Global warming set to bring colder, snowier winters

Kate Ravilious in Environmental Research Web: The world is getting warmer, which should mean warmer winters - right? Wrong - a new study shows that global warming produces colder winters and heavier dumps of snow for large swathes of the northern hemisphere.

In Canada it was dubbed 'Snowmageddon', while the Brits called it 'The Big Freeze'. Across Europe and the eastern United States temperatures plummeted for weeks on end during the winter of 2009/2010 and heavy snowfall caused major disruption. And then it happened all over again during the winter of 2010/2011, causing many to question whether global warming was happening at all. Now research suggests that colder winters have become more frequent over the past two decades, and were likely a product of global warming.

Judah Cohen, from Atmospheric and Environmental Research (AER) in Massachusetts, US, and his colleagues studied northern hemisphere temperature, humidity, snow cover, and sea ice cover data from the last twenty years. They show that as northern hemisphere summer temperatures have risen, September sea ice cover on the Arctic Ocean has shrunk. At the same time atmospheric moisture levels in the Arctic have risen, October snowfall across Europe has increased, and winters have become colder (Environmental Research Letters).

...The new data suggests that the probability of a negative Arctic Oscillation establishing has been increasing since the 1980s, and Cohen sees no reason why increasing autumn snow cover will cease to favour a negative winter Arctic Oscillation in the coming decades. However, if summer and autumn temperatures continue to rise then the extra atmospheric moisture may fall as autumn rain, rather than snow.....

Nicknamed “snowpocalypse” and “snowmageddon,” an exceptionally severe winter storm dropped several feet of snow around the Washington, D.C., area in early February 2010. Crashed and abandoned cars littered roads as airlines canceled hundreds of flights. Even the DC Metro train system stopped functioning in places. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this true-color image on February 7, 2010, showing part of the region affected by heavy snowfall. Snow blankets the area hundreds of kilometers inland from the Atlantic coastline. Along the latitude of New York City, however, snow cover thins considerably.