Antarctica's about to give the world one of its biggest ever icebergs

James Marshall
Июля 7, 2017

Recent monitoring of the Copernicus Sentinel-1 radar pair in the European Space Agency's CryoSat mission revealed that the crack is now about 200 kilometers long (124 miles), leaving a mere 5 kilometers (3 miles) between the end of the fissure and the ocean.

When it eventually gives way, one of the largest icebergs on record will be set adrift.

Scientists have closely monitored a rift in Larsen C that has grown during the past few years that is carving out a 1,930-square mile section of floating ice.

Antarctica has lost ice shelves earlier but none as huge as this one. The iceberg's outer end is moving at the highest speed ever recorded on this particular ice shelf.

No one knows when it will break off - it could be any moment, a matter of days or hours until it officially breaks off.

How big will the Larsen C iceberg be?

"Using information from CryoSat, we have mapped the elevation of the ice above the ocean and worked out that the eventual iceberg will be about 190 metres thick and contain about 1,155 cubic kilometres of ice", said Noel Gourmelen from the University of Edinburgh in the UK. Or put another way, it's enough to cover all 50 states in 4.6 inches of ice, allowing you to skate coast-to-coast and take victory laps around Hawaii and Alaska. The portion of the iceberg that lies under the water's surface could have a depth as low as 210 meters / 689 feet.

Where will the iceberg go after breaking off? Whole or in pieces, ocean currents could drag it north, even as far as the Falkland Islands.

Will the iceberg breaking off the Larsen C ice shelf be harmful in anyway? "If so it could pose a hazard for ships in Drake Passage", she said.

"It could, in fact, even calve in pieces or break up shortly after", explains Anna Hogg from the University of Leeds.

To track the iceberg's progress, ESA will use data from its CryoSat and Sentinel-1 satellites.

'Computer modeling suggests that the remaining ice could become unstable, and that Larsen C may follow the example of its neighbour Larsen B, which disintegrated in 2002 following a similar rift-induced calving event'.

Moreover, he said, Trump's decision to pull out of the 2015 worldwide climate change agreement and cut environmental budgets will thwart future research around global warming.

Larsen C is not the first major iceberg to break off. "Of course this is due to climate warming in the peninsula", Eric Rignot, a NASA and University of California Irvine expert on Antarctica, told the Washington Post in an email.

A November 10, 2016 aerial photo released by NASA shows a rift in the Antarctic Peninsula's Larsen C ice shelf. Most of that water is now locked up in the Greenland as well as the East and West Antarctic ice sheets. But Helen Amanda Fricker, a professor at the Scripps Institute of Oceanography, wrote in the Guardian that "hyping research results to sound like climate change, when they are just improved understanding of natural behaviour [sic], is misleading".

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