SAN FRANCISCO, CALIFORNIA—Just last spring, 2012 appeared on track to be a relatively unremarkable year in the Arctic. Throughout the year, in fact, surface air temperatures—which largely drive melting—seemed unexceptional. But, as scientists including National Oceanic and Atmospheric Administration (NOAA) Administrator Jane Lubchenco said today at a press conference at the American Geophysical Union's fall meeting, record-setting melting happened anyway: record snow melt, record sea ice minimum, melting even at the top of the Greenland ice sheet (in what was once called the "dry snow zone"), and widespread warming of permafrost.
The researchers announced the release of the 2012 Arctic Report Card, an annual description of the state of the Arctic that is sponsored by NOAA's Arctic Research Program, part of its Climate Program Office. NOAA published the first Arctic Report Card in 2006. Nearly 150 scientists from 15 countries contributed to this year's report, which looked not only at the melting events, but also examined changes to the growing season, weather events, and ecosystem-wide impacts from phytoplankton blooms to the loss of Arctic megafauna.
The widespread melting across the Greenland ice sheet was one of the most dramatic changes, said Jason Box of the Byrd Polar Research Center at Ohio State University in Columbus. "I've studied Greenland for 20 years—devoted my career to it," he said at the press conference. "And 2012 was an astonishing year." Box pointed to nearly ice-sheet-wide melting on Greenland, with extensive surface melting documented for first time at the highest elevations of ice sheet, and the longest melt season since satellite observations began in 1979.