The largest reductions in snowpack due to climate change have occurred in central and eastern Europe, along with the southwestern and northeastern United States. New research has revealed that seasonal snowpack across the northern hemisphere is have shrunk significantly over the past 40 years due to the effects of climate change. According to the findings, the most affected regions—including Central and Eastern Europe and the southwestern and northeastern United States—lost 10 to 20 % of snow mass. As hundreds of millions of people around the world depend on snowmelt as the main source of water , this loss poses a worrisome challenge to the future security of this vital resource, the study authors warn. "We were most interested in how warming affects the amount of water stored in snow," said Alexander Gottlieb, co-author of the research and a doctoral student at Dartmouth College. "The loss of this reservoir is the most immediate and strongest risk , which climate change represents for society in terms of declining snowfall and accumulation.” (Rory Morrow)