Obliquity-driven expansion of North Atlantic sea ice during the last glacial

Chris S.M. Turney; Zoë A. Thomas; David K. Hutchinson; Corey J.A. Bradshaw; Barry W. Brook; Matthew H. England; Christopher J. Fogwill; Richard T. Jones; Jonathan Palmer; Konrad A. Hughen; Alan Cooper

doi:10.1002/2015GL066344

Obliquity-driven expansion of North Atlantic sea ice during the last glacial

Chris S.M. Turney^*, Zoë A. Thomas, David K. Hutchinson, Corey J.A. Bradshaw, Barry W. Brook, Matthew H. England, Christopher J. Fogwill, Richard T. Jones, Jonathan Palmer, Konrad A. Hughen, Alan Cooper

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Pages (from-to)	10382-10390
Number of pages	9
Journal	Geophysical Research Letters
Volume	42
Issue number	23
DOIs	https://doi.org/10.1002/2015GL066344
Publication status	Published - 16 Dec 2015
Externally published	Yes

ASJC Scopus subject areas

Geophysics
General Earth and Planetary Sciences

Keywords

abrupt climate change
geochronology
Greenland ice cores
late Pleistocene
meridional overturning circulation
tipping point

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10.1002/2015GL066344

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title = "Obliquity-driven expansion of North Atlantic sea ice during the last glacial",

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.",

keywords = "abrupt climate change, geochronology, Greenland ice cores, late Pleistocene, meridional overturning circulation, tipping point",

author = "Turney, {Chris S.M.} and Thomas, {Zo{\"e} A.} and Hutchinson, {David K.} and Bradshaw, {Corey J.A.} and Brook, {Barry W.} and England, {Matthew H.} and Fogwill, {Christopher J.} and Jones, {Richard T.} and Jonathan Palmer and Hughen, {Konrad A.} and Alan Cooper",

year = "2015",

month = dec,

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doi = "10.1002/2015GL066344",

language = "English",

volume = "42",

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journal = "Geophysical Research Letters",

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T1 - Obliquity-driven expansion of North Atlantic sea ice during the last glacial

AU - Turney, Chris S.M.

AU - Thomas, Zoë A.

AU - Hutchinson, David K.

AU - Bradshaw, Corey J.A.

AU - Brook, Barry W.

AU - England, Matthew H.

AU - Fogwill, Christopher J.

AU - Jones, Richard T.

AU - Palmer, Jonathan

AU - Hughen, Konrad A.

AU - Cooper, Alan

PY - 2015/12/16

Y1 - 2015/12/16

N2 - 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.

AB - 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.

KW - abrupt climate change

KW - geochronology

KW - Greenland ice cores

KW - late Pleistocene

KW - meridional overturning circulation

KW - tipping point

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DO - 10.1002/2015GL066344

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AN - SCOPUS:84953639500

SN - 0094-8276

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SP - 10382

EP - 10390

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 23

ER -

Obliquity-driven expansion of North Atlantic sea ice during the last glacial

Abstract

ASJC Scopus subject areas

Keywords

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