The stability of present-day Antarctic grounding lines - Part 2: 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 raise the question of an imminent collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under the present-day climate. To this aim, we first calibr...
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Online Access: | https://hdl.handle.net/11250/3105073 https://doi.org/10.5194/tc-17-3761-2023 |
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ftnorce:oai:norceresearch.brage.unit.no:11250/3105073 2023-12-24T10:08:06+01:00 The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded Reese, Ronja Garbe, Julius Hill, Emily Urruty, Benoit Naughten, Kaitlin Gagliardini, Olivier Durand, Gael Gillet-Chaulet, Fabien Gudmundsson, G. Hilmar Chandler, David Matthew Langebroek, Petra Winkelmann, Ricarda 2023 application/pdf https://hdl.handle.net/11250/3105073 https://doi.org/10.5194/tc-17-3761-2023 eng eng EC/H2020/820575 The Cryosphere. 2023, 17 (9), 3761-3783. urn:issn:1994-0416 https://hdl.handle.net/11250/3105073 https://doi.org/10.5194/tc-17-3761-2023 cristin:2177612 Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no © Author(s) 2023 The Cryosphere 17 9 3761-3783 Peer reviewed Journal article 2023 ftnorce https://doi.org/10.5194/tc-17-3761-2023 2023-11-29T23:50:21Z Observations of ocean-driven grounding-line retreat in the Amundsen Sea Embayment in Antarctica raise the question of an imminent collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under the present-day climate. To this aim, we first calibrate a sub-shelf melt parameterization, which is derived from an ocean box model, with observed and modelled melt sensitivities to ocean temperature changes, making it suitable for present-day simulations and future sea level projections. Using the new calibration, we run an ensemble of historical simulations from 1850 to 2015 with a state-of-the-art ice sheet model to create model instances of possible present-day ice sheet configurations. Then, we extend the simulations for another 10 000 years to investigate their evolution under constant present-day climate forcing and bathymetry. We test for reversibility of grounding-line movement in the case that large-scale retreat occurs. In the Amundsen Sea Embayment we find irreversible retreat of the Thwaites Glacier for all our parameter combinations and irreversible retreat of the Pine Island Glacier for some admissible parameter combinations. Importantly, an irreversible collapse in the Amundsen Sea Embayment sector is initiated at the earliest between 300 and 500 years in our simulations and is not inevitable yet – as also shown in our companion paper (Part 1, Hill et al., 2023). In other words, the region has not tipped yet. With the assumption of constant present-day climate, the collapse evolves on millennial timescales, with a maximum rate of 0.9 mm a−1 sea-level-equivalent ice volume loss. The contribution to sea level by 2300 is limited to 8 cm with a maximum rate of 0.4 mm a−1 sea-level-equivalent ice volume loss. Furthermore, when allowing ice shelves to regrow to their present geometry, we find that large-scale grounding-line retreat into marine basins upstream of the Filchner–Ronne Ice Shelf and the western Siple Coast is reversible. Other grounding lines ... Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Pine Island Pine Island Glacier Ronne Ice Shelf The Cryosphere Thwaites Glacier NORCE vitenarkiv (Norwegian Research Centre) Antarctic Amundsen Sea West Antarctic Ice Sheet Ronne Ice Shelf ENVELOPE(-61.000,-61.000,-78.500,-78.500) Pine Island Glacier ENVELOPE(-101.000,-101.000,-75.000,-75.000) Siple ENVELOPE(-83.917,-83.917,-75.917,-75.917) Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) Siple Coast ENVELOPE(-155.000,-155.000,-82.000,-82.000) The Cryosphere 17 9 3761 3783 |
institution |
Open Polar |
collection |
NORCE vitenarkiv (Norwegian Research Centre) |
op_collection_id |
ftnorce |
language |
English |
description |
Observations of ocean-driven grounding-line retreat in the Amundsen Sea Embayment in Antarctica raise the question of an imminent collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under the present-day climate. To this aim, we first calibrate a sub-shelf melt parameterization, which is derived from an ocean box model, with observed and modelled melt sensitivities to ocean temperature changes, making it suitable for present-day simulations and future sea level projections. Using the new calibration, we run an ensemble of historical simulations from 1850 to 2015 with a state-of-the-art ice sheet model to create model instances of possible present-day ice sheet configurations. Then, we extend the simulations for another 10 000 years to investigate their evolution under constant present-day climate forcing and bathymetry. We test for reversibility of grounding-line movement in the case that large-scale retreat occurs. In the Amundsen Sea Embayment we find irreversible retreat of the Thwaites Glacier for all our parameter combinations and irreversible retreat of the Pine Island Glacier for some admissible parameter combinations. Importantly, an irreversible collapse in the Amundsen Sea Embayment sector is initiated at the earliest between 300 and 500 years in our simulations and is not inevitable yet – as also shown in our companion paper (Part 1, Hill et al., 2023). In other words, the region has not tipped yet. With the assumption of constant present-day climate, the collapse evolves on millennial timescales, with a maximum rate of 0.9 mm a−1 sea-level-equivalent ice volume loss. The contribution to sea level by 2300 is limited to 8 cm with a maximum rate of 0.4 mm a−1 sea-level-equivalent ice volume loss. Furthermore, when allowing ice shelves to regrow to their present geometry, we find that large-scale grounding-line retreat into marine basins upstream of the Filchner–Ronne Ice Shelf and the western Siple Coast is reversible. Other grounding lines ... |
format |
Article in Journal/Newspaper |
author |
Reese, Ronja Garbe, Julius Hill, Emily Urruty, Benoit Naughten, Kaitlin Gagliardini, Olivier Durand, Gael Gillet-Chaulet, Fabien Gudmundsson, G. Hilmar Chandler, David Matthew Langebroek, Petra Winkelmann, Ricarda |
spellingShingle |
Reese, Ronja Garbe, Julius Hill, Emily Urruty, Benoit Naughten, Kaitlin Gagliardini, Olivier Durand, Gael Gillet-Chaulet, Fabien Gudmundsson, G. Hilmar Chandler, David Matthew Langebroek, Petra Winkelmann, Ricarda The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
author_facet |
Reese, Ronja Garbe, Julius Hill, Emily Urruty, Benoit Naughten, Kaitlin Gagliardini, Olivier Durand, Gael Gillet-Chaulet, Fabien Gudmundsson, G. Hilmar Chandler, David Matthew Langebroek, Petra Winkelmann, Ricarda |
author_sort |
Reese, Ronja |
title |
The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_short |
The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_full |
The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_fullStr |
The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_full_unstemmed |
The stability of present-day Antarctic grounding lines - Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded |
title_sort |
stability of present-day antarctic grounding lines - part 2: onset of irreversible retreat of amundsen sea glaciers under current climate on centennial timescales cannot be excluded |
publishDate |
2023 |
url |
https://hdl.handle.net/11250/3105073 https://doi.org/10.5194/tc-17-3761-2023 |
long_lat |
ENVELOPE(-61.000,-61.000,-78.500,-78.500) ENVELOPE(-101.000,-101.000,-75.000,-75.000) ENVELOPE(-83.917,-83.917,-75.917,-75.917) ENVELOPE(-106.750,-106.750,-75.500,-75.500) ENVELOPE(-155.000,-155.000,-82.000,-82.000) |
geographic |
Antarctic Amundsen Sea West Antarctic Ice Sheet Ronne Ice Shelf Pine Island Glacier Siple Thwaites Glacier Siple Coast |
geographic_facet |
Antarctic Amundsen Sea West Antarctic Ice Sheet Ronne Ice Shelf Pine Island Glacier Siple Thwaites Glacier Siple Coast |
genre |
Amundsen Sea Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Pine Island Pine Island Glacier Ronne Ice Shelf The Cryosphere Thwaites Glacier |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctica Filchner Ronne Ice Shelf Filchner-Ronne Ice Shelf Ice Sheet Ice Shelf Ice Shelves Pine Island Pine Island Glacier Ronne Ice Shelf The Cryosphere Thwaites Glacier |
op_source |
The Cryosphere 17 9 3761-3783 |
op_relation |
EC/H2020/820575 The Cryosphere. 2023, 17 (9), 3761-3783. urn:issn:1994-0416 https://hdl.handle.net/11250/3105073 https://doi.org/10.5194/tc-17-3761-2023 cristin:2177612 |
op_rights |
Navngivelse 4.0 Internasjonal http://creativecommons.org/licenses/by/4.0/deed.no © Author(s) 2023 |
op_doi |
https://doi.org/10.5194/tc-17-3761-2023 |
container_title |
The Cryosphere |
container_volume |
17 |
container_issue |
9 |
container_start_page |
3761 |
op_container_end_page |
3783 |
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1786174402760540160 |