The Arctic is currently undergoing rapid environmental changes (ACIA, 2005; IPCC, 2007). One of the most striking of these changes is the decline in the floating sea ice cover. Sea ice is frozen sea water that forms in winter as temperatures drop and darkness sets over the northern high latitudes. At its winter maximum, roughly 14 to 16 million km2 of the Northern Hemisphere ocean surface is covered by sea ice, extending as far south as Newfoundland, Canada (at 50o latitude) along the eastern coast of Canada and as far south as Bohai Bay, China (at 38o latitude) on the Eurasian side. During summer as temperatures warm, the ice cover shrinks to about half its winter size by September, covering on average 6 million km2 (Figure 1).