Arctic ice melting sooner and for longer
The annual Arctic ice melt begins in April, when air and sea
temperatures rise, and continues during the summer until September, when
the sea ice shrinks to a minimum before refreezing over the winter.
Scientists from NASA’s Goddard Space Flight Center used satellite data gathered between 1979 and 2007 to plot melt-season trends in ten Arctic regions. They discovered that the season had lengthened by an average of 20 days during that period, or 6.4 days per decade. Sea ice has started to melt an average of 2.8 days earlier in spring, and begun to refreeze 3.7 days later in autumn.
The study, published in the Journal of Geophysical Research, found that the worst-affected areas are Hudson Bay, the East Greenland Sea, the Laptev and East Siberian seas, and the Chukchi and Beaufort seas, where the melt season had lengthened by more than ten days per decade.
NASA’s Thorsten Markus said that when open water appears earlier in the season, it absorbs more heat from the sun during the summer, increasing the water’s temperature further and exacerbating melting.
‘This feedback process has always been present, yet with more extensive open water, [it] becomes even stronger and further boosts ice loss,’ he said. ‘Melt is starting earlier, but the trend towards a later freeze-up is even stronger because of this.’
April 2010
Scientists from NASA’s Goddard Space Flight Center used satellite data gathered between 1979 and 2007 to plot melt-season trends in ten Arctic regions. They discovered that the season had lengthened by an average of 20 days during that period, or 6.4 days per decade. Sea ice has started to melt an average of 2.8 days earlier in spring, and begun to refreeze 3.7 days later in autumn.
The study, published in the Journal of Geophysical Research, found that the worst-affected areas are Hudson Bay, the East Greenland Sea, the Laptev and East Siberian seas, and the Chukchi and Beaufort seas, where the melt season had lengthened by more than ten days per decade.
NASA’s Thorsten Markus said that when open water appears earlier in the season, it absorbs more heat from the sun during the summer, increasing the water’s temperature further and exacerbating melting.
‘This feedback process has always been present, yet with more extensive open water, [it] becomes even stronger and further boosts ice loss,’ he said. ‘Melt is starting earlier, but the trend towards a later freeze-up is even stronger because of this.’
April 2010
|
FIND OUT WHAT WE'RE TALKING ABOUT ON TWITTER:
|
