The Arctic's oldest, most robust sea ice has devolved into a pathetic shell of its once-grand self.

A new two-minute video from the American Geophysical Union, a leading earth sciences organization, depicts the dramatic shrinking of the toughest Arctic sea ice over the last 35 years, since 1984. (Reliable satellite observations began in the late 1970s).

The oldest ice, which is four or more years old and most resistant to melting, is shown in white. This ice once froze over the vast Arctic basin. Today, however, just thin wisps of the old ice remain north of Greenland and the Canadian Arctic Archipelago. Read more...