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Causes of abrupt climate change

What caused abrupt climate swings known as the Dansgaard-Oeschger events of the last ice age?

Camille_Dansgaard-Oeschger_map
The Northern Seas. Purple arrows represent surface currents, dashed orange arrows deep currents, and SPG the subpolar gyre. Shading shows annual mean sea surface temperature and sea ice concentration.
Photo:
Camille Li and Anders Born

In this review, we speculate that the subpolar North Atlantic hit a sweet spot, possible in a glacial world but not today, where positive feedbacks between winds, sea ice and ocean circulation created large, sustained climate oscillations.

Reference

Camille Li, Andreas Born: Coupled atmosphere-ice-ocean dynamics in Dansgaard-Oeschger events,Quaternary Science Reviews, Volume 203, 2019,Pages 1-20,ISSN 0277-3791, doi.org/10.1016/j.quascirev.2018.10.031.

This is also publised at the web-pages of The Bjerknes Centre for climate research.