present-day TSI. We do not find stable states with sea-ice cover above 55%, and land conditions are such that glaciers could not grow with sea-ice cover of 55%. Therefore, none of our simulations qualifies as a "slushball" solution. While uncertainties in important processes and parameters such as clouds and sea-ice albedo suggest that the Snowball Earth bifurcation point differs between climate models, our results contradict previous findings that Snowball Earth initiation would require much stronger forcings. Text Sea ice Copernicus Publications: E-Journals Climate of the Past 7 1 249 263 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
We study the initiation of a Marinoan Snowball Earth (~635 million years before present) with the state-of-the-art atmosphere-ocean general circulation model ECHAM5/MPI-OM. This is the most sophisticated model ever applied to Snowball initiation. A comparison with a pre-industrial control climate shows that the change of surface boundary conditions from present-day to Marinoan, including a shift of continents to low latitudes, induces a global-mean cooling of 4.6 K. Two thirds of this cooling can be attributed to increased planetary albedo, the remaining one third to a weaker greenhouse effect. The Marinoan Snowball Earth bifurcation point for pre-industrial atmospheric carbon dioxide is between 95.5 and 96% of the present-day total solar irradiance (TSI), whereas a previous study with the same model found that it was between 91 and 94% for present-day surface boundary conditions. A Snowball Earth for TSI set to its Marinoan value (94% of the present-day TSI) is prevented by doubling carbon dioxide with respect to its pre-industrial level. A zero-dimensional energy balance model is used to predict the Snowball Earth bifurcation point from only the equilibrium global-mean ocean potential temperature for present-day TSI. We do not find stable states with sea-ice cover above 55%, and land conditions are such that glaciers could not grow with sea-ice cover of 55%. Therefore, none of our simulations qualifies as a "slushball" solution. While uncertainties in important processes and parameters such as clouds and sea-ice albedo suggest that the Snowball Earth bifurcation point differs between climate models, our results contradict previous findings that Snowball Earth initiation would require much stronger forcings. |
format |
Text |
author |
Voigt, A. Abbot, D. S. Pierrehumbert, R. T. Marotzke, J. |
spellingShingle |
Voigt, A. Abbot, D. S. Pierrehumbert, R. T. Marotzke, J. Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
author_facet |
Voigt, A. Abbot, D. S. Pierrehumbert, R. T. Marotzke, J. |
author_sort |
Voigt, A. |
title |
Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
title_short |
Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
title_full |
Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
title_fullStr |
Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
title_full_unstemmed |
Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model |
title_sort |
initiation of a marinoan snowball earth in a state-of-the-art atmosphere-ocean general circulation model |
publishDate |
2018 |
url |
https://doi.org/10.5194/cp-7-249-2011 https://cp.copernicus.org/articles/7/249/2011/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-7-249-2011 https://cp.copernicus.org/articles/7/249/2011/ |
op_doi |
https://doi.org/10.5194/cp-7-249-2011 |
container_title |
Climate of the Past |
container_volume |
7 |
container_issue |
1 |
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249 |
op_container_end_page |
263 |
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1766192746377248768 |