Researchers from the KU Leuven or University of Leuven, a Dutch-speaking university in Leuven, Flanders, Belgium, have concluded that East Antarctica is now considered vulnerable to climate change. What they discovered is that the East Antarctic ice sheet once thought to be highly stable, now melts due to a strong wind that brings warm air and blows away the snow leaving dark blue ice to absorb more solar heat and melting the ice sheet surface.
Ku Leuven University reports:
Through a unique combination of field work, satellite data and a climate model, the researchers were able to explain why some parts of the East Antarctica ice shelves are melting so rapidly. This is because the strong and persistent wind transports warm, dry air to the region, and blows away the snow. This darkens the surface, which subsequently absorbs more of the sun’s heat. The result is a local warmer microclimate with a few literal ‘hotspots’. Because the ice shelf is floating in the ocean, its melting does not immediately contribute to sea level rise. However, the ice shelves around Antarctica are extremely important for ice sheet stability, because they hold back the land ice. If the ice shelves collapse, this land ice ends up in the ocean and consequently sea level will rise.
Part of the research conducted by Lenaerts and Lhermitte focused on a mysterious crater that was spotted on the King Baudoin ice shelf. “At the time, the media reported that it was probably a meteorite impact crater”, Lenaerts says. “My response was: in that area? Then it’s definitely not a meteorite; it’s proof of strong melting.”
In January 2016, the researchers visited the crater and discovered that it was a collapsed lake, with a moulin – a hole in the ice- which allowed the water to flow into the ocean. Lhermitte: “That was a huge surprise. Moulins typically are observed on Greenland. And we definitely never see them on an ice shelf.” Moreover, the researchers discovered that there were many meltwater lakes hidden under the surface of the ice, some of which were kilometres across. Underwater video images provide a clear image of the amount of meltwater present in the area.
View inside moulin showing the drainage of meltwater on the Roi Baudouin ice shelfFrom the study abstract.
Surface melt and subsequent firn air depletion can ultimately lead to disintegration of Antarctic ice shelves1, 2 causing grounded glaciers to accelerate3 and sea level to rise. In the Antarctic Peninsula, foehn winds enhance melting near the grounding line4, which in the recent past has led to the disintegration of the most northerly ice shelves5, 6. Here, we provide observational and model evidence that this process also occurs over an East Antarctic ice shelf, where meltwater-induced firn air depletion is found in the grounding zone. Unlike the Antarctic Peninsula, where foehn events originate from episodic interaction of the circumpolar westerlies with the topography, in coastal East Antarctica high temperatures are caused by persistent katabatic winds originating from the ice sheet’s interior. Katabatic winds warm and mix the air as it flows downward and cause widespread snow erosion, explaining >3 K higher near-surface temperatures in summer and surface melt doubling in the grounding zone compared with its surroundings. Additionally, these winds expose blue ice and firn with lower surface albedo, further enhancing melt. The in situ observation of supraglacial flow and englacial storage of meltwater suggests that ice-shelf grounding zones in East Antarctica, like their Antarctic Peninsula counterparts, are vulnerable to hydrofracturing7.
x YouTube VideoNational Science Foundation Report Offers Guidance on How to Safely Explore Vast Aquatic Systems Buried Under Antarctic Ice
May 31, 2007
The National Science Foundation (NSF) should work within the environmental framework of the international Antarctic Treaty system to develop a global scientific consensus on minimally disruptive ways to investigate one of the "last unexplored places on Earth"--a unique system of lakes, and the aquatic systems that may connect them, buried thousands of meters under the Antarctic ice sheet--according to a newly released report.
To avoid contaminating these lakes and other features, which scientists have only recently discovered and which have been cut off from the outside world for millions of years, the report calls for NSF to work with international scientific organizations and Treaty signatories to develop a management plan for any potential exploration efforts and, as part of that plan, "ensure that the environmental management of subglacial environments is held to the highest standards."
An artist's cross-section of Lake Vostok, the largest known subglacial lake in Antarctica. Liquid water is thought to take thousands of years to pass through the lake, which is the size of North America's Lake Ontario.