J. Geophys. Res. 114, C07005 (2009)
Thin sea ice is becoming increasingly common in the Arctic Ocean, according to the most comprehensive satellite survey of the region yet. The findings add to the slew of evidence that Arctic sea ice is rapidly shrinking in all dimensions.
A research team led by Ron Kwok of NASA's Jet Propulsion Laboratory in Pasadena, California, estimated changes in the thickness and volume of the Arctic's perennial blanket of sea ice over a five-year period. Their analysis of data collected by the space agency's Ice, Cloud and land Elevation Satellite (ICESat) reveals that between 2003 and 2008, Arctic multi-year sea ice thinned by about seven inches a year. Over this period, the total area covered by multi-year ice also shrank to just 42 per cent of its former size. The overall area of sea ice lost is equal in size to Alaska's entire land surface.
The changes are so dramatic that seasonal ice, averaging six feet in thickness, now constitutes a greater proportion of Arctic sea ice than the typically chunkier multi-year ice, which usually approaches nine feet in thickness.