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Collapse of the North American ice saddle 14,500 years ago caused widespread cooling and reduced ocean overturning circulation
Author(s) -
Ivanovic Ruza F.,
Gregoire Lauren J.,
Wickert Andrew D.,
Valdes Paul J.,
Burke Andrea
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071849
Subject(s) - younger dryas , geology , meltwater , climatology , thermohaline circulation , oceanography , arctic ice pack , shutdown of thermohaline circulation , sea ice , ice sheet , glacial period , north atlantic deep water , climate change , paleontology
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.