NASA: Is a Sleeping Climate Giant Stirring in the Arctic? Permafrost zones occupy nearly a quarter of the exposed land area of the Northern Hemisphere. NASA’s Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) is probing deep into the frozen lands above the Arctic Circle in Alaska to measure emissions of the greenhouse gases carbon dioxide and methane from thawing permafrost – signals that may hold a key to Earth’s climate future. Image credit: Hugo Ahlenius, UNEP/GRID-Arendal