A simple equation for the melt elevation feedback of ice sheets
In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown...
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ftleibnizopen:oai:oai.leibnizopen.de:4C_SeYsBBwLIz6xGBOAh 2023-11-12T04:13:57+01:00 A simple equation for the melt elevation feedback of ice sheets Levermann, Anders Winkelmann, Ricarda 2016 application/pdf https://oa.tib.eu/renate/handle/123456789/8992 https://doi.org/10.34657/8030 eng eng Katlenburg-Lindau : European Geosciences Union CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ The Cryosphere 10 (2016), Nr. 4 air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet 550 article Text 2016 ftleibnizopen https://doi.org/10.34657/8030 2023-10-30T00:35:51Z In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown of the Greenland Ice Sheet is induced by the self-enforcing feedback between its lowering surface elevation and its increasing surface mass loss: the more ice that is lost, the lower the ice surface and the warmer the surface air temperature, which fosters further melting and ice loss. The computation of this rate so far relies on complex numerical models which are the appropriate tools for capturing the complexity of the problem. By contrast we aim here at gaining a conceptual understanding by deriving a purposefully simple equation for the self-enforcing feedback which is then used to estimate the melt time for different levels of warming using three observable characteristics of the ice sheet itself and its surroundings. The analysis is purely conceptual in nature. It is missing important processes like ice dynamics for it to be useful for applications to sea-level rise on centennial timescales, but if the volume loss is dominated by the feedback, the resulting logarithmic equation unifies existing numerical simulations and shows that the melt time depends strongly on the level of warming with a critical slowdown near the threshold: the median time to lose 10 % of the present-day ice volume varies between about 3500 years for a temperature level of 0.5 °C above the threshold and 500 years for 5 °C. Unless future observations show a significantly higher melting sensitivity than currently observed, a complete meltdown is unlikely within the next 2000 years without significant ice-dynamical contributions. publishedVersion Article in Journal/Newspaper Arctic Greenland Ice Sheet The Cryosphere Unknown |
institution |
Open Polar |
collection |
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op_collection_id |
ftleibnizopen |
language |
English |
topic |
air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet 550 |
spellingShingle |
air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet 550 Levermann, Anders Winkelmann, Ricarda A simple equation for the melt elevation feedback of ice sheets |
topic_facet |
air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet 550 |
description |
In recent decades, the Greenland Ice Sheet has been losing mass and has thereby contributed to global sea-level rise. The rate of ice loss is highly relevant for coastal protection worldwide. The ice loss is likely to increase under future warming. Beyond a critical temperature threshold, a meltdown of the Greenland Ice Sheet is induced by the self-enforcing feedback between its lowering surface elevation and its increasing surface mass loss: the more ice that is lost, the lower the ice surface and the warmer the surface air temperature, which fosters further melting and ice loss. The computation of this rate so far relies on complex numerical models which are the appropriate tools for capturing the complexity of the problem. By contrast we aim here at gaining a conceptual understanding by deriving a purposefully simple equation for the self-enforcing feedback which is then used to estimate the melt time for different levels of warming using three observable characteristics of the ice sheet itself and its surroundings. The analysis is purely conceptual in nature. It is missing important processes like ice dynamics for it to be useful for applications to sea-level rise on centennial timescales, but if the volume loss is dominated by the feedback, the resulting logarithmic equation unifies existing numerical simulations and shows that the melt time depends strongly on the level of warming with a critical slowdown near the threshold: the median time to lose 10 % of the present-day ice volume varies between about 3500 years for a temperature level of 0.5 °C above the threshold and 500 years for 5 °C. Unless future observations show a significantly higher melting sensitivity than currently observed, a complete meltdown is unlikely within the next 2000 years without significant ice-dynamical contributions. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Levermann, Anders Winkelmann, Ricarda |
author_facet |
Levermann, Anders Winkelmann, Ricarda |
author_sort |
Levermann, Anders |
title |
A simple equation for the melt elevation feedback of ice sheets |
title_short |
A simple equation for the melt elevation feedback of ice sheets |
title_full |
A simple equation for the melt elevation feedback of ice sheets |
title_fullStr |
A simple equation for the melt elevation feedback of ice sheets |
title_full_unstemmed |
A simple equation for the melt elevation feedback of ice sheets |
title_sort |
simple equation for the melt elevation feedback of ice sheets |
publisher |
Katlenburg-Lindau : European Geosciences Union |
publishDate |
2016 |
url |
https://oa.tib.eu/renate/handle/123456789/8992 https://doi.org/10.34657/8030 |
genre |
Arctic Greenland Ice Sheet The Cryosphere |
genre_facet |
Arctic Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere 10 (2016), Nr. 4 |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ |
op_doi |
https://doi.org/10.34657/8030 |
_version_ |
1782331721790783488 |