Large and irreversible future decline of the Greenland ice sheet
We have studied the evolution of the Greenland ice sheet under a range of constant climates typical of those projected for the end of the present century using a dynamical ice sheet model (Glimmer) coupled to an atmosphere general circulation model (FAMOUS–ice AGCM). The ice sheet surface mass balan...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:ab1ec347c85b49ddac7255e2d48fa164 2023-05-15T16:28:57+02:00 Large and irreversible future decline of the Greenland ice sheet J. M. Gregory S. E. George R. S. Smith 2020-12-01 https://doi.org/10.5194/tc-14-4299-2020 https://tc.copernicus.org/articles/14/4299/2020/tc-14-4299-2020.pdf https://doaj.org/article/ab1ec347c85b49ddac7255e2d48fa164 en eng Copernicus Publications doi:10.5194/tc-14-4299-2020 1994-0416 1994-0424 https://tc.copernicus.org/articles/14/4299/2020/tc-14-4299-2020.pdf https://doaj.org/article/ab1ec347c85b49ddac7255e2d48fa164 undefined The Cryosphere, Vol 14, Pp 4299-4322 (2020) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2020 fttriple https://doi.org/10.5194/tc-14-4299-2020 2023-01-22T18:11:06Z We have studied the evolution of the Greenland ice sheet under a range of constant climates typical of those projected for the end of the present century using a dynamical ice sheet model (Glimmer) coupled to an atmosphere general circulation model (FAMOUS–ice AGCM). The ice sheet surface mass balance (SMB) is simulated within the AGCM by a multilayer snow scheme from snowfall and surface energy fluxes, including refreezing and dependence on altitude within AGCM grid boxes. Over millennia under any warmer climate, the ice sheet reaches a new steady state, whose mass is correlated with the magnitude of global climate change imposed. If a climate that gives the recently observed SMB were maintained, global-mean sea level rise (GMSLR) would reach 0.5–2.5 m. For any global warming exceeding 3 K, the contribution to GMSLR exceeds 5 m. For the largest global warming considered (about +5 K), the rate of GMSLR is initially 2.7 mm yr−1, and eventually only a small ice cap endures, resulting in over 7 m of GMSLR. Our analysis gives a qualitatively different impression from previous work in that we do not find a sharp threshold warming that divides scenarios in which the ice sheet suffers little reduction from those in which it is mostly lost. The final steady state is achieved by withdrawal from the coast in some places and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice sheet by the effects of topographic change on atmospheric circulation, outweighing the tendency for decreasing SMB from the reduction in surface altitude. If late 20th-century climate is restored after the ice sheet mass has fallen below a threshold of about 4 m of sea level equivalent, it will not regrow to its present extent because the snowfall in the northern part of the island is reduced once the ice sheet retreats from there. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice sheet has declined to ... Article in Journal/Newspaper Greenland Ice cap Ice Sheet The Cryosphere Unknown Greenland The Cryosphere 14 12 4299 4322 |
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geo envir J. M. Gregory S. E. George R. S. Smith Large and irreversible future decline of the Greenland ice sheet |
topic_facet |
geo envir |
description |
We have studied the evolution of the Greenland ice sheet under a range of constant climates typical of those projected for the end of the present century using a dynamical ice sheet model (Glimmer) coupled to an atmosphere general circulation model (FAMOUS–ice AGCM). The ice sheet surface mass balance (SMB) is simulated within the AGCM by a multilayer snow scheme from snowfall and surface energy fluxes, including refreezing and dependence on altitude within AGCM grid boxes. Over millennia under any warmer climate, the ice sheet reaches a new steady state, whose mass is correlated with the magnitude of global climate change imposed. If a climate that gives the recently observed SMB were maintained, global-mean sea level rise (GMSLR) would reach 0.5–2.5 m. For any global warming exceeding 3 K, the contribution to GMSLR exceeds 5 m. For the largest global warming considered (about +5 K), the rate of GMSLR is initially 2.7 mm yr−1, and eventually only a small ice cap endures, resulting in over 7 m of GMSLR. Our analysis gives a qualitatively different impression from previous work in that we do not find a sharp threshold warming that divides scenarios in which the ice sheet suffers little reduction from those in which it is mostly lost. The final steady state is achieved by withdrawal from the coast in some places and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice sheet by the effects of topographic change on atmospheric circulation, outweighing the tendency for decreasing SMB from the reduction in surface altitude. If late 20th-century climate is restored after the ice sheet mass has fallen below a threshold of about 4 m of sea level equivalent, it will not regrow to its present extent because the snowfall in the northern part of the island is reduced once the ice sheet retreats from there. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice sheet has declined to ... |
format |
Article in Journal/Newspaper |
author |
J. M. Gregory S. E. George R. S. Smith |
author_facet |
J. M. Gregory S. E. George R. S. Smith |
author_sort |
J. M. Gregory |
title |
Large and irreversible future decline of the Greenland ice sheet |
title_short |
Large and irreversible future decline of the Greenland ice sheet |
title_full |
Large and irreversible future decline of the Greenland ice sheet |
title_fullStr |
Large and irreversible future decline of the Greenland ice sheet |
title_full_unstemmed |
Large and irreversible future decline of the Greenland ice sheet |
title_sort |
large and irreversible future decline of the greenland ice sheet |
publisher |
Copernicus Publications |
publishDate |
2020 |
url |
https://doi.org/10.5194/tc-14-4299-2020 https://tc.copernicus.org/articles/14/4299/2020/tc-14-4299-2020.pdf https://doaj.org/article/ab1ec347c85b49ddac7255e2d48fa164 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice cap Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice cap Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 14, Pp 4299-4322 (2020) |
op_relation |
doi:10.5194/tc-14-4299-2020 1994-0416 1994-0424 https://tc.copernicus.org/articles/14/4299/2020/tc-14-4299-2020.pdf https://doaj.org/article/ab1ec347c85b49ddac7255e2d48fa164 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-14-4299-2020 |
container_title |
The Cryosphere |
container_volume |
14 |
container_issue |
12 |
container_start_page |
4299 |
op_container_end_page |
4322 |
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