云层也会影响格陵兰冰盖的融化

The Greenland Ice Sheet is the second largest ice sheet in the world and it's melting rapidly, likely driving almost a third of global sea level rise. A new study shows clouds are playing a larger role in that process than scientists previously believed.

"Over the next 80 years, we could be dealing with another foot of sea level rise around the world," says Tristan L'Ecuyer, professor in the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison and co-author of the study. "Parts of Miami and New York City are less than two feet above sea level; another foot of sea level rise and suddenly you have water in the city."

The study, published today (Jan. 12, 2016) in Nature Communications and led by the University of Leuven in Belgium, shows that clouds are raising the temperature of the Greenland Ice Sheet by 2 to 3 degrees compared to cloudless skies and accounting for as much as 30 percent of the ice sheet melt.

Numerous statements in the Nobel Peace Prize-winning 2007 Intergovernmental Panel on Climate Change report address the need to better account for clouds in climate models, L'Ecuyer says. Arctic clouds are no exception, especially since climate models have not kept pace with the rate of melting actually observed on the Greenland Ice Sheet.

"With climate change at the back of our minds, and the disastrous consequences of a global sea level rise, we need to understand these processes to make more reliable projections for the future," says Kristof Van Tricht, the University of Leuven graduate student who led the study. "Clouds are more important for that purpose than we used to think."