This map shows sea ice extent around Antarctica on September 22, 2013, when ice covered more of the Southern Ocean than at any other time in the satellite record.
This pair of images shows Antarctic sea ice concentrations at the 2008 winter maximum and the 2009 summer minimum compared to the median ice extent from 1979–2000.
Since satellites began monitoring sea ice in 1979, researchers have observed a decline in the average extent of Arctic sea ice in every month of the year.
A spectacular view of sea ice was captured during an Operation IceBridge flight in 2014; the mission surveyed ice at both poles again in 2015, this time simultaneously.