Warm summers during the Younger Dryas cold reversal

The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, i...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Schenk, Frederik, Väliranta, Minna, Muschitiello, Francesco, Tarasov, Lev, Heikkilä, Maija, Björck, Svante, Brandefelt, Jenny, Johansson, Arne V., Näslund, Jens-Ove, Wohlfarth, Barbara
Other Authors: Helsinki Institute of Sustainability Science (HELSUS), Ecosystems and Environment Research Programme, Doctoral Programme in Interdisciplinary Environmental Sciences, Environmental Change Research Unit (ECRU)
Format: Article in Journal/Newspaper
Language:English
Published: Nature Publishing Group 2018
Subjects:
BP
Online Access:http://hdl.handle.net/10138/238898
Description
Summary:The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons. Peer reviewed