Something strange is happening to one of the coldest places on Earth. Dazzling blue lakes are blooming like summer wildflowers atop the East Antarctic ice sheet's Langhovde Glacier. And that's got scientists worried — because they have seen these lakes before. Lakes on Langhovde Glacier. Satellite image courtesy of DigitalGlobe, Inc.
"Supraglacial lakes" — meltwater ponds that form as warm summer air heats the surface of an ice sheet — have been spreading across Greenland for years. They're both a sign of global warming and a cause of ice sheet collapse: As meltwater from the lakes drains into the underlying ice, it can lubricate the ice sheet's foundation, causing it to weaken. This feedback is thought to be one of the reasons Greenland is now melting at an accelerating rate. (Earth's northernmost ice sheet shed roughly a trillion tonnes between 2011 and 2014.)
Now, the lakes have jumped to the other end of the world, peppering an ice sheet that's enjoyed relative stability compared with its overheated neighbour to the north. A new study in Geophysical Research Letters drew on satellite and meteorological data to construct the first long-term record of meltwater ponds along the coast of East Antarctica. According to the authors' analysis, nearly 8000 dazzling blue lakes appeared on the Langhovde Glacier in the summertime between 2000 and 2013.
As in Greenland, many of these ephemeral lakes appear to be draining their contents into the underlying ice. It's the first time this behaviour has been observed in East Antarctica, a place that study co-author Stewart Jamieson, describes as "the part of the continent where people have for quite a long time assumed that it's relatively stable, there's not a huge amount of change, it's very, very cold".
The presence of the lakes is, unsurprisingly, tied directly to temperature, with the greatest number of lakes forming in the unusually warm summer of 2012-2013.
It's a bit early to say whether East Antarctica's fresh summer look is going to mean trouble in the long-term. "We do not think that the lakes on Langhovde Glacier are at present affecting the glacier, but it will be important to monitor these in the future to see how they evolve with surface air temperature changes," lead study author Emily Langley told Gizmodo in an email.
Indeed, the prospect of more lakes and larger lakes is worrisome, because Antarctica contains much more ice than Greenland, enough to raise global sea levels dozens of metres if it all decided to melt. Recent studies suggest that parts of this icy fortress — particularly the West Antarctic ice sheet — could be far more sensitive to a few degrees of warming than we had hoped.
On a brighter note, maybe that absurd Antarctic hotel will soon become a lakefront getaway. Imagine: For a mere $US72,000 ($93,605), you'll be able to hang out with emperor penguins and watch the world end in real time. How fun!