Toward an ice-free Barents Sea

Arctic winter sea ice loss is most pronounced in the Barents Sea. Here we combine observations since 1850 with climate model simulations to examine the recent record low winter Barents Sea ice extent. We find that the present observed winter Barents Sea ice extent has been reduced to less than one third of the pre-satellite mean and is lower than the minimum sea ice extent in all multicentury climate model control simulations assessed here. The current observed sea ice loss is furthermore unprecedented in the observational record and appears as an uncommon trend in the long control simulations. In a warming climate, projections from the large ensemble simulation with the Community Earth System Model show a winter ice-free Barents Sea for the first time within the time period 2061-2088. The large spread in projections of ice-free conditions highlights the importance of internal variability in driving recent and future sea ice loss.