In northern Alaska, ponds are shrinking and disappearing as the frozen ground beneath them thaws. The loss may have serious consequences for migratory birds and the subsistence hunters that depend on them.
Why on Earth are climate scientists so interested in the West Antarctic ice sheet? This remote region of the seventh continent has been the subject of many recent research explorations--the results of which have been described in the news with words like “collapse,” “irreversible,” and “huge.”
From reindeer to regional temperature patterns, from sea ice age to Greenland surface melt, the Arctic Report Card is a yearly assessment of the Arctic's physical and biological systems and how they are changing. This collection of visual highlights from the 2013 report is a story of the Arctic in pictures.
The 2012 Arctic sea ice extent was nearly 50 percent smaller than the long-term (1979-2000) average. For sea ice to have shrunk to half its historic summer extent is as much a transformation of the environment as if half the forests of New England had been replaced by cactus.
The summer of 2012 brought Greenland far more extensive melt than anything observed in the satellite record: in July 2012, surface melt extended over nearly the entire ice sheet. The standardized melt index was nearly double the previous record.
For James Overland, an Arctic oceanographer at NOAA’s Pacific Marine Environmental Laboratory, six exceptionally slushy summers in a row in the Arctic demanded an explanation that went beyond the obvious: that global warming is raising the Arctic’s temperature. After analyzing winds and pressure patterns, Overland and several colleagues documented an unusual shift in the prevailing June winds—from westerlies to southerly—that amplified Arctic warming and sea ice melt.
A series of unusually strong, long-lasting high pressure systems has parked over Greenland this summer. As many a weather forecaster has explained, high pressure generally leads to calm winds and sunny skies, both of which boost temperatures during the all-day sunshine of mid-summer at high latitudes. The conditions contributed to widespread melting of the ice sheet.