Larsen C ice crack continues to increase

Larsen C ice crack continues to lengthen

A tabular iceberg one-quarter the size of Wales may soon break off the Larsen C Ice Shelf in Antarctica as a crack in it continues to lengthen, climate scientists have warned.

Since January 1, the crack in the Larsen C Ice Shelf has extended further 10 kilometers, and scientists have warned that it would free a massive tabular berg if the rift propagates merely 20 kilometers.

Researchers from Aberystwyth and Swansea universities and the British Antarctic Survey (BAS) said that a fresh study suggested that the crack has already extended for some 195 kilometers. But it is hard to precisely predict how long it will take for the 5,000 sq. km. ice block to finally break free.

A separate crack recently forced BAS to declare closure of its Halley VI Research Station on a floating Brunt Ice Shelf which sticks out into the Weddell Sea. The crack has reached within four miles of the facility.

Prof. Adrian Luckman said in a statement, “Although you might expect any extension to hasten the point of calving, it actually remains impossible to predict when it will break because the fracture process is so complex. My feeling is that this new development suggests something will happen within weeks to months…”

The lengthening rift in the 350m-thick floating ice shelf on the Antarctic Peninsula’s eastern side was first detected by the European Union’s Sentinel-1 satellite system.

In the past few decades, around a dozen massive ice shelves, including Jones Channel, Larsen Inlet, Larsen A, Larsen B, and Prince Gustav Channel, have either disintegrated or lost substantial volume.

Scientists affiliated with a group that has been tracking the ice melt in this area, known as Project MIDAS, say the iceberg could measure 5,000 square kilometers, or 1,930 square miles. Scientists are worried that the calving event — which refers to the breaking off of the iceberg from the ice shelf — could speed up the disintegration of the broader shelf and land-based ice that lies behind it.

"When it calves, the Larsen C Ice Shelf will lose more than 10 percent of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula," researcher Adrian Luckman wrote in a blog post.

"We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbor Larsen B, which disintegrated in 2002 following a similar rift-induced calving event," Luckman wrote.

"We expect that the iceberg will break free within the next few months, although it's hard to be certain about timing," Martin O'Leary, a researcher at Swansea University in the U.K. who studies the Larsen C Ice Shelf as part of the MIDAS team.

When it calves, the Larsen C Ice Shelf will lose more than 10% of its area to leave the ice front at its most retreated position ever recorded; this event will fundamentally change the landscape of the Antarctic Peninsula. We have previously shown that the new configuration will be less stable than it was prior to the rift, and that Larsen C may eventually follow the example of its neighbour Larsen B, which disintegrated in 2002 following a similar rift-induced calving event.

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