Giant Crack in Antarctica's Larsen C Ice Shelf Grew 11 Miles in Just 6 Days

Larsen C ice shelf
The Larsen C ice shelf in December 2016. NASA/John Sonntag

A huge crack in one of Antarctica's largest ice shelves has grown by another 11 miles, leaving an area of ice a quarter of the size of New Jersey hanging on by a section that is only eight miles long. When it eventually breaks away, it will become one of the largest icebergs ever recorded, scientists say.

Scientists with Project Midas, a U.K. based Antarctic research group, have been observing the growing rift on the Larsen C Ice Shelf for the last two years. In January, they said the crack had grown significantly and it was connected to the main ice shelf by 12 miles.

The crack continues to grow. In May, the team said another crack had appeared, branching off from the main fissure. "A new branch of the rift has been initiated," Adrian Luckman, head of Project Midas, said in a statement. "This is approximately 10km [6 miles] behind the previous tip, heading towards the ice-front."

In the latest update, scientists said the main rift has now turned towards the ice-front (the seaward edge of an ice shelf). This suggests that the time of calving—where icebergs break away—is "very close."

In an email to Newsweek , Project Midas scientist Martin O'Leary said: "[Until now] the rift has been growing more or less parallel to the ice front, so the amount of ice connecting the berg to the shelf has been more or less constant. However, this time around the rift has curved towards the front, so there's now only 13km [eight miles] remaining."

Larsen C ice shelf
The Larsen C ice shelf. This image shows the 111-mile rift that grew over two years, before a Delaware-sized iceberg broke away. John Sonntag/NASA
Larsen C
Larsen C ice shelf. Image shows the latest growth of the rift, as of May 31, 2017. Project Midas

The team said the calving event now seems inevitable. "The rift has now fully breached the zone of soft 'suture' ice originating at the Cole Peninsula and there appears to be very little to prevent the iceberg from breaking away completely," they said in a statement.

Calving events are the result of natural geophysical processes not linked to climate change.

Researchers at Project Midas will continue to monitor the rift. When it eventually breaks off, the Larsen C ice shelf will lose over 10 percent of its area, leaving the ice front at "its most retreated position ever recorded." The resulting iceberg will measure 3,100 square miles.

"This event will fundamentally change the landscape of the Antarctic Peninsula," the team said. "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 after a similar rift-induced calving event."

The Larsen C ice shelf sits at the edge of West Antarctica. It is 217 miles thick and holds back the flow of glaciers feeding into it. Its former neighbours, Larsen A and B, both collapsed in the last 20 years. Larsen B disintegrated after a calving event similar to the one currently being monitored.

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