While Antarctic scientists have been documenting that ice shelves are dropping from Antarctica at a rate that is faster than expected. The Nansen Ice Shelf is probably the next giant chunk of ice to fall into the ocean. A huge crack has formed, weakening its connection to the contenent.
Nansen is 600 square miles, roughly twice the size of Manhattan Island. It was spotted by the United States Geological Survey’s (USGS) Landsat 8 satellite. The Nansen’s link to land is becoming dangerously weak.
An ice shelf is simply a floating extension of an ice sheet.
“The front of Nansen Ice Shelf… looks ready to calve off into a tabular iceberg,” wrote Ryan Walker, a researcher at NASA Goddard, on a blog for NASA’s Earth Observatory. “There’s a huge crack, miles long and sometimes over a hundred yards wide, which runs more or less parallel to the front of the ice shelf.”
So what is the significance of the Nansen Ice Shelf collapsing into the sea?
The Antarctic coastline is 75% ice shelves, meaning that when Nansen collapses, it will reduce the ice shelf coverage by just 0.1%. Nansen isn’t even a “major” ice shelf like the Ross Ice Shelf which is roughly 108,000 square miles.
While the ice shelves are anchored to land, their collapse does not actually affect sea level. Because they are already floating on the water their collapse does not cause much harm.
But the ice shelves to serve another purpose. They barricade the glaciers behind them. Once the ice shelf is gone, the glaciers start to move up to ten times faster toward the sea.
Larsen-A in the Antarctic Peninsula collapsed in 1995, followed by Larsen-B in 2002. Larsen-C, which is 2.5 times the size of Wales, is treading on thin ice. Nansen, which is “fed” by the Priestly and Reeves Glaciers and backsup against the peculiar-looking Drygalski Ice Tongue, is looking decidedly wobbly: Two years ago, the crack was barely visible, whereas now it spans almost the entire length of the ice shelf.
