The World’s Largest Iceberg Just Broke Off Of Antarctica



A massive slab of ice, nearly six times the size of New York City, has broken off of an ice shelf in Antarctica, creating what is now the largest iceberg in the world, scientists recently announced.

The iceberg, dubbed A-76, was spotted breaking away from the Ronne Ice Shelf in the Weddell Sea by a researcher with the British Antarctic Survey on May 13. The separation was confirmed by the U.S. National Ice Center (USNIC) using satellite images.

The long block of ice is roughly 1,668 square miles in size, spanning 89 nautical miles on its longest axis and 14 nautical miles on its widest axis, according to the USNIC. (In comparison, the entirety of New York City’s land area is about 303 square miles.)

Christopher Readinger, the lead analyst for the USNIC’s Antarctic team, said the break was “not unexpected … but it did come out of the blue, sort of.”

That’s because icebergs breaking off of larger ice masses — or “calving,” as experts call it — is generally unpredictable, and crevasses aren’t always an indicator that something’s about to happen, Readinger told HuffPost on Thursday.

“We could watch them for years and they won’t do anything and elsewhere there will be this perfectly solid ice shelf that will suddenly collapse unexpectedly,” he said.

Ice calving, even at relatively large sizes, is not necessarily anything to be concerned about, so long as the ice sheet is considered to be in overall balance, which is when the amount of ice gained through snowfall is equal to the amount of ice lost through melting and iceberg calving, according to NASA.

Like Readinger, Ted Scambos, a research glaciologist at the University of Colorado at Boulder, told Reuters that the breaking off of A-76 is likely not linked to climate change. Scambos also said it won’t raise the ocean level when it melts, since the ice was already in the water as part of a floating ice shelf.

As for what happens next to A-76, Readinger said it will eventually melt and break apart. The question is, when and where?

A fragment of one formerly massive iceberg, B15, that calved around 20 years ago is still hanging around; another iceberg has been stopped in the same spot for the last 33 years, he said.

A-76 could also travel northward, out to sea, and break apart with the help of waves, warming temperatures and meltwater on the ice’s surface that will percolate downward and fracture the ice, Readinger said.

For now, A-76 is the world’s biggest iceberg, taking the first place title away from the A-23A iceberg, which is about 1,498 square miles and also located in the Weddell Sea, according to the European Space Agency.

The icebergs in this region of the world are traditionally named according to the Antarctic quadrant where they originated. “A” represents the Weddell and Bellingshausen Seas, and 76 indicates that it is the 76th iceberg tracked by USNIC in that quadrant. An iceberg is given a sequential letter if it breaks off from a larger named mass. So, A-23A was first part of the glacier A-23, which split from Antarctica’s Larsen C ice shelf in 2017.

The Ronne Ice Shelf is the second largest in Antarctica. It was named after Edith “Jackie” Ronne, who was the first American woman to visit Antarctica as part of an exploration expedition in the 1940s. 



Source link Science

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