As the Eastern US ends what seems to have been the most severe winter in memory, it is hard to remember that the global climate is still warming. A severe winter in a region doesn’t mean that the entire hemisphere had an extreme winter. And it really doesn’t imply much about long term trends. A key indicator of long term trends is the length of the Arctic melt season.
A new study by researchers from the National Snow and Ice Data Center (NSIDC) and NASA shows that the length of the melt season for Arctic sea ice is growing by several days each decade. An earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation in some places to melt as much as four feet of the Arctic ice cap’s thickness.
“The Arctic is warming and this is causing the melt season to last longer,” said Julienne Stroeve, a senior scientist at NSIDC, Boulder and lead author of the new study, which has been accepted for publication in Geophysical Research Letters. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the ocean and increase ice melt during the summer, overall weakening the sea ice cover.”