Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies

Abstract The accelerated melting of ice on the Antarctic Peninsula and islands in the sub-Antarctic suggests that the cryosphere is edging towards an irreversible tipping point. How unusual is this trend of ice loss within the frame of natural variability, and to what extent can it be explained by u...

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Autores principales:	Jostein Bakke, Øyvind Paasche, Joerg M Schaefer, Axel Timmermann
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/c250d5b05b8c491f89da113fac1a1c48
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spelling	oai:doaj.org-article:c250d5b05b8c491f89da113fac1a1c482021-12-02T14:27:46ZLong-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies10.1038/s41598-021-87317-52045-2322https://doaj.org/article/c250d5b05b8c491f89da113fac1a1c482021-04-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-87317-5https://doaj.org/toc/2045-2322Abstract The accelerated melting of ice on the Antarctic Peninsula and islands in the sub-Antarctic suggests that the cryosphere is edging towards an irreversible tipping point. How unusual is this trend of ice loss within the frame of natural variability, and to what extent can it be explained by underlying climate dynamics? Here, we present new high-resolution reconstructions of long-term changes in the extents of three glaciers on the island of South Georgia (54°S, 36°W), combining detailed analyses of glacial-derived sediments deposited in distal glacier-fed lakes and cosmogenic exposure dating of moraines. We document that the glaciers of South Georgia have gradually retracted since the Antarctic cold reversal (ACR, 14.5–12.8 ka), culminating in the disappearance of at least one of the reconstructed glaciers. The glacier retreat pattern observed in South Georgia suggests a persistent link to summer insolation at 55°S, which intensified during the period from the ACR to approximately 2 ka. It also reveals multi-decadal to centennial climate shifts superimposed on this long-term trend that have resulted in at least nine glacier readvances during the last 10.5 ka. Accompanying meridional changes in the Southern Hemisphere westerlies and their interconnection with local topography may explain these glacier readvances.Jostein BakkeØyvind PaascheJoerg M SchaeferAxel TimmermannNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-10 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Jostein Bakke Øyvind Paasche Joerg M Schaefer Axel Timmermann Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
description	Abstract The accelerated melting of ice on the Antarctic Peninsula and islands in the sub-Antarctic suggests that the cryosphere is edging towards an irreversible tipping point. How unusual is this trend of ice loss within the frame of natural variability, and to what extent can it be explained by underlying climate dynamics? Here, we present new high-resolution reconstructions of long-term changes in the extents of three glaciers on the island of South Georgia (54°S, 36°W), combining detailed analyses of glacial-derived sediments deposited in distal glacier-fed lakes and cosmogenic exposure dating of moraines. We document that the glaciers of South Georgia have gradually retracted since the Antarctic cold reversal (ACR, 14.5–12.8 ka), culminating in the disappearance of at least one of the reconstructed glaciers. The glacier retreat pattern observed in South Georgia suggests a persistent link to summer insolation at 55°S, which intensified during the period from the ACR to approximately 2 ka. It also reveals multi-decadal to centennial climate shifts superimposed on this long-term trend that have resulted in at least nine glacier readvances during the last 10.5 ka. Accompanying meridional changes in the Southern Hemisphere westerlies and their interconnection with local topography may explain these glacier readvances.
format	article
author	Jostein Bakke Øyvind Paasche Joerg M Schaefer Axel Timmermann
author_facet	Jostein Bakke Øyvind Paasche Joerg M Schaefer Axel Timmermann
author_sort	Jostein Bakke
title	Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
title_short	Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
title_full	Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
title_fullStr	Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
title_full_unstemmed	Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies
title_sort	long-term demise of sub-antarctic glaciers modulated by the southern hemisphere westerlies
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/c250d5b05b8c491f89da113fac1a1c48
work_keys_str_mv	AT josteinbakke longtermdemiseofsubantarcticglaciersmodulatedbythesouthernhemispherewesterlies AT øyvindpaasche longtermdemiseofsubantarcticglaciersmodulatedbythesouthernhemispherewesterlies AT joergmschaefer longtermdemiseofsubantarcticglaciersmodulatedbythesouthernhemispherewesterlies AT axeltimmermann longtermdemiseofsubantarcticglaciersmodulatedbythesouthernhemispherewesterlies
_version_	1718391278139342848

Long-term demise of sub-Antarctic glaciers modulated by the Southern Hemisphere Westerlies

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