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NASA Spots New Crack in Greenland Glacier

Is the Petermann Glacier getting ready to rupture again?

Does this crack spell bad news for the Petermann Glacier? (NASA ICE (Twitter) )
smithsonian.com

Greenland’s ice sheet is a majestic, chilly expanse. But in recent years, it’s been changing, with large hunks of ice splitting off in 2010 and 2012. In recent weeks, scientists have spotted evidence of a worrisome new crack on one of its most famous glaciers. But now, as Chris Mooney reports for The Washington Post, a NASA flyover has provided a better look at this alarming fissure.

Mooney recently reported on the discovery of the crack—an unexpected rupture in the Petermann Glacier that has concerned scientists. Located in northwest Greenland, the glacier is a kind of ice tongue, a tidewater glacier that is sensitive to changes in the water around it. It’s part of the bigger Greenland ice sheet, which covers most of Greenland. The ice sheet is about three times the size of Texas, but thanks to warming ocean and surface temperatures, it’s begun to shrink.

It’s not yet clear why the crack has formed, but thanks to new imagery scientists have confirmed its location. Positioned near the center of the glacier, the crack is close to a long-known fissure on the east side of the glacier. Researchers worry that the new crack could one day join up with the older one, linking them together.

If that happens, it’s bad news indeed. The Petermann Glacier lost a ginormous chunk of ice in 2010 that was four times the size of Manhattan, and another 46-square-mile piece broke off in 2012.

The act of a glacier breaking off into icebergs is called calving, but it’s not as cute as its name might imply. Though glaciers do sometimes produce icebergs as part of normal ice fluctuations, warmer temperatures can cause unusual calving events.

The Greenland ice sheet has suffered tremendous losses in recent years. One 2016 study estimates that between 2011 and 2014 alone, it lost about 270 gigatons of ice, or the equivalent of about 110 million Olympic swimming pools’ worth of water every year, John Abraham reported for The Guardian last year. Scientists think that as waters warm and global climate change continues, Greenland will continue to lose both surface and underwater ice more quickly than other ice sheets. An abrupt melting event could cause a dramatic sea level rise.

The stakes are high for the Petermann Glacier—but NASA’s on the case when it comes to monitoring. The agency’s Operation IceBridge studies changes in the ice sheet through aerial surveys and satellite tracking. After being given coordinates by the Dutch researcher who first spotted the crack on satellite images, Mooney reports, they performed a flyover and confirmed its existence.

It’s still unclear whether the two rifts will connect, why they exist, or what might happen if they combine. But both cracks are a reminder that, like it or not, Earth’s ice is changing—and it’s imperative to learn as much as possible about glaciers while they still exist.

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