Posted by Lex, on November 13, 2007
NASA scientists now attribute Arctic warming to decadal trends having to do with ocean circulation and salinity, rather than anthropogenic global warming:
Reporting in Geophysical Research Letters, the authors attribute the reversal to a weakened Arctic Oscillation, a major atmospheric circulation pattern in the northern hemisphere. The weakening reduced the salinity of the upper ocean near the North Pole, decreasing its weight and changing its circulation.
“Our study confirms many changes seen in upper Arctic Ocean circulation in the 1990s were mostly decadal in nature, rather than trends caused by global warming,” said Morison.
This may help to explain why Antarctic ice sheets have actually grown thicker over the same time frame.