The emergence of around 8,000 blue lakes on East Antarctica’s ice sheets has captured the attention of scientists who are concerned about the related implications. This is documented in a paper published in Geophysical Research Letters.
The blue lakes in question are notorious because of the alleged destruction with which they have been associated lately: recent studies show that one trillion tonnes of ice have been lost from Greenland from 2011 to 2014 because of the appearance of these water bodies on its ice sheet; the lakes might possibly be the result of climate change. Could the same happen to Antarctica?
After UK scientists examined satellite images of East Antartica’s Langhovde Glacier together with meteorological data from the region, they detected the presence of around 8,000 such lakes having formed between 2000 and 2013. Some of these water accumulations, called supraglacial lakes, are thought to be leaking into floating ice underneath – if this is indeed true, the whole ice shelf might have to bear the bitter consequences thereof.
East Antarctica is not normally in the spotlight in talks pertaining to global warming’s disastrous consequences because researchers have deemed it to be less vulnerable. As a consequence, research endeavours have been focused on other parts of the continent. It now appears that the ice sheet of East Antarctica will need more attention. Already, scientists are anxious because of the lack of relevant knowledge with respect to the effects of supraglacial lakes there.
“[East Antarctic is] the part of the continent where people have for quite a long time assumed that it’s relatively stable,” says glaciologist Stewart Jamieson from Durham University.
“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.”
The worrying aspect about supraglacial lakes is that they are short-lasting: they eventually refreeze and disappear or drain into the floating ice or merge with rivers on the surface, thereby draining the ice underneath. The first option is harmless enough. However, the latter two are thought to have the potential of weakening ice sheets, and even ice shelves, which might then be destroyed. The cold fresh lake water penetrating salty water will trigger flow patterns under the surface that can lead to more ice being lost.
As mentioned before, these lakes are the result of climate change. Therefore, if temperatures rise again, the negative effects will also be amplified.
“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.
Does this mean that the end of the ice sheet of East Antarctica is near?
“The size of the lakes … are probably not big enough to do much at present, but if climate warming continues in the future, we can only expect the size and number of these lakes to increase. So that’s what we’re looking at,” Jamieson says.