A study published in Nature Climate Change on Monday provided a new theory for how a mysterious “crater” formed in East Antarctica. And it’s looking like weather in the region may be the cause, rather than a meteorite impact as previously thought.
The crater is located on the King Baudouin ice shelf. It is a huge 2 kilometers (1.2 miles) wide, leading scientists to originally think a meteorite had slammed into the region back in 2004.
But now, a team of researchers from the Netherlands, Belgium, and Germany thinks wind may be the cause. Using a combination of field work, satellite imagery, and climate models, they say strong and constant winds may be carrying warm and dry air into the region, blowing away the snow.
As a result, the surface was darkened, absorbing the Sun’s rays more easily, and forming localized “hot spots”. This would have melted the ice, forming a lake on top of the ice shelf that eventually collapsed, leaving the circular crater-like shape behind. Water would have flowed into the ocean through a hole in the ice, called a moulin.
“The build-up of pressure on the lake, which will have become so big and full of water, caused it to drain or collapse under the surface,” study author Jan Lenaerts at Utrecht University in the Netherlands told New Scientist.
The researchers said they had found other lakes under the surface that indicates this has happened before. It suggests East Antarctica is much more vulnerable to climate change than predicted, with the ice shelves melting faster than previous estimates. The ice shelves hold back the ice on the ice sheet, so if they collapse, more ice falls into the ocean, and sea levels rise.
“The amount of meltwater differs immensely from year to year, but it clearly increases during warm years,” study author Stef Lhermitte from the Delft University of Technology said in a statement.
“[A previous study] indicated that West Antarctica is extremely sensitive to climate change. But our research now suggests that the much larger East Antarctica ice sheet is also very vulnerable.”
For more information, check out this interactive web page from the researchers.