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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ftdoajarticles:oai:doaj.org/article:f3347e8f34824c09af84dc5611218d1d 2023-05-15T16:28:41+02:00 A simple equation for the melt elevation feedback of ice sheets A. Levermann R. Winkelmann 2016-08-01T00:00:00Z https://doi.org/10.5194/tc-10-1799-2016 https://doaj.org/article/f3347e8f34824c09af84dc5611218d1d EN eng Copernicus Publications http://www.the-cryosphere.net/10/1799/2016/tc-10-1799-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-1799-2016 https://doaj.org/article/f3347e8f34824c09af84dc5611218d1d The Cryosphere, Vol 10, Iss 4, Pp 1799-1807 (2016) Environmental sciences GE1-350 Geology QE1-996.5 article 2016 ftdoajarticles https://doi.org/10.5194/tc-10-1799-2016 2022-12-31T13:47:51Z 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. Article in Journal/Newspaper Greenland Ice Sheet The Cryosphere Directory of Open Access Journals: DOAJ Articles Greenland The Cryosphere 10 4 1799 1807 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 A. Levermann R. Winkelmann A simple equation for the melt elevation feedback of ice sheets |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 |
A. Levermann R. Winkelmann |
author_facet |
A. Levermann R. Winkelmann |
author_sort |
A. Levermann |
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 |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-1799-2016 https://doaj.org/article/f3347e8f34824c09af84dc5611218d1d |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet The Cryosphere |
genre_facet |
Greenland Ice Sheet The Cryosphere |
op_source |
The Cryosphere, Vol 10, Iss 4, Pp 1799-1807 (2016) |
op_relation |
http://www.the-cryosphere.net/10/1799/2016/tc-10-1799-2016.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-10-1799-2016 https://doaj.org/article/f3347e8f34824c09af84dc5611218d1d |
op_doi |
https://doi.org/10.5194/tc-10-1799-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
4 |
container_start_page |
1799 |
op_container_end_page |
1807 |
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1766018361803669504 |