Another branch has appeared in a huge crack on one of Antarctica's
largest ice shelves, and scientists fear it's only a matter of time
before a massive chunk -- potentially containing up to 5200sq km of ice
-- breaks away. If this happens, the ice shelf may become increasingly
unstable and could even fall apart.
Scientists have been closely monitoring the Larsen C ice shelf, located on the east coast of the Antarctic Peninsula, where a large rift in the ice -- now about 180km long -- has been advancing in rapid bursts in recent years. Between the beginning of December and the middle of January alone, the crack lengthened by about 27km. And since 2011, it has grown by about 80km.
Over the past few months, scientists have noticed that the crack has stopped extending in length but has continued to widen at a rate of more than a metre a day. It's already more than 300m wide.
And now, scientists have noticed a worrying development: A new branch has split off from the main rift, about 10km below the tip of the original crack, and has splintered off in the direction of the ocean. The new branch is about 15km long. Altogether, only about 20km of ice now stands in the way of the whole chunk splitting off into the sea.
Researchers from Project Midas, a British-based Antarctic research project based at Swansea University and Aberystwyth University, observed the new crack in satellite images on May 1.
The biggest concern is not whether the chunk will break off -- that seems to be inevitable at this point -- but what will happen after it does. The break will sweep away about 10 per cent of the ice shelf's total area, and scientists have previously speculated that the shelf will become increasingly unstable after this point.
"We have previously shown that the new configuration will be less stable than it was before 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," Swansea University professor Adrian Luckman, a leader at Project Midas, said in a statement.
Scientists have been closely monitoring the Larsen C ice shelf, located on the east coast of the Antarctic Peninsula, where a large rift in the ice -- now about 180km long -- has been advancing in rapid bursts in recent years. Between the beginning of December and the middle of January alone, the crack lengthened by about 27km. And since 2011, it has grown by about 80km.
Over the past few months, scientists have noticed that the crack has stopped extending in length but has continued to widen at a rate of more than a metre a day. It's already more than 300m wide.
And now, scientists have noticed a worrying development: A new branch has split off from the main rift, about 10km below the tip of the original crack, and has splintered off in the direction of the ocean. The new branch is about 15km long. Altogether, only about 20km of ice now stands in the way of the whole chunk splitting off into the sea.
Researchers from Project Midas, a British-based Antarctic research project based at Swansea University and Aberystwyth University, observed the new crack in satellite images on May 1.
The biggest concern is not whether the chunk will break off -- that seems to be inevitable at this point -- but what will happen after it does. The break will sweep away about 10 per cent of the ice shelf's total area, and scientists have previously speculated that the shelf will become increasingly unstable after this point.
"We have previously shown that the new configuration will be less stable than it was before 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," Swansea University professor Adrian Luckman, a leader at Project Midas, said in a statement.
http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=11850335
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