Climate Number: 5.8 million square miles
One of Earth’s most dramatic seasonal cycles is the waxing and waning of the sea ice that surrounds Antarctica, the driest, darkest and coldest continent. At its maximum extent at the end of the Southern Hemisphere winter in September, a 6.9 million square mile expanse of ice extends from Antarctica’s shores out into the Southern Ocean. This 6.9 million square mile collection of ice is larger than the solid continent itself, which covers an area of about 5.4 million square miles. By the end of the Southern Hemisphere summer, however, the sea ice has shrunk to about 1.1 million square miles, a difference of about 5.8 million square miles or a 630 percent decrease in area.
For Comparison: 5.8 million square miles of seasonal sea ice is almost enough to cover the lower 48 United States twice over.
Below: Seasonal differences in Antarctic sea ice extent. Image courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder, Colorado.
Seasons: Winter, Spring, Summer, Fall
Sources: The National Snow and Ice Data Center. “All About Sea Ice” Accessed Online 30 April 2010
