Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2
The Southern Hemisphere westerly winds influence deep ocean circulation and carbon storage. While the westerlies are hypothesized to play a key role in regulating atmospheric CO2 over glacial-interglacial cycles, past changes in their position and strength remain poorly constrained. Here, we use a c...
Published in: | Paleoceanography and Paleoclimatology |
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American Geophysical Union (AGU)
2023
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Online Access: | http://hdl.handle.net/1959.4/unsworks_83906 https://doi.org/10.1029/2023PA004666 |
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ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_83906 2024-06-02T08:14:20+00:00 Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 Gray, WR de Lavergne, C Jnglin Wills, RC Menviel, L Spence, P Holzer, M Kageyama, M Michel, E 2023-07-01 http://hdl.handle.net/1959.4/unsworks_83906 https://doi.org/10.1029/2023PA004666 unknown American Geophysical Union (AGU) http://purl.org/au-research/grants/arc/DP210101650 http://hdl.handle.net/1959.4/unsworks_83906 https://doi.org/10.1029/2023PA004666 metadata only access http://purl.org/coar/access_right/c_14cb CC-BY https://creativecommons.org/licenses/by/4.0/ urn:ISSN:2572-4517 urn:ISSN:2572-4525 Paleoceanography and Paleoclimatology, 38, 7 13 Climate Action 14 Life Below Water journal article http://purl.org/coar/resource_type/c_6501 2023 ftunswworks https://doi.org/10.1029/2023PA004666 2024-05-07T23:48:05Z The Southern Hemisphere westerly winds influence deep ocean circulation and carbon storage. While the westerlies are hypothesized to play a key role in regulating atmospheric CO2 over glacial-interglacial cycles, past changes in their position and strength remain poorly constrained. Here, we use a compilation of planktic foraminiferal δ18O from across the Southern Ocean and emergent relationships within an ensemble of climate models to reconstruct changes in the Southern Hemisphere surface westerlies over the last deglaciation. We infer a 4.8° (2.9–7.1°, 95% confidence interval) equatorward shift and about a 25% weakening of the westerlies during the Last Glacial Maximum (20 ka) relative to the mid-Holocene (6.5 ka). Climate models from the Palaeoclimate Modeling Intercomparison Project substantially underestimate this inferred equatorward wind shift. According to our reconstruction, the poleward shift in the westerlies over deglaciation closely mirrors the rise in atmospheric CO2 (R2 = 0.98). Experiments with a 0.25° resolution ocean-sea-ice-carbon model suggest that shifting the westerlies equatorward reduces the overturning rate of the ocean below 2 km depth, leading to a suppression of CO2 outgassing from the polar Southern Ocean. Our results support a role for the westerly winds in driving the deglacial CO2 rise, and suggest outgassing of natural CO2 from the Southern Ocean is likely to increase as the westerlies shift poleward due to anthropogenic warming. Article in Journal/Newspaper Sea ice Southern Ocean UNSW Sydney (The University of New South Wales): UNSWorks Southern Ocean Paleoceanography and Paleoclimatology 38 7 |
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Open Polar |
collection |
UNSW Sydney (The University of New South Wales): UNSWorks |
op_collection_id |
ftunswworks |
language |
unknown |
topic |
13 Climate Action 14 Life Below Water |
spellingShingle |
13 Climate Action 14 Life Below Water Gray, WR de Lavergne, C Jnglin Wills, RC Menviel, L Spence, P Holzer, M Kageyama, M Michel, E Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
topic_facet |
13 Climate Action 14 Life Below Water |
description |
The Southern Hemisphere westerly winds influence deep ocean circulation and carbon storage. While the westerlies are hypothesized to play a key role in regulating atmospheric CO2 over glacial-interglacial cycles, past changes in their position and strength remain poorly constrained. Here, we use a compilation of planktic foraminiferal δ18O from across the Southern Ocean and emergent relationships within an ensemble of climate models to reconstruct changes in the Southern Hemisphere surface westerlies over the last deglaciation. We infer a 4.8° (2.9–7.1°, 95% confidence interval) equatorward shift and about a 25% weakening of the westerlies during the Last Glacial Maximum (20 ka) relative to the mid-Holocene (6.5 ka). Climate models from the Palaeoclimate Modeling Intercomparison Project substantially underestimate this inferred equatorward wind shift. According to our reconstruction, the poleward shift in the westerlies over deglaciation closely mirrors the rise in atmospheric CO2 (R2 = 0.98). Experiments with a 0.25° resolution ocean-sea-ice-carbon model suggest that shifting the westerlies equatorward reduces the overturning rate of the ocean below 2 km depth, leading to a suppression of CO2 outgassing from the polar Southern Ocean. Our results support a role for the westerly winds in driving the deglacial CO2 rise, and suggest outgassing of natural CO2 from the Southern Ocean is likely to increase as the westerlies shift poleward due to anthropogenic warming. |
format |
Article in Journal/Newspaper |
author |
Gray, WR de Lavergne, C Jnglin Wills, RC Menviel, L Spence, P Holzer, M Kageyama, M Michel, E |
author_facet |
Gray, WR de Lavergne, C Jnglin Wills, RC Menviel, L Spence, P Holzer, M Kageyama, M Michel, E |
author_sort |
Gray, WR |
title |
Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
title_short |
Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
title_full |
Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
title_fullStr |
Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
title_full_unstemmed |
Poleward Shift in the Southern Hemisphere Westerly Winds Synchronous With the Deglacial Rise in CO 2 |
title_sort |
poleward shift in the southern hemisphere westerly winds synchronous with the deglacial rise in co 2 |
publisher |
American Geophysical Union (AGU) |
publishDate |
2023 |
url |
http://hdl.handle.net/1959.4/unsworks_83906 https://doi.org/10.1029/2023PA004666 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Sea ice Southern Ocean |
genre_facet |
Sea ice Southern Ocean |
op_source |
urn:ISSN:2572-4517 urn:ISSN:2572-4525 Paleoceanography and Paleoclimatology, 38, 7 |
op_relation |
http://purl.org/au-research/grants/arc/DP210101650 http://hdl.handle.net/1959.4/unsworks_83906 https://doi.org/10.1029/2023PA004666 |
op_rights |
metadata only access http://purl.org/coar/access_right/c_14cb CC-BY https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1029/2023PA004666 |
container_title |
Paleoceanography and Paleoclimatology |
container_volume |
38 |
container_issue |
7 |
_version_ |
1800738136089690112 |