Get Out the Lifeboats! Antarctica Is Melting

IF THE EARTH GETS WARMER, WILL THE ICE CAPS melt? That's a matter of hot debate among scientists who worry about possible climatic change. The Antarctic ice sheet alone is larger than the continental U.S. and holds a mass of water that if melted would raise world sea levels by about 60 m (200 ft.).

Coastal residents could take comfort in the prevailing view that Antarctica hasn't thawed for 14 million years, but that view is being challenged. A report in Nature suggests large portions of the ice cap may have melted just 3 million years ago.

The evidence centers on sea-plankton remains found in the Transantarctic Mountains at altitudes where no sea should have been. By measuring the age of nearby volcanic ash, a team led by Peter Barrett at Victoria University of Wellington, New Zealand, concluded that the whole area was probably flooded during the mid-Pliocene epoch -- when temperatures were only a few degrees warmer than today.