Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle
Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost mo...
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ftdoajarticles:oai:doaj.org/article:8a7fcf8ee1714646b8d9ff1d9d3e5282 2023-05-15T14:28:57+02:00 Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle M. Willeit A. Ganopolski 2015-09-01T00:00:00Z https://doi.org/10.5194/cp-11-1165-2015 https://doaj.org/article/8a7fcf8ee1714646b8d9ff1d9d3e5282 EN eng Copernicus Publications http://www.clim-past.net/11/1165/2015/cp-11-1165-2015.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-11-1165-2015 https://doaj.org/article/8a7fcf8ee1714646b8d9ff1d9d3e5282 Climate of the Past, Vol 11, Iss 9, Pp 1165-1180 (2015) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2015 ftdoajarticles https://doi.org/10.5194/cp-11-1165-2015 2023-01-08T01:25:27Z Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost–ice-sheet evolution over the last glacial cycle is explored. The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates. Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200–500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka. Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM. Article in Journal/Newspaper Arctic Archipelago Arctic Ice Ice Sheet permafrost Siberia Directory of Open Access Journals: DOAJ Articles Arctic Climate of the Past 11 9 1165 1180 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 M. Willeit A. Ganopolski Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Permafrost influences a number of processes which are relevant for local and global climate. For example, it is well known that permafrost plays an important role in global carbon and methane cycles. Less is known about the interaction between permafrost and ice sheets. In this study a permafrost module is included in the Earth system model CLIMBER-2, and the coupled Northern Hemisphere (NH) permafrost–ice-sheet evolution over the last glacial cycle is explored. The model performs generally well at reproducing present-day permafrost extent and thickness. Modeled permafrost thickness is sensitive to the values of ground porosity, thermal conductivity and geothermal heat flux. Permafrost extent at the Last Glacial Maximum (LGM) agrees well with reconstructions and previous modeling estimates. Present-day permafrost thickness is far from equilibrium over deep permafrost regions. Over central Siberia and the Arctic Archipelago permafrost is presently up to 200–500 m thicker than it would be at equilibrium. In these areas, present-day permafrost depth strongly depends on the past climate history and simulations indicate that deep permafrost has a memory of surface temperature variations going back to at least 800 ka. Over the last glacial cycle permafrost has a relatively modest impact on simulated NH ice sheet volume except at LGM, when including permafrost increases ice volume by about 15 m sea level equivalent in our model. This is explained by a delayed melting of the ice base from below by the geothermal heat flux when the ice sheet sits on a porous sediment layer and permafrost has to be melted first. Permafrost affects ice sheet dynamics only when ice extends over areas covered by thick sediments, which is the case at LGM. |
format |
Article in Journal/Newspaper |
author |
M. Willeit A. Ganopolski |
author_facet |
M. Willeit A. Ganopolski |
author_sort |
M. Willeit |
title |
Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
title_short |
Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
title_full |
Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
title_fullStr |
Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
title_full_unstemmed |
Coupled Northern Hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
title_sort |
coupled northern hemisphere permafrost–ice-sheet evolution over the last glacial cycle |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/cp-11-1165-2015 https://doaj.org/article/8a7fcf8ee1714646b8d9ff1d9d3e5282 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Archipelago Arctic Ice Ice Sheet permafrost Siberia |
genre_facet |
Arctic Archipelago Arctic Ice Ice Sheet permafrost Siberia |
op_source |
Climate of the Past, Vol 11, Iss 9, Pp 1165-1180 (2015) |
op_relation |
http://www.clim-past.net/11/1165/2015/cp-11-1165-2015.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-11-1165-2015 https://doaj.org/article/8a7fcf8ee1714646b8d9ff1d9d3e5282 |
op_doi |
https://doi.org/10.5194/cp-11-1165-2015 |
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Climate of the Past |
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11 |
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9 |
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1165 |
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1180 |
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