Age of Arctic Sea Ice in February 2008. The February 2008 ice pack (right) contained much more young ice than the long-term average (left). In the mid- to late 1980s, over 20 percent of Arctic sea ice was at least six years old; in February 2008, just 6 percent of the ice was six years old or older.
Old sea ice, which had survived several summers, used to dominate the sea ice of the winter Arctic. However, today less than half of the sea ice at winter maximum has survived at least one summer. NOAA’s climatewatch has a video of the loss of arctic sea ice.
via Eddy Carmack