This photo, taken during the NASA ICESCAPE mission in summer 2011, shows melt ponds on the surface of...

A lead or large crack in the ice opens up in melting summer sea ice. A seasonally ice-free Arctic is likely some...

Bright white sea ice reflects light and keeps the Arctic cool. Soot darkens the ice surface and can speed melt...

Despite year-to-year variability, Arctic sea ice has steadily dropped during all seasons since the start of the satellite record in 1979. However, the changes are especially pronounced around the...