13 july 2017

2,240-square mile iceberg from Larsen C Ice Shelf is now spiraling in the Weddell Sea. What's next?

By Pakalolo, The Daily Kos, 2017/07/13

“Climate change is a long-term trend. The peninsula has been warming for decades. Warm water is the main driver now (in Antarctica as a whole). If warmer air is sufficient to melt the surface, then the ice shelves will break up and sea level rise from Antarctica will be enormous.” Eric Rignot

There are a lot of new discoveries about Antarctica’s peninsula lately that are raising worrying concerns about the region. The land area is greening rapidly giving invasive plants and the common housefly (most of which have been brought to the area by tourists and scientists equipment and/or clothing) a foothold which will upend a very delicate and fragile eco-system. In addition, Hairdryer winds a/k/a Foehn winds, has an effect on the ice that pushes east from the Peninsula out over the Weddell Sea. These warm winds produce great ponds of brilliant blue melt water at the surface. It is these blue ponds that caused the rapid collapse of Larsen B ice shelf. Scientists do not believe, at this point in time anyway, that Larsen C will share the same fate as it is larger and colder. Scientists will be studying the ice shelf in the years and decades ahead.

Brian Kahn of Climate Central reports on what’s next for the Larsen C ice shelf after the final break was detected by NASA’s Aqua satellite and released a trillion ton iceberg into the waters of Antarctica’s Weddell Sea. An iceberg that we should refer to going forward as “Exxon Knew”.

"The Larsen C crack had been growing since 2010 largely due to natural causes, according to most researchers. When it finally broke through sometime between Monday and Wednesday, it reduced the Larsen C ice shelf to its smallest size on record. The ice shelf was the fourth-largest ice shelf in the world, but following the calving event that cleaved off more than 12 percent of its area, it has been knocked down to fifth in the rankings.

"Ädrian Luckman, a scientist who has been watching the iceberg for years with Project MIDAS, said it would take months or years to document the health of the remaining ice shelf.

"Though it has lost 2,240-square miles, Larsen C still spans roughly 15,000 square miles. That could make it more resilient than the neighboring Larsen B ice shelf that collapsed due a warm spell following a major calving event in 2002, but it’s not a guarantee.

"Bethan Davies, a glacier researcher at Royal Holloway, University of London, said one of the first things that researchers will look at is the “stress regime” that losing so much ice puts on the rest of the ice shelf. It’s akin to standing up against a teetering pile of books. If you shift your weight or put less effort to propping up the pile, it might start to wobble differently, a few books might fall off or the whole thing could topple over."

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