Obliquity-driven expansion of North Atlantic sea ice during the last glacial
Obliquity-driven expansion of North Atlantic sea ice during the last glacial
North Atlantic late Pleistocene climate (60,000 to 11,650 years ago) was characterized by abrupt and extreme millennial duration oscillations known as Dansgaard-Oeschger (D-O) events. However, during the Last Glacial Maximum (LGM) 23,000 to 19,000 cal years ago (23 to 19 ka), no D-O events are observed in the Greenland ice cores. Our new analysis of the Greenland δ18O record reveals a switch in the stability of the climate system around 30 ka, suggesting that a critical threshold was passed. Climate system modeling suggests that low axial obliquity at this time caused vastly expanded sea ice in the Labrador Sea, shifting Northern Hemisphere westerly winds south and reducing the strength of meridional overturning circulation. The results suggest that these feedbacks tipped the climate system into full glacial conditions, leading to maximum continental ice growth during the LGM.
abrupt climate change, geochronology, Greenland ice cores, late Pleistocene, meridional overturning circulation, tipping point
10382-10390
Turney, Chris S.M.
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Thomas, Zoë A.
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Hutchinson, David K.
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Bradshaw, Corey J.A.
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Brook, Barry W.
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England, Matthew H.
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Fogwill, Christopher J.
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Jones, Richard T.
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Palmer, Jonathan
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Hughen, Konrad A.
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Cooper, Alan
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16 December 2015
Turney, Chris S.M.
5149b57c-77c2-4375-97a2-a4f00aa74d97
Thomas, Zoë A.
4b512d3a-3478-4270-9fdd-61256aa640d3
Hutchinson, David K.
9db108b8-88f0-4c3a-a61b-0af71ab97501
Bradshaw, Corey J.A.
909e397d-4fb2-4647-b6a3-4680002bf236
Brook, Barry W.
7a3c9230-5ad5-4938-b38e-5ba2b47c4c5d
England, Matthew H.
420875c0-8efb-4d92-9dca-249cfe5927b9
Fogwill, Christopher J.
3bad6ae9-5a6d-467e-b523-9d5ed0147455
Jones, Richard T.
f8b5db51-10c7-4b4e-81e3-e5c3833eb2ce
Palmer, Jonathan
6b327a39-f234-4cdc-ae73-0c48340f05b3
Hughen, Konrad A.
f7b3b803-edd7-46b4-bc7a-0bf2bf380f62
Cooper, Alan
19dc1ef7-30e4-4549-9c58-3eee5aa06ea6
Turney, Chris S.M., Thomas, Zoë A. and Hutchinson, David K.
,
et al.
(2015)
Obliquity-driven expansion of North Atlantic sea ice during the last glacial.
Geophysical Research Letters, 42 (23), .
(doi:10.1002/2015GL066344).
Abstract
North Atlantic late Pleistocene climate (60,000 to 11,650 years ago) was characterized by abrupt and extreme millennial duration oscillations known as Dansgaard-Oeschger (D-O) events. However, during the Last Glacial Maximum (LGM) 23,000 to 19,000 cal years ago (23 to 19 ka), no D-O events are observed in the Greenland ice cores. Our new analysis of the Greenland δ18O record reveals a switch in the stability of the climate system around 30 ka, suggesting that a critical threshold was passed. Climate system modeling suggests that low axial obliquity at this time caused vastly expanded sea ice in the Labrador Sea, shifting Northern Hemisphere westerly winds south and reducing the strength of meridional overturning circulation. The results suggest that these feedbacks tipped the climate system into full glacial conditions, leading to maximum continental ice growth during the LGM.
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Accepted/In Press date: 17 November 2015
Published date: 16 December 2015
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Publisher Copyright:
© 2015. American Geophysical Union. All Rights Reserved.
Keywords:
abrupt climate change, geochronology, Greenland ice cores, late Pleistocene, meridional overturning circulation, tipping point
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Local EPrints ID: 476637
URI: http://eprints.soton.ac.uk/id/eprint/476637
ISSN: 0094-8276
PURE UUID: a2f48845-12e5-461e-8942-0c7f327b44b8
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Date deposited: 10 May 2023 16:48
Last modified: 17 Mar 2024 04:18
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Contributors
Author:
Chris S.M. Turney
Author:
Zoë A. Thomas
Author:
David K. Hutchinson
Author:
Corey J.A. Bradshaw
Author:
Barry W. Brook
Author:
Matthew H. England
Author:
Christopher J. Fogwill
Author:
Richard T. Jones
Author:
Jonathan Palmer
Author:
Konrad A. Hughen
Author:
Alan Cooper
Corporate Author: et al.
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