On the glacial plains of East Antarctica, change comes slow.
The extreme sub-zero temperatures of the area mean that the ice shelves are relatively stable. That’s what makes the last 15 years so odd. Since the year 2000, over 8,000 crystal blue lakes have appeared on the surface of the coastal Langhovde Glacier – and it has some experts worried. A similar thing has been observed before, you see – in Greenland’s rapidly disintegrating ice sheets. In the case of Greenland, these rapidly-appearing meltwater lakes signified something more grim – namely the loss of over 1 trillion tons of ice between 2011 and 2014.
In a recent study, researchers outline the possibility that the azure lakes dotting the surface of the Langhovde Glacier are themselves a threat to ice shelf stability. Similar to the case in Greenland, the supraglacial lakes appear to have been draining down into cracks in the ice, weakening the glacier from the inside. The research team believe that this type of drainage event was partly to blame for the collapse of the Larsen-B ice shelf in 2002.
If the sight of these turquoise lakes is cause for concern, their sudden disappearance would be even worse. In some cases, supraglacial lakes can drain all at once – there’s been recorded incidents of freshwater currents flowing out of icebergs as if they were tapped. When freshwater dumps out in a rush towards the ocean, it can result in swirling whirlpools of mixed water that can further disrupt the stability of glacier fronts.
The appearance of the lakes has been strongly linked to surface air temperatures. “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,” said Stewart Jamieson, one of the authors of the study. He believes that although the lakes aren’t a critical threat in their current state, their size and frequency are only expected to grow if climate trends continue.
All images sourced from NASA.