Sea Ice
Artic sea ice has been shrinking dramatically, and the rate of loss is accelerating. In September 2012, Artic summer sea ice fell to a new record low at half the historical average-a loss in area nearly twice the size of Alaska.
Ice sheets and Glaciers
The melting of the Greenland and Antarctica ice sheets has also accelerated notably. Glaciers continue to melt rapidly, contributing to sea-level rise and also affecting water supplies for as many as a billion people around the world.