Global Warming

Collapsing Beauty: Image of Antarctica's Larsen Ice Shelf

An expansive new image shows the changes in Antarctica's Larsen Ice Shelf since the mid-1980s.

The story is one of retreat, and the ice continues to crumble. A growing crack in a portion of the ice shelf called Larsen C is poised to free an iceberg the size of Delaware from the continent.

Larson C isn't visible in the new satellite image, which focuses on two more northerly portions of the sheet, Larsen A and Larsen B. Ice shelves are floating mattresses of ice that form from the outflow of the glaciers that creep slowly across the Antarctic continent. The Larsen Ice Shelf is on the northeast coast of the Antarctic Peninsula along the Weddell Sea. It was named for the Norwegian explorer Carl Anton Larsen, who explored parts of it in 1893 by ship and ski.

Since 1995, the Larsen Ice Shelf has lost 75 percent of its mass, according to the National Snow and Ice Data Centre (NSIDC). In 1995, a 579-square-mile (1,500 square kilometres) chunk of Larsen A broke off from the ice shelf, according to NASA's Earth Observatory. In 2002, an even larger portion of Larsen B — 1,255 square miles (3,250 square km) crumbled away. While calving events are normal, collapses of this magnitude have only been seen in the last 30 years, according to the NSIDC.

The collapse of floating ice doesn't raise sea levels, but a 2004 study by NSIDC researchers found that in the wake of Larsen B's 2002 collapse, the land-based glaciers that feed the ice sheet have accelerated their flow toward the sea. This speedy flow of ice does have the ability to raise sea levels.