Arctic melt season lengthening in positive feedback loop
January 28th, 2010New NASA-led research shows that the melt season for Arctic sea ice has lengthened by an average of 20 days over the span of 28 years, or 6.4 days per decade.
The research team discovered that the melt season lengthened the most – more than 10 days per decade – in Hudson Bay, the East Greenland Sea, the Laptev and East Siberian Seas, and the Chukchi and Beaufort Seas.
Earlier melt means more heat can be absorbed by the open water, promoting more melting and later freeze-up dates — more than eight days per decade later in some areas.
Thorsten Markus of NASA’s Goddard Space Flight Center in Greenbelt, Md. explains how the feedback loop works:
This feedback process has always been present, yet with more extensive open water this feedback becomes even stronger and further boosts ice loss. Melt is starting earlier, but the trend towards a later freeze-up is even stronger because of this feedback effect.