Rapid fragmentation of Thwaites Eastern Ice Shelf
Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implic...
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Language: | English |
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Copernicus Publications
2022
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Online Access: | https://doi.org/10.5194/tc-16-2545-2022 https://doaj.org/article/3bba9227fc474be2acf2e101724fedd7 |
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ftdoajarticles:oai:doaj.org/article:3bba9227fc474be2acf2e101724fedd7 2023-05-15T13:47:23+02:00 Rapid fragmentation of Thwaites Eastern Ice Shelf D. I. Benn A. Luckman J. A. Åström A. J. Crawford S. L. Cornford S. L. Bevan T. Zwinger R. Gladstone K. Alley E. Pettit J. Bassis 2022-06-01T00:00:00Z https://doi.org/10.5194/tc-16-2545-2022 https://doaj.org/article/3bba9227fc474be2acf2e101724fedd7 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/2545/2022/tc-16-2545-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-2545-2022 1994-0416 1994-0424 https://doaj.org/article/3bba9227fc474be2acf2e101724fedd7 The Cryosphere, Vol 16, Pp 2545-2564 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-2545-2022 2022-12-31T03:09:33Z Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implications for ice-sheet stability. Here, we focus on the Thwaites Eastern Ice Shelf (TEIS), the remaining pinned floating extension of Thwaites Glacier. We show that TEIS has undergone a process of fragmentation in the last 5 years, including brittle failure along a major shear zone, formation of tensile cracks on the main body of the shelf, and a release of tabular bergs on both the eastern and western flanks. Simulations with the Helsinki Discrete Element Model (HiDEM) show that this pattern of failure is associated with high backstress from a submarine pinning point at the distal edge of the shelf. We show that a significant zone of shear, upstream of the main pinning point, developed in response to the rapid acceleration of the shelf between 2002 and 2006, seeding damage on the shelf. Subsequently, basal melting and positive feedback between damage and strain rates weakened TEIS, allowing damage to accumulate. Thus, although backstress on TEIS has likely diminished over time as the pinning point shrunk, accumulation of damage has ensured that the ice in the shear zone remained the weakest link in the system. Experiments with the BISICLES ice-sheet model indicate that additional damage to or unpinning of TEIS is unlikely to trigger significantly increased ice loss from WAIS, but the calving response to the loss of TEIS remains highly uncertain. It is widely recognised that ice-shelf fragmentation and collapse can be triggered by hydrofracturing and/or unpinning from ice-shelf margins or grounding points. Our results indicate a third mechanism, backstress triggered failure , that can occur if and when an ice shelf is no longer able to withstand stress imposed by pinning points. In most circumstances, pinning points are ... Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves The Cryosphere Thwaites Glacier Directory of Open Access Journals: DOAJ Articles Antarctic West Antarctic Ice Sheet Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) The Cryosphere 16 6 2545 2564 |
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 D. I. Benn A. Luckman J. A. Åström A. J. Crawford S. L. Cornford S. L. Bevan T. Zwinger R. Gladstone K. Alley E. Pettit J. Bassis Rapid fragmentation of Thwaites Eastern Ice Shelf |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Ice shelves play a key role in the dynamics of marine ice sheets by buttressing grounded ice and limiting rates of ice flux to the oceans. In response to recent climatic and oceanic change, ice shelves fringing the West Antarctic Ice Sheet (WAIS) have begun to fragment and retreat, with major implications for ice-sheet stability. Here, we focus on the Thwaites Eastern Ice Shelf (TEIS), the remaining pinned floating extension of Thwaites Glacier. We show that TEIS has undergone a process of fragmentation in the last 5 years, including brittle failure along a major shear zone, formation of tensile cracks on the main body of the shelf, and a release of tabular bergs on both the eastern and western flanks. Simulations with the Helsinki Discrete Element Model (HiDEM) show that this pattern of failure is associated with high backstress from a submarine pinning point at the distal edge of the shelf. We show that a significant zone of shear, upstream of the main pinning point, developed in response to the rapid acceleration of the shelf between 2002 and 2006, seeding damage on the shelf. Subsequently, basal melting and positive feedback between damage and strain rates weakened TEIS, allowing damage to accumulate. Thus, although backstress on TEIS has likely diminished over time as the pinning point shrunk, accumulation of damage has ensured that the ice in the shear zone remained the weakest link in the system. Experiments with the BISICLES ice-sheet model indicate that additional damage to or unpinning of TEIS is unlikely to trigger significantly increased ice loss from WAIS, but the calving response to the loss of TEIS remains highly uncertain. It is widely recognised that ice-shelf fragmentation and collapse can be triggered by hydrofracturing and/or unpinning from ice-shelf margins or grounding points. Our results indicate a third mechanism, backstress triggered failure , that can occur if and when an ice shelf is no longer able to withstand stress imposed by pinning points. In most circumstances, pinning points are ... |
format |
Article in Journal/Newspaper |
author |
D. I. Benn A. Luckman J. A. Åström A. J. Crawford S. L. Cornford S. L. Bevan T. Zwinger R. Gladstone K. Alley E. Pettit J. Bassis |
author_facet |
D. I. Benn A. Luckman J. A. Åström A. J. Crawford S. L. Cornford S. L. Bevan T. Zwinger R. Gladstone K. Alley E. Pettit J. Bassis |
author_sort |
D. I. Benn |
title |
Rapid fragmentation of Thwaites Eastern Ice Shelf |
title_short |
Rapid fragmentation of Thwaites Eastern Ice Shelf |
title_full |
Rapid fragmentation of Thwaites Eastern Ice Shelf |
title_fullStr |
Rapid fragmentation of Thwaites Eastern Ice Shelf |
title_full_unstemmed |
Rapid fragmentation of Thwaites Eastern Ice Shelf |
title_sort |
rapid fragmentation of thwaites eastern ice shelf |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-2545-2022 https://doaj.org/article/3bba9227fc474be2acf2e101724fedd7 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic West Antarctic Ice Sheet Thwaites Glacier |
geographic_facet |
Antarctic West Antarctic Ice Sheet Thwaites Glacier |
genre |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves The Cryosphere Thwaites Glacier |
genre_facet |
Antarc* Antarctic Ice Sheet Ice Shelf Ice Shelves The Cryosphere Thwaites Glacier |
op_source |
The Cryosphere, Vol 16, Pp 2545-2564 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/2545/2022/tc-16-2545-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-2545-2022 1994-0416 1994-0424 https://doaj.org/article/3bba9227fc474be2acf2e101724fedd7 |
op_doi |
https://doi.org/10.5194/tc-16-2545-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
6 |
container_start_page |
2545 |
op_container_end_page |
2564 |
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1766247063764336640 |