Lengthening and Widening Crack in The West Antarctic Cause For Global Concern

This is no longer just an apparent threat – it’s actually happening – large areas of coastal land will be lost – potential rise in sea levels globally.

Lengthening and Widening Crack in The West Antarctic Cause For Global Concern

Antarctica the southernmost continent on Earth, and the coldest is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. It is the fifth largest continent on Earth almost twice the size of Australia.

Approximately 98 percent of the barren continent is covered by ice with an average thickness of 1.9 km and it covers the entire continent except for the northernmost parts of the Antarctic Peninsula. It is the coldest, driest and windiest continent on Earth with a minimum annual precipitation of 200 mm mostly along the coastline. The coldest recorded temperature ever was −89.2 °C (−128.6 °F).

 Rift in Pine Island Glacier ice shelf, West Antarctica, photographed from the air during a NASA Operation IceBridge survey flight on Nov. 4, 2016. This rift is the second to form in the center of the ice shelf in the past three years. The first resulted in an iceberg that broke off in 2015. Credit: Credit NASA/Nathan Kurtz.
Rift in Pine Island Glacier ice shelf, West Antarctica, photographed from the air during a NASA Operation IceBridge survey flight on Nov. 4, 2016. This rift is the second to form in the center of the ice shelf in the past three years. The first resulted in an iceberg that broke off in 2015,Credit NASA/Nathan Kurtz.

The Transantarctic Mountains divides the continent in two, East and West Antarctica. The portion which is west of the Weddell Sea and east of the Ross Sea is referred to as West Antarctica and the remainder of the desert continent is called East Antarctica.

The Larsen ice shelf, in West Antarctica, which has been under threat of collapse for decades according to scientists, comprises a series of three shelves, north to south, and are called Larsen A, Larsen B, and Larsen C.

Portions of Larsen B collapsed between January 2002 and March 2002 which had been stable for almost 12000 years. Despite its long history, Larsen B had been in trouble resulting from warm currents eating away the underside of the shelf.

It is now Larsen C, the fourth largest ice shelf in Antarctica, which is under observation for some time now by scientists and glaciologists who focus on Antarctica. They have been monitoring the progression of a large crack which has grown to about 30 km in length between 2011 and 2015. Not only has the crack grown in length but has also widened to about 200 meters and growing.

During the intense winter polar night, the progression of the crack was not visible via satellites. Now, with the polar night in Antarctica coming to an end, the crack is once again visible to the team of researchers including scientists and glaciologists.

What has emerged in the latest viewings is nothing short of astounding!

Since last observed in March 2016, the crack has grown in length by 22 kilometers and the yawning width has expanded to 350 meters as reported by researchers from Project MIDAS, a British Antarctic Survey.

What one can conclude from this is that it won’t be too long before a gigantic chunk of Larsen C is lost to the sea, not unlike the losses of Larsen A in 1995 and Larsen B in 2002. The amount of ice that is estimated to be lost would be approximately 6000 square kilometers – a little more than the size of Prince Edward Island, according to an email by O’Leary, a glaciologist at Swansea University and one of the members of MIDAS.

“It’s hard to tell how soon it could break — we really don’t have a good handle on the processes which control the timing of the crack propagation,” O’Leary said. “It’s a lot like predicting an earthquake — exact timings are hard to come by. Probably not tomorrow, probably not more than a few years.”

There are differing views and assessments of the situation by various groups of researchers studying the phenomena. Some are of the opinion that the loss of this mass of ice from Larsen C is not likely to have major consequences on global sea levels.

The MIDAS researchers, however, think that there is a great potential of the consequences being considerably more severe in terms of the rise in global sea levels and the world climate in general.

While the major worry outside of Antarctica is sea-level rise from the glaciers behind Larsen C, “it will also be a shame if the Larsen C ice shelf disappears as well,” said Jansen. “I have spent so much time now looking at the satellite images, and I really love this ice shelf, it would be such a tragic thing to see this thing go.”

“This is really happening,” NASA’s Thomas P. Wagner emphasized to the New York Times. “There’s nothing to stop it now.”

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