Watch as sea ice in the Arctic ocean declines from its near-maximum state in early spring 2011 through the summer and up until Sept. 9, 2011, in this visualization of data collected by the AMSR-E instrument on NASA's Aqua satellite.





In this video, NASA's Cryosphere Program Manager, Tom Wagner, shares his perspectives on the 2011 sea ice minimum.

Ice cover throughout the year can affect polar ecosystems, world-wide ocean currents, and even the heat budget of the Earth. During the last 30 years that NASA has been monitoring the ice with satellites, there has been a consistent downward trend, with less and less ice making it through the summer. The thickness of that ice has also diminished. In 2011 Arctic sea ice extent was its second smallest on record.

In 2007—the last time sea ice reached similarly low levels—conditions were ideal for melt. Skies were clear, wind patterns thinned the ice, and warm air temperatures melted the ice. Weather patterns in 2011, by contrast, were typical. This means, NSIDC scientists say, that the ice was thin and spread out before the melting even started in the summer of 2011. nsidc.org