Animation of the disappearing North Pole (2007)

The animation shows changing sea ice extent and concentration from 12 March to 24 September 2007. Credit U.S. National Ice Center (NIC) via the ESA

At the north pole, the area covered by ice reaches it's maximum in March. The minimum occurs in September. As the figure below shows, both the winter maximum and summer minimum have been dropping over the last 3 decades. In 2006 the maximum ice extent was the lowest on record. This year's summer melting was dramatic even when taking account of the long term trend.



Time series of the difference in ice extent in March (the month of ice-extent maximum) and September (the month of ice-extent minimum) from the mean values for the time period 1979-2007. Based on a least squares linear regression, the rate of decrease for the March and September ice extents was 2.8% per decade and 11.3% per decade, respectively. (image courtesy of NOAA)