Supraglacial lakes, made of meltwater, are putting East Antarctica’s ice sheets in danger.
Ice sheets are slabs of glacier ice covering at least 20,000 square miles of land. When global temperatures rise, lakes form on the surface of the ice sheets, which scientists believe are a major factor in the disintegration of the world’s glaciers.
British researchers Emily Langley, Amber Leeson, Chris Stokes and Stewart Jamieson studied the lake formation in Antarctica and published a study in Geophysical Research Letters about their findings.
Using satellite imaging and meteorological data, the authors discovered that, between 2000 and 2013, nearly 8,000 meltwater lakes had formed on the Langhovde Glacier in East Antarctica.
Before the study, Antarctica, which contains the most ice in the world, was thought to be impervious to rising global temperature changes.
"There’s not a huge amount of change, it’s very, very cold, and so, it’s only very recently that the first supraglacial lakes, on top of the ice, were identified," says glaciologist Stewart Jamieson from Durham University.
While beautiful, the supraglacier lakes pose a danger to Antarctica’s ice slabs.
The meltwater lakes can flow into rivers that erode the ice below, or even feed directly into
the ocean at the base of a glacier, creating tornado-like turbulence that can cause further glacial melting.
"It's not just lakes forming and refreezing in the winter," says study co-author Amber Leeson. "They're forming, draining and feeding into a wider 'subglacial' hydrological network. And no one has really thought of that before in East Antarctica."
When ice melts, it can disintegrate quickly, leading to massive increases in sea level. It’s happened before: Greenland’s ice sheets lost a trillion tons of ice between 2011 and 2014 after meltwater lakes began to appear.
“What we find is that the appearance of these lakes, unsurprisingly, is correlated directly with the air temperature in the region, and so the maximum number of lakes, and the total area of the lakes, as well as the depth of the lakes, all of these things peak when the air temperatures peak,” says Jamieson.
Global temperatures are on the rise; most of the 8,000 Antarctic meltwater lakes formed in the summers of 2012 and 2013, when Antarctica experienced an abnormal increase in temperature.
"The warm years are expected to become more frequent in the future, so we might expect to see even more lakes and even deeper lakes in the future," says Leeson.
July 2016 was confirmed as the world’s hottest month on record. If ocean temperatures continue to increase and the glaciers continue to melt at the current rate, sea levels could rise by as much as 86 centimeters by 2100, increasing the risk of flooding, coastline erosion, and habitat loss for fish and wildlife.