Collapse of the North American ice saddle 14,500 years ago caused widespread cooling and reduced ocean overturning circulation

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• 作者：Ruza F. Ivanovic ; Lauren J. Gregoire ; Andrew D. Wickert ; Paul J. Valdes ; Andrea Burke
• 刊名：Geophysical Research Letters
• 出版年：2017
• 出版时间：16 January 2017
• 年：2017
• 卷：44
• 期：1
• 页码：383-392
• 全文大小：6.1MB
• ISSN：1944-8007

文摘

Collapse of ice sheets can cause significant sea level rise and widespread climate change. We examine the climatic response to meltwater generated by the collapse of the Cordilleran-Laurentide ice saddle (North America) ~14.5 thousand years ago (ka) using a high-resolution drainage model coupled to an ocean-atmosphere-vegetation general circulation model. Equivalent to 7.26 m global mean sea level rise in 340 years, the meltwater caused a 6 sverdrup weakening of Atlantic Meridional Overturning Circulation (AMOC) and widespread Northern Hemisphere cooling of 1–5°C. The greatest cooling is in the Atlantic sector high latitudes during Boreal winter (by 5–10°C), but there is also strong summer warming of 1–3°C over eastern North America. Following recent suggestions that the saddle collapse was triggered by the Bølling warming event at ~14.7–14.5 ka, we conclude that this robust submillennial mechanism may have initiated the end of the warming and/or the Older Dryas cooling through a forced AMOC weakening.