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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fttibhannoverren:oai:oa.tib.eu:123456789/8992 2024-09-15T18:09:06+00:00 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 ESSN:1994-0424 DOI:https://doi.org/10.5194/tc-10-1799-2016 https://oa.tib.eu/renate/handle/123456789/8992 https://doi.org/10.34657/8030 CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich ddc:550 air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet status-type:publishedVersion doc-type:Article doc-type:Text 2016 fttibhannoverren https://doi.org/10.34657/803010.5194/tc-10-1799-2016 2024-07-03T23:33:53Z 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. Article in Journal/Newspaper Greenland Ice Sheet Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
institution |
Open Polar |
collection |
Renate - Repositorium für Naturwissenschaften und Technik (TIB Hannover) |
op_collection_id |
fttibhannoverren |
language |
English |
topic |
ddc:550 air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet |
spellingShingle |
ddc:550 air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet Levermann, Anders Winkelmann, Ricarda A simple equation for the melt elevation feedback of ice sheets |
topic_facet |
ddc:550 air temperature elevation feedback mechanism ice sheet mass balance melt numerical model sea level change threshold warming Arctic Greenland Greenland Ice Sheet |
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. |
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 |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_relation |
ESSN:1994-0424 DOI:https://doi.org/10.5194/tc-10-1799-2016 https://oa.tib.eu/renate/handle/123456789/8992 https://doi.org/10.34657/8030 |
op_rights |
CC BY 3.0 Unported https://creativecommons.org/licenses/by/3.0/ frei zugänglich |
op_doi |
https://doi.org/10.34657/803010.5194/tc-10-1799-2016 |
_version_ |
1810446493905059840 |