WeatherFanatics: Why beautiful blue lakes forming on East Antarctica have scientists worried

Friday, September 9, 2016

Why beautiful blue lakes forming on East Antarctica have scientists worried

By Amanda Schmidt, AccuWeather Staff Writer

September 9,2016; 7:29PM,EDT

Beautiful, blue lakes are beginning to form atop of East Antarctica ice sheets, but despite their breathtaking aura, these lakes are sparking concerns among scientists.
Supraglacial lakes form during the warmer summer months when temperatures tend to rise above freezing. The higher air temperature at the surface causes the snow over the glacier to melt and form these ponds.
However, these dazzling meltwater ponds may pose serious threats for glaciers.

The two images are a "before" and "after" showing lake drainage in the same area. These are compiled from ASTER data acquired on the 14th and 26th January 2005 (Data supplied by the Land Processes Distributed Active Archive Center (LP DAAC) managed by the NASA Earth Science Data and Information System (ESDIS) project.)
The formation of these lakes may be linked to climate change and rising global temperatures.
This is not the first time that these lake formations have been observed. These meltwater ponds are also a distinct feature of the Greenland ice sheet, the fastest melting glacier on Earth.
The draining of supraglacial lakes is considered to be one of the reasons that Greenland is melting at an accelerated rate.
On the opposite side of the globe lies the largest and coldest ice mass on Earth, Antarctica. East Antarctica is considered to be far more stable and less dynamic than Greenland and other parts of Antarctica, therefore there has been less research surrounding lake formations and ice sheet instabilities.
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However, a recent study exposed that this large glacier started to form characteristics reminiscent of the Greenland ice sheet. The study used meteorological records and satellite images in the summer between 2000 and 2013 to discover that nearly 8,000 supraglacial lakes have formed atop the Langhovde Glacier in East Antarctica.
"[Lake drainage] raises concern because it may mean that the ice sheet will become unstable and may lead the ice sheet to surge or slide a bit more easily," Professor of Geography and Climatology at Penn State University Dr. Andrew Carleton told AccuWeather.
Carleton recently co-advised on a separate study that monitored supraglacial lakes on Greenland. These lakes could potentially lead the ice sheet to surge. Surging of the ice sheet could lead sea level to increase much more dramatically, Carleton said.
There has been little evidence of these lake drainage events in East Antarctica; however, as these lakes continue to evolve, the likelihood of lake drainage events will increase.
A recent study, released in the Geophysical Research Letters, is the first long-term record of meltwater ponds that have started to spread across East Antarctica.
The study was led by Emily Langley of Durham University, who worked along with Stewart Jamieson and Chris Stokes from her university and Amber Leeson of Lancaster University.
Their observations of the Langhovde Glacier confirmed there were many lakes forming on the ice sheet during the summer months. The study found a correlation between surface air temperature and the extent of the lakes.

Researchers have been studying the lakes on the Langhovde Glacier in East Antarctica. (Satellite image courtesy of DigitalGlobe, Inc.)
"It's not hitting the glacier really hard at the moment, this process, but of course, as things warm up, we'd expect it to start doing more damage, like we see in Greenland," Jamieson told The Washington Post.
Over the summers of 2012 and 2013, temperatures climbed above freezing on 37 days. During that time period, there was a positive correlation to more lakes with greater area and greater depth, Langley said.
Although this correlation is unsurprising, it is important to continue to monitor, Langley said. It is also crucial to monitor where the water goes if it does not refreeze.
"The majority of lakes that we saw on Langhovde Glacier did refreeze at the end of the summer, but we did observe a few that disappeared during peak summer temperatures, which would imply that the water drained somewhere," Langley said.
In Greenland, lake drainage is a key concern as the meltwater is able to drain into the bedrock and act almost as a lubricating fluid. This can increase the velocity and speed of the ice and can allow more ice to drop into the sea, thus increasing sea level.
On the Langhovde Glacier, this mechanism has not been observed. Lake drainage events have taken place on the floating ice, or ice sheets that extend beyond the bedrock and begin to float on the sea.
"This is a really important area to monitor because I would look at the studies that have been done on the Antarctic Peninsula and West Antarctica where there has been research to suggest that lakes that drain on the floating ice shelf may contribute to ice shelf disintegration," Langley said.
Drainage events have the possibility to weaken the ice shelf, which could result in a less stable glacier. This would, in effect, lead to an increased rate of global sea level rise.
Because the study was done over a 13-year period, the authors were unable to make any long term predictions on lake behavior.
"The fact that we saw some lake drainage makes this an area to monitor in the future to see if they become more prevalent and what their impact is on the stability of the ice shelf," Langley said.