Paul Pregont has just mushed his team of huskies across miles of Arctic wasteland. It is 45 degrees below zero, but important clues about the effects of global warming may be locked inside the ice under his feet. Pregont is the point man in a NASA-sponsored foot patrol aimed at measuring water resources in the far north. The stakes involved in this research could be enormous. Roughly 70 percent of the water supply in western states comes from melting snow pack, experts say, while the Himalayas feed rivers that supply water to over a half billion people. ‘In recent years, snow cover has been declining in many areas of the globe,’ says Jim Foster, a physical scientist at the NASA hydrological sciences branch in Maryland. ‘It has become ever more important to accurately measure the amount of snow in large watersheds.’ NASA has been monitoring the Arctic snow cap using satellites since the late ’80s, measuring cloud formations to soil moisture from miles above the Earth’s surface. But the shape and size of the snow crystals can scatter their sensors and distort the readings, and now the U.S. space agency is making a concerted push to collect […]