Ice shelf nears detachment off Antarctica

(UPDATED) A fissure has damaged an ice shelf in Antarctica, signaling the potential sea level rise if other ice shelves leave glaciers vulnerable.

(photo courtesy of John Sonntag, NASA)

An estimated 175-kilometer crack with a maximum width of two miles threatens the Larsen C ice shelf. While it will not contribute much to sea level rise, it is a sign of how climate change will affect the glaciers in the future.

The rupture only has thirteen kilometers left to carve before the 5,000 square kilometer iceberg floats away to the sea. Ten percent of the Larsen C ice shelf is expected to tear away from it.

(photo courtesy of Project Midas)

Fears of sea level rise originate back in 1995 and 2002, when the Larsen A and Larsen B ice shelves collapsed and allowed the glaciers behind them to accelerate. (READ: Unstable Antarctica)

Glaciers, ice shelf, calving

What's happening in Larsen C is called "ice calving."

Ice calving is a natural phenomenon where the ice shelf separates itself from the glacier as the latter moves or expands. Glaciers are dense ice formations on land areas that flow outward, thus creating the floating expanse of ice called ice shelf.

Ice shelves prevent glaciers from floating away to the sea. Naturally, ice shelves melt during summer and reforms back to its normal state with the help of its glacier. It does not contribute to sea level rise since it floats on water.

Only the glacier, an inland body of ice, can dramatically increase sea level since it holds large amounts of water internally.

According to UK-based Antarctic research Project Midas, "Although the rift length has been static for several months, it has been steadily widening, at rates in excess of a meter per day."

Caused by global warming?

The ten-man team of Project Midas rebuffed claims that climate change caused the calving. "Although the general southward progression of ice shelf decay down the Antarctic Peninsula has been linked to a warming climate, this rift appears to have been developing for many decades, and the result is probably natural."

Chris Borstad, an Associate Professor of Snow and Ice Physics from the University Centre in Svalbard, said that there are no conclusions yet if climate change is relative to the rift in Larsen C ice shelf.

"It is possible, however, that warmer ocean currents may have been melting the bottom of the ice shelf, which may have made it easier for this crack to begin growing in the first place. This would be a plausible connection to climate change, but we have to do more research to know for sure," he said in a Reddit post.

Speculations on effects of climate change rose after 8,000 meltwater lakes formed from 2000 to 2013 every summer in East Antarctica. Durnham University's study concluded that lakes either "refreeze, drain vertically through the ice, or drain laterally via surface channels."

Similarly, it is a natural event that got worse due to climate change. These lakes lasted longer in the summer and had the tendency to fracture the ice.

Totten Glacier in East Antarctica is also eroding underneath due to warm ocean water. It is expected to contribute two meters in sea level rise. (READ: Totten Glacier risks sea level rise)

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