Is a Sleeping Climate Giant Stirring in the Arctic?

Flying low and slow above the wild, pristine terrain of Alaska's North Slope in a specially instrumented NASA plane, research scientist Charles Miller of NASA's Jet Propulsion Laboratory, Pasadena, Calif., surveys the endless whiteness of tundra and frozen permafrost below. On the horizon, a long, dark line appears. The plane draws nearer, and the mysterious object reveals itself to be a