Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded
Observations of ocean-driven grounding line retreat in the Amundsen Sea Embayment in Antarctica give rise to the question of a collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under present-day climate conditions to locate the underlying...
Main Authors: | , , , , , , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2023
|
Subjects: | |
Online Access: | http://hdl.handle.net/21.11116/0000-000D-AB7A-A http://hdl.handle.net/21.11116/0000-000D-E92F-9 http://hdl.handle.net/21.11116/0000-000D-E930-6 |
id |
ftpubman:oai:pure.mpg.de:item_3528597 |
---|---|
record_format |
openpolar |
spelling |
ftpubman:oai:pure.mpg.de:item_3528597 2023-12-17T10:18:21+01:00 Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded The stability of present-day Antarctic grounding lines - Part 2 Possible commitment of regional collapse under current climate Reese, R. Garbe, J. Hill, E. Urruty, B. Naughten, K. Gagliardini, O. Durand, G. Gillet-Chaulet, F. Chandler, D. Langebroek, P. Winkelmann, R. 2023-09 application/pdf http://hdl.handle.net/21.11116/0000-000D-AB7A-A http://hdl.handle.net/21.11116/0000-000D-E92F-9 http://hdl.handle.net/21.11116/0000-000D-E930-6 eng eng info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-17-3761-2023 info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-2022-105 http://hdl.handle.net/21.11116/0000-000D-AB7A-A http://hdl.handle.net/21.11116/0000-000D-E92F-9 http://hdl.handle.net/21.11116/0000-000D-E930-6 info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/ The Cryosphere info:eu-repo/semantics/article 2023 ftpubman https://doi.org/10.5194/tc-17-3761-202310.5194/tc-2022-105 2023-11-20T00:47:10Z Observations of ocean-driven grounding line retreat in the Amundsen Sea Embayment in Antarctica give rise to the question of a collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under present-day climate conditions to locate the underlying steady states that they are attracted to and understand the reversibility of large-scale changes. To this aim, we first calibrate the sub-shelf melt module PICO with observed and modelled melt sensitivities to ocean temperature changes. Using the new calibration, we run an ensemble of historical simulations from 1850 to 2015 with the Parallel Ice Sheet Model to create model instances of possible present-day ice sheet configurations. Then, we extend a subset of simulations best representing the present-day ice sheet for another 10,000 years to investigate their evolution under constant present-day climate forcing. We test for reversibility of grounding line movement if large-scale retreat occurs. While we find parameter combinations for which no retreat happens in the Amundsen Sea Embayment sector, we also find admissible model parameters for which an irreversible retreat takes place. Hence, it cannot be ruled out that the grounding lines – which are not engaged in an irreversible retreat at the moment as shown in our companion paper (Part A, Urruty et al., subm.) – will evolve towards such a retreat under current climate conditions. Importantly, an irreversible collapse in the Amundsen Sea Embayment sector evolves on millennial timescales and is not inevitable yet, but could become so if forcing on the climate system is not reduced in the future. In contrast, we find that allowing ice shelves to regrow to their present geometry means that large-scale grounding line retreat into marine basins upstream of Filchner-Ronne and Ross ice shelves is reversible. Other grounding lines remain close to their current positions in all configurations under present-day climate. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Ice Shelves The Cryosphere Max Planck Society: MPG.PuRe Amundsen Sea Antarctic West Antarctic Ice Sheet |
institution |
Open Polar |
collection |
Max Planck Society: MPG.PuRe |
op_collection_id |
ftpubman |
language |
English |
description |
Observations of ocean-driven grounding line retreat in the Amundsen Sea Embayment in Antarctica give rise to the question of a collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under present-day climate conditions to locate the underlying steady states that they are attracted to and understand the reversibility of large-scale changes. To this aim, we first calibrate the sub-shelf melt module PICO with observed and modelled melt sensitivities to ocean temperature changes. Using the new calibration, we run an ensemble of historical simulations from 1850 to 2015 with the Parallel Ice Sheet Model to create model instances of possible present-day ice sheet configurations. Then, we extend a subset of simulations best representing the present-day ice sheet for another 10,000 years to investigate their evolution under constant present-day climate forcing. We test for reversibility of grounding line movement if large-scale retreat occurs. While we find parameter combinations for which no retreat happens in the Amundsen Sea Embayment sector, we also find admissible model parameters for which an irreversible retreat takes place. Hence, it cannot be ruled out that the grounding lines – which are not engaged in an irreversible retreat at the moment as shown in our companion paper (Part A, Urruty et al., subm.) – will evolve towards such a retreat under current climate conditions. Importantly, an irreversible collapse in the Amundsen Sea Embayment sector evolves on millennial timescales and is not inevitable yet, but could become so if forcing on the climate system is not reduced in the future. In contrast, we find that allowing ice shelves to regrow to their present geometry means that large-scale grounding line retreat into marine basins upstream of Filchner-Ronne and Ross ice shelves is reversible. Other grounding lines remain close to their current positions in all configurations under present-day climate. |
format |
Article in Journal/Newspaper |
author |
Reese, R. Garbe, J. Hill, E. Urruty, B. Naughten, K. Gagliardini, O. Durand, G. Gillet-Chaulet, F. Chandler, D. Langebroek, P. Winkelmann, R. |
spellingShingle |
Reese, R. Garbe, J. Hill, E. Urruty, B. Naughten, K. Gagliardini, O. Durand, G. Gillet-Chaulet, F. Chandler, D. Langebroek, P. Winkelmann, R. Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
author_facet |
Reese, R. Garbe, J. Hill, E. Urruty, B. Naughten, K. Gagliardini, O. Durand, G. Gillet-Chaulet, F. Chandler, D. Langebroek, P. Winkelmann, R. |
author_sort |
Reese, R. |
title |
Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_short |
Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_full |
Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_fullStr |
Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_full_unstemmed |
Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_sort |
onset of irreversible retreat of amundsen sea glaciers under current climate on centennial timescales cannot be excluded |
publishDate |
2023 |
url |
http://hdl.handle.net/21.11116/0000-000D-AB7A-A http://hdl.handle.net/21.11116/0000-000D-E92F-9 http://hdl.handle.net/21.11116/0000-000D-E930-6 |
geographic |
Amundsen Sea Antarctic West Antarctic Ice Sheet |
geographic_facet |
Amundsen Sea Antarctic West Antarctic Ice Sheet |
genre |
Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Ice Shelves The Cryosphere |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctica Ice Sheet Ice Shelves The Cryosphere |
op_source |
The Cryosphere |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-17-3761-2023 info:eu-repo/semantics/altIdentifier/doi/10.5194/tc-2022-105 http://hdl.handle.net/21.11116/0000-000D-AB7A-A http://hdl.handle.net/21.11116/0000-000D-E92F-9 http://hdl.handle.net/21.11116/0000-000D-E930-6 |
op_rights |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.5194/tc-17-3761-202310.5194/tc-2022-105 |
_version_ |
1785558933812805632 |