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...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-03-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/7/249/2011/cp-7-249-2011.pdf |
| _version_ | 1818540914584322048 |
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| author | A. Voigt D. S. Abbot R. T. Pierrehumbert J. Marotzke |
| author_facet | A. Voigt D. S. Abbot R. T. Pierrehumbert J. Marotzke |
| author_sort | A. Voigt |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-12-11T22:01:39Z |
| format | Article |
| id | doaj.art-5ae7c52931e34e99b7d666fe5bafe6ce |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-11T22:01:39Z |
| publishDate | 2011-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-5ae7c52931e34e99b7d666fe5bafe6ce2022-12-22T00:49:06ZengCopernicus PublicationsClimate of the Past1814-93241814-93322011-03-017124926310.5194/cp-7-249-2011Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation modelA. VoigtD. S. AbbotR. T. PierrehumbertJ. MarotzkeWe 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.http://www.clim-past.net/7/249/2011/cp-7-249-2011.pdf |
| spellingShingle | A. Voigt D. S. Abbot R. T. Pierrehumbert J. Marotzke Initiation of a Marinoan Snowball Earth in a state-of-the-art atmosphere-ocean general circulation model Climate of the Past |
| title | 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_short | 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 |
| url | http://www.clim-past.net/7/249/2011/cp-7-249-2011.pdf |
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