Talk by Prof. Eystein Jansen

(Dep. of Earth Science/Bjerknes Centre for Climate Research)

Title: The Arctic has entered a new phase of abrupt climate change - an ice2ice perspective

Abstract: Abrupt climate change is a striking feature of many climate records, particularly those documenting temperature changes during the last glacial period. Known as Dansgaard-Oeschger (D-O) events, in Greenland ice core records, these had global repercussions. The abruptness and high amplitude of the D-O warming events are tightly coupled to a rapid retreat of sea ice in the North Atlantic and Nordic Seas. Sea ice loss is also an integral part of the ongoing Arctic warming. We compare current rates of Arctic temperature change with past abrupt temperature changes from the Greenland ice cores and find that modern rates of change are therefore also abrupt. Model simulations of past abrupt changes are commensurable with the reconstructed changes during the last glacial period. Climate models underestimate, however, the current abrupt warming in the Arctic. Only models with high climate sensitivity display abrupt changes within the 21st century, under emissions in accord with the Paris Agreement targets.