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

Chris Turney; Zoe Thomas; David Hutchinson; Corey Bradshaw; Barry Brook; Matthew England; Christopher Fogwill; Richard Jones; Jonathan Palmer; Konrad Hughen; Alan Cooper

doi:10.1002/2015GL066344

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

Chris Turney, Zoe Thomas, David Hutchinson, Corey Bradshaw, Barry Brook, Matthew England, Christopher Fogwill, Richard Jones, Jonathan Palmer, Konrad Hughen, Alan Cooper

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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 δ ¹⁸ O 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

Keywords

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

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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 δ 18 O 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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AU - Turney, Chris

AU - Thomas, Zoe

AU - Hutchinson, David

AU - Bradshaw, Corey

AU - Brook, Barry

AU - England, Matthew

AU - Fogwill, Christopher

AU - Jones, Richard

AU - Palmer, Jonathan

AU - Hughen, Konrad

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 δ 18 O 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 δ 18 O 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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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

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Keywords

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