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Ice-shelf collapse from subsurface warming as a trigger for Heinrich events

Marcott, Shaun A., Clark, Peter U, Padman, Laurie, Klinkhammer, Gary P., Springer, Scott R., Liu, Zhengyu, Otto-Bliesner, Bette L., Carlson, Anders E., Ungerer, Andy, Padman, June, He, Feng, Cheng, Jun and Schmittner, Andreas (2011) Ice-shelf collapse from subsurface warming as a trigger for Heinrich events. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 108 (33). pp. 13415-13419. [Journal article]

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DOI: 10.1073/pnas.1104772108

Abstract

Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2 °C over a 1–2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically active ice shelf, the increase in subsurface temperature increases basal melt rate under an ice shelf fronting the HSIS by a factor of approximately 6. By analogy with recent observations in Antarctica, the resulting ice-shelf loss and attendant HSIS acceleration would produce a Heinrich event.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences > School of Geography and Environmental Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Environmental Sciences Research Institute > Quaternary Environmental Change
Environmental Sciences Research Institute
ID Code:27121
Deposited By: Mrs Linda Allen
Deposited On:29 Sep 2013 08:26
Last Modified:09 May 2016 11:17

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