Although 2005 overall saw a new record, the extent of June melting in 2005 was unexceptional. The same held true for 2006, when this picture was taken.
Thinner than the 2.3-kilometer-thick center, the outer edges of the Greenland ice sheet develop melt zones like the one shown here during the warm summer months.
Changing weather conditions left their mark on sea ice along the Antarctic Peninsula in late 2008 and early 2009. In mid-December 2008, melt water resting on the sea ice colored it sky blue. At the beginning of 2009, however, the sea ice appeared snowy white, and cracks had begun along the ice margin.
Pools of water grow on top of the ice sheet in summer, then sometimes disappear quickly. That water flushes out through glacial plumbing, carrying sediment and massive volumes of fresh water to the sea.