Subglacial lakes are among the least explored and important natural features of the earth. We also underestimated their distribution and impact by far.
Meanwhile, more than 400 of these lakes have been found under the Antarctic continent. Back in the 1950s, scientists thought that this ice sheet contained no liquid water at all.
Now a similar story is taking place in the northern hemisphere. New research has increased the number of known lakes lurking beneath the Greenland Ice Sheet to a total of 60, from 14 times that of only four recognized waters.
"With this study, we were able to begin to build a picture of where lakes form under the Greenland ice sheet," says senior author and hydrologist Jade Bowling of Lancaster University.
"This is important to determine their influence on the further subglacial hydrological system and the dynamics of the ice flow. Improvement of our understanding of the thermal ground state of the ice cover."
Greenland's ice sheet is several kilometers thick and it is still unclear What exactly is going on under their frozen outside. As the world continues to warm, the frozen colossus loses an estimated 244 billion tons of ice each year. If the whole thing melts, the sea level can rise by up to 7 meters.
] For future climate models, it is therefore crucial to understand what glacial meltwater is doing on its way from the surface to the bed, and subglacial lakes are an important temporary stop.
If these waters fill and drain in the Antarctic, they can cause superimposed ice to flow faster, and scientists believe the same could happen in Greenland. A study published last year actually predicted that the chain reaction of water discharge in Greenland could accelerate ice flow by as much as 400 percent. Actually finding these subglacial lakes is another story.
The first full survey of subglacial lakes yielded only 56, and the careful analysis required the manual sweeping of 500,000 km of radar echo data as well as changes in surface elevation that show how these lakes swell and increase over time Drain.
Unlike the Antarctic lakes, which can reach up to 1
"In the middle of [Greenland ice sheet] the ice is frozen to a large extent, the Water increases at the edge of ice surface velocity and the likelihood of a hydraulic connection between surface and bed. " Authors.
Slightly less than half of these newly identified lakes are active, which means they both drain and fill due to changes in ice surface elevation. However, the authors of the report fear that these structures may occur more frequently in the future, although they are still rare.
As the climate continues to warm, surface meltwater in Greenland, as in the Antarctic, can form lakes and streams higher in the ice. If these waters drain to the bottom, scientists believe they could "reactivate" these subglacial lakes and reduce the overall stability of the ice cover by reducing gliding and potentially connecting this dormant reservoir with the edge of the ice sheet, "explain the authors.
Edge of the frozen structure of Greenland, where melting tends to be faster, the authors found evidence that this is already happening in two activated lakes.
"These" active "lakes, which fill and drain and the ice up and down lift, seem to be rare, "co-author Stephen Livingstone of the University of Sheffield told the BBC.
" We speculate, however, that the signal of active subglacial lakes near the edge of the ice can actually be lost, because a lot of superficial melt water gets into bed here. "
The edges of the Greenlandic Icy ice cover may hide even more of these dynamic subglacial lakes. As our world heats up rapidly, knowing where and how they exist can make all the difference.
The study was published in Nature Communications .