Sea‐ice feedbacks on the climatic response to precession and obliquity forcing

Abstract

The possible role of sea‐ice feedbacks in the climatic response to orbital forcing at high northern latitudes is studied with a coupled climate model (ECBilt‐CLIO). It is found that boreal summer insolation is critical for the sea‐ice response. When summer insolation is high (low) the sea‐ice fraction decreases (increases) at the margins of the permanent sea‐ice cover during the whole year. More importantly, rapid shifts in GIN (Greenland‐Iceland‐Norway) Sea ice cover are found to be less (more) frequent for relatively high (low) summer insolation. These events, which are characterized by a sudden expansion in sea‐ice cover, result in reduced GIN Sea convection, a reduction of the Atlantic thermohaline circulation by 5–10 Sverdrups and decreased air temperatures at high latitudes.