Researchers were busy building the highest resolution map of the Greenland Ice Sheet (read more about that here) when they noticed something strange. Two lakes of melt water which had pooled beneath Greenland’s Ice Sheet were rapidly draining.
Imagine a lake holding 6.7 billions of gallons of water becoming an empty, mile-wide crater in just a few weeks. That’s what researchers found in one of the lakes. The other lake has filled and been drained twice in the last two years.
Two studies were published – highlighting the two lakes separately.
The study covering the lake that left behind the mile-wide crater was led by Ian Howat, an associate professor of earth sciences at Ohio State. Howat believes the incredibly quick draining of the lake is just more evidence the ice sheet’s drainage system is being overflowed.
“The fact that our lake appears to have been stable for at least several decades, and then drained in a matter of weeks—or less—after a few very hot summers, may signal a fundamental change happening in the ice sheet,” Howat said.
Howat described the drainage as “catastrophic.”
The other lake measures two miles wide and has filled and drained twice in two years. That study was published in Nature and was led by Michael Willis of Cornell University. Michael Bevis, professor of earth sciences at Ohio State, was co-author on the paper.
The problem with regular filling and draining of lakes beneath Greenland’s Ice Sheet is the latent heat that gets carried along with it. Here’s Bevis explaining why this is a problem.
“If enough water is pouring down into the Greenland Ice Sheet for us to see the same sub-glacial lake empty and re-fill itself over and over, then there must be so much latent heat being released under the ice that we’d have to expect it to change the large-scale behavior of the ice sheet,” he said.
Bevis warns “with melting like that, even the deep interior of the ice sheet is going to change.”
Image credit: Wikipedia/Hannes Grobe