Sea levels may rise after huge iceberg breaks off in Antarctica

By Reuters   July 17, 2017 | 11:42 pm PT
The incident could trigger new ice cracks and cause even more icebergs to break off.

NASA has reported that an enormous iceberg about the size of the U.S. state of Delaware split off from Antarctica's Larsen C ice shelf between July 10 and 12. 

Ice shelves are the floating parts of glaciers which act as a support mechanism. In a stable glacier-ice shelf system, the glacier's downhill movement is offset by the buoyant force of the water at the ice shelf front.

The system is destabilized when warmer temperatures melt both the surface and underside of the ice shelves, this eventually leads to calving. However, collapsed ice shelves do not directly contribute to rising sea levels because they are floating.

Once the ice shelves are calved, the buoyant force that previously offset glacier flow is gone, and then glaciers can slide into the ocean, which would rapidly affect sea levels.

"The Antarctic Peninsula has been one of the fastest warming places on the planet throughout the latter half of the 20th century. This warming has driven really profound environmental changes, including the collapse of Larsen A and B," said Dan McGrath, a glaciologist at Colorado State University who has been studying the Larsen C ice shelf since 2008.  

"But with the rift on Larsen C, we haven't made a direct connection with the warming climate. Still, there are definitely mechanisms by which this rift could be linked to climate change, most notably through warmer ocean waters eating away at the base of the shelf," he added.

Experts say the remaining 90 percent of the Larsen C ice shelf is held in place by the Bawden Ice Rise to the north of the rift and the Gipps Ice Rise to the south, therefore the ice shelf is unlikely to collapse in the near term.

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