National Geographic: Part of Alaska’s coast is drifting into the sea at twice the rate it has in the past, reshaping the Arctic shoreline, a new study says. The trend could seriously threaten the area’s caribou and other wildlife, as well as local landmarks that document human settlements. Some stretches of the state’s northern shore along the Beaufort Sea receded by more than 80 feet (25 meters) in summer 2007 alone, when Arctic sea ice was at a record low. In the past, spurts of erosion …