Matero, ISO, Gregoire, LJ orcid.org/0000-0003-0258-7282, Ivanovic, RF orcid.org/0000-0002-7805-6018 et al. (2 more authors) (2017) The 8.2 ka cooling event caused by Laurentide ice saddle collapse. Earth and Planetary Science Letters, 473. pp. 205-214. ISSN 0012-821X
Abstract
The 8.2 ka event was a period of abrupt cooling of 1–3 °C across large parts of the Northern Hemisphere, which lasted for about 160 yr. The original hypothesis for the cause of this event has been the outburst of the proglacial Lakes Agassiz and Ojibway. These drained into the Labrador Sea in ∼0.5–5 yr and slowed the Atlantic Meridional Overturning Circulation, thus cooling the North Atlantic region. However, climate models have not been able to reproduce the duration and magnitude of the cooling with this forcing without including additional centennial-length freshwater forcings, such as rerouting of continental runoff and ice sheet melt in combination with the lake release. Here, we show that instead of being caused by the lake outburst, the event could have been caused by accelerated melt from the collapsing ice saddle that linked domes over Hudson Bay in North America. We forced a General Circulation Model with time varying meltwater pulses (100–300 yr) that match observed sea level change, designed to represent the Hudson Bay ice saddle collapse. A 100 yr long pulse with a peak of 0.6 Sv produces a cooling in central Greenland that matches the 160 yr duration and 3 °C amplitude of the event recorded in ice cores. The simulation also reproduces the cooling pattern, amplitude and duration recorded in European Lake and North Atlantic sediment records. Such abrupt acceleration in ice melt would have been caused by surface melt feedbacks and marine ice sheet instability. These new realistic forcing scenarios provide a means to reconcile longstanding mismatches between proxy data and models, allowing for a better understanding of both the sensitivity of the climate models and processes and feedbacks in motion during the disintegration of continental ice sheets.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2017, The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ |
Keywords: | 8.2 ka event; Laurentide ice sheet; ice saddle collapse; abrupt climate change; Atlantic Meridional Overturning Circulation; Paleoclimate |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC UNSPECIFIED NERC NE/K008536/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Jun 2017 10:12 |
Last Modified: | 08 Feb 2021 14:56 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.epsl.2017.06.011 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:117290 |