Massive iceberg four times the size of London breaks away from Antarctic ice shelf

BE2C2 Report — A massive fissure finally broke and a huge iceberg — one of the largest on record, separated from Antarctica’s Larsen C ice shelf, an event that researchers have been anticipating for months.

In January, scientists with the British Antarctic Survey said the massive iceberg was preparing to calve. Satellite images then revealed a growing fracture 120-mile long.

Researchers estimated the likely break will set free as much as 3,100 square miles of ice, or nearly 2 million acres.

According to the latest images from NASA’s Aqua MODIS satellite, the giant iceberg, about the size of Delaware, broke off from the Antarctic ice shelf sometime between Monday and Wednesday.

January 2017: The dark line creeping across the Larsen C ice sheet suggest a large iceberg is preparing to calve. Photo by the British Antarctic Survey

“We have been anticipating this event for months, and have been surprised how long it took for the rift to break through the final few kilometers of ice,” Adrian Luckman, a researcher at Swansea University, said in a news release.

Luckman is the lead investigator on the MIDAS Project, a team of researchers in the U.K. studying the Larsen C ice shelf.

At 2,239 square miles, the breakaway iceberg is gigantic. Its size is roughly four times the size of the city of London, and its volume is twice that of Lake Erie. It weighs more than 1 trillion metric tons and, with the iceberg now gone, the Larsen C ice shelf is now 12 percent smaller.

Its impact on sea level rise or on global temperature remains a subject of study and intense debates among the scientists community.

The disintegration of ice shelves don’t directly contribute to sea level rise, as they are floating in the ocean water already, say some experts. But because they act as a buffer between the ocean and grounded glaciers, scientific models suggest their losses can accelerate glacial melting farther inland.

Kelly Brunt, a glaciologist at the University of Maryland and NASA’s Goddard Space Flight Center, told PBS, if the glaciers in West Antarctica all dropped into the water, global sea level would rise by more than 15 feet.

While the newly separated iceberg currently remains a single entity, it is likely to break into fragments in the future and may not affect sea level rise.

“Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters,” MIAS researchers wrote in a blog post.

Though the Larsen C ice shelf will regenerate to some extent, most researchers agree the loss of the iceberg will leave the ice shelf significantly less stable than it was before the break.

“The calving of this large iceberg could be the first step of the collapse of Larsen C ice shelf, which would result in the disintegration of a huge area of ice into a number of icebergs and smaller fragments,” David Vaughan, a glaciologist and the director of science at the British Antarctic Survey, said earlier this year.

Ice shelves are found where glaciers meet the ocean and the climate is cold enough to sustain the ice as it goes afloat. Located mostly around Antarctica, these floating platforms of ice a few hundred meters thick form natural barriers which slow the flow of glaciers into the ocean and thereby regulate sea level rise.

In 2002, Larsen C’s neighbor, the Larsen B ice shelf, disintegrated in the wake of a similarly dramatic breakaway — in six weeks. The piece that broke off was the size of Rhode Island.

The Larsen Ice Shelf of Antarctica is named for a famous 19th century Norwegian explorer. And it is disappearing, section by section, identified by letters.

Larsen A disintegrated in 1995.

Scientists believe warm ocean currents and rising air temperatures are weakening glaciers from the top and the bottom.

The consensus among scientists is that man-made carbon emissions have a sizable warming effect on Earth’s atmosphere and climate. This larger reality — the global carbon cycle and its climatological impacts — consists of thousands of inputs and outputs, interrelated by specific cycles. Predicting how larger atmospheric carbon levels will affect Earth’s many cycles and systems — whether meteorological, oceanic, ecological — is the focus of today’s climate scientists.

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