In June 2012, snow cover extent over Eurasia and North America hit a new record low. It is the third time in five years that North America has set a new record low, and the fifth year in a row that Eurasia has. The rate of snow cover loss over Northern Hemisphere land areas in June between 1979 and 2012 is -17.6% per decade—a faster decline than September sea ice loss over the same period.
On a yearly basis, Arctic temperatures are strongly influenced by natural climate patterns, including the Arctic and North Atlantic Oscillations. Over the span of a decade, though, Arctic amplification of climate change is evident: no part of the Arctic was cooler than the long-term average.
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its historic summer extent is as much a transformation of the environment as if half the forests of New England had been replaced by cactus.
Windell’s Levee: Protecting a Coastal Community
November 27, 2012
Everything’s Moving: Relative Sea Level Rise Explained
November 27, 2012
Advanced Coastal GPS: Immediate Data, Immediate Decisions
November 27, 2012
The average global temperature for October 2012 was the fifth warmest October since recordkeeping began in 1880.
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.
September 2012 tied with September 2005 as the warmest September worldwide since record keeping began in 1880. See which countries saw warmer-than-average temperatures during last month, and learn how weak El Niño conditions might progress into the Northern Hemisphere winter.
The Heat is On
October 9, 2012