Retreating sea ice linked to changes in ocean circulation, could affect European climate

Retreating sea ice in the Iceland and Greenland Seas may be changing the circulation of warm and cold water in the Atlantic Ocean, and could ultimately impact the climate in Europe, says a new study by an atmospheric physicist from the University of Toronto Mississauga (UTM) and his colleagues in Great Britain, Norway and the United States. "A warm western Europe requires a cold North Atlantic Ocean, and the warming that the North Atlantic is now experiencing has the potential to result in a cooling over western Europe," says professor G.W.K. Moore of UTM's Department of Chemical & Physical Sciences. As global warming affects the earth and ocean, the retreat of the sea ice means there won't be as much cold, dense water, generated through a process known as oceanic convection, created to flow south and feed the Gulf Stream. If convection decreases, says Moore, the Gulf Stream may weaken, thereby reducing the warming of the atmosphere, in comparison to today. Their research, published in Nature Climate Change on June 29, is the first attempt to examine and document these changes in the air-sea heat exchange in the region—brought about by global warming—and to consider its possible impact on oceanic circulation, including the climatologically important Atlantic Meridional Overturning Circulation. Previous studies have focused instead on the changing salinity of the northern seas and its effects on ocean circulation. Moore and his fellow researchers based their findings on wintertime data from 1958 to 2014 that was provided by the European Centre for Medium-Range Weather Forecasts and model simulations. http://phys.org/news/2015-06-retreating-sea-ice-linked-ocean.html