Greenland lakes are draining away in hours, thanks to an extensive network of crevasses hidden in the ice below. (Credit: Timo Lieber)
Visit Greenland on the right summer day, and you could be a 12-billion-gallon lake will disappear before your eyes.
Glaciologists saw this happen for the first time in 2006, when a 2.2 square miles (5.6 square kilometers), more of the melted ice drained to nothing in less than 2 hours. Researchers now see these events as a regular part of Greenland is increasingly the hot summer of the routine; every year, thousands of temporary lakes pop-up on Greenland is the surface of the surrounding ice melts, sit for a few weeks or months, and then suddenly drain away through cracks in the ice sheet underneath. [Images of Melt: Earth’s Vanishing Ice]
On a recent expedition, but the researchers saw an alarming new pattern behind Greenland’s mysterious disappearing lakes: They begin to drain further and further into the interior. According to a new article published today (14 March) in the journal Nature Communications, that is because the summer lakes in Greenland to drain in a “cascading” chain-reaction enabled by a large, interconnected web of cracks under the ice when the temperatures are climbing, the web is becoming wider.
“Lakes that drain in a field, the produce of fractures that lead to more lakes to drain anywhere else,” co-author Marion Bougamont, a glaciologist at the University of Cambridge Scott Polar Research Institute, said in a statement. “Then it will be if you look at the paths of the water under the ice.”
In the new paper, Bougamont and her colleagues used 3D-ice-flow models, and satellite images of the Greenland ice sheet to study this reaction. The authors found that warming of the earth is one more to drain into the underlying ice sheet, the ice flow below, more can speed up dramatically — up to 400 percent faster than in the winter months.
If the water is draining peaks away from the original more, it can destabilize other nearby ice beds. Fresh tears form, new lakes, drain, and the response is strengthened day by day. In one incident, the researchers observed 124 lakes drain in just five days. Even lakes that formed hundreds of kilometres inland, which were previously seen as too far removed from the ice bed to drain into the proved vulnerable to the chain-drain-reaction as new cracks in the ice formed.
This all amounts to billions of gallons of melted ice plunging below Greenland’s surface every few days. A portion of this water remains trapped in the ice sheet; much of the landfill into the surrounding ocean.
“This ice sheet, which covers 1.7 million square kilometres [650,000 square kilometers], was relatively stable 25 years ago, but now loses one billion tons [900 million tons] of ice cream every day,” lead author Poul Christoffersen, also of Cambridge, Scott Polar Research Institute, said in the statement. “This ensures that one millimeter of global sea level rise per year, a rate that is much faster than what was predicted just a few years ago.”
According to a 2017 report, ice loss in Greenland was responsible for about 25 percent of the global rise of the sea level in 2014 — up from just 5 percent in 1993.
If Greenland melts completely, this could lead to a global sea level rise of about 20 feet (6 meters). According to the researchers, from Cambridge, of a total loss of the Greenland ice is “very unlikely in this century” — but even small increases in sea level can have serious consequences all over the world, the authors stated. According to a recent report from the National Oceanic and Atmospheric Administration (NOAA), as the sea level rises half a meter (1.6 feet) by 2100, many American coastal cities will experience overflow, “every other day” or more.
Originally published on Live Science.