Collapse of the Larsen-B

April 08, 2002


Provided by: European Space Agency
Summary author: Jim Foster

In the past two decades or so, a number of huge ice chunks have snapped off of glaciers in the Antarctic. The most recent episode of ice disintegration, while it happened in Antarctica, actually occurred north of the Antarctic Circle. A portion of the Larsen Ice Shelf (Larsen B), which used to sit at about 66 degrees S latitude, shattered and separated from the eastern side of the Antarctic Peninsula in early March. The above photograph was taken by Helmut Rott for the European Space Agency (ESA) and shows part of the gargantuan separation. It's believed that this was the largest such collapse in at least 30 years. An estimated 1,250 square miles (3,250 square km) of the Larsen Ice Shelf, about the size of Luxembourg or the state of Rhode Island, has slipped into the Weddell Sea since early February. This fractured ice has resulted in the formation of thousands of icebergs.

Since ice shelves are already floating, they're in equilibrium with the sea. For the same reason, when ice cubes in your favorite beverage melt, the level of the liquid in your glass doesn't change. However, if the ice shelves disappear, glacial ice that's not now floating could pour into the sea, which would then raise the sea level. Fortunately, because the Larsen Ice Shelf is anchored to a peninsula rather than the bulk of the continent, there's not a massive ice sheet now poised to rush toward the Weddell Sea.

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