By Sid Perkins
Ocean-floor sediments drilled from Antarctic regions recently covered by ice shelves suggest that those shelves were only 2,000 years old. This finding could compel scientists to reassess whether the current destruction of polar ice is due primarily to human-caused global warming.
In the early 1990s, part of the ice shelf atop the Prince Gustav Channel, which separates the Antarctic peninsula and James Ross Island, broke apart. In the area formerly covered by the shelf, the channel’s water depth is between 600 and 800 meters. Scientists collected sediment cores 5 to 6 m in length from the ocean floor in February and March 2000.