Greenland's ice sheets could be more sensitive to warming waters than researchers previously believed; they could also be putting the world in more danger.
The bedrock canyons are located below sea level, so subtropical Atlantic waters that hit the front of the glacier will most likely cause more erosion than expected, a University of California - Irvine news release.
These warm marine currents have already migrated North, but past models predicted that once higher land was reached the melting would stop.
"That turns out to be incorrect. The glaciers of Greenland are likely to retreat faster and farther inland than anticipated - and for much longer - according to this very different topography we've discovered beneath the ice," lead author Mathieu Morlighem, a UCI associate project scientist said in the news release. "This has major implications, because the glacier melt will contribute much more to rising seas around the globe."
Greenland's subsurface is extremely difficult to survey because it is so rugged. Pockets of water can also interfere with radar mapping, making some areas almost impossible to see.
In order to reveal these hidden regions the researchers created a "mass conservation algorithm" that took previous ice-thickness measurements and compared them with information on the "velocity and direction of its movement and estimates of snowfall and surface melt," the news release reported.
The team found that what appeared to be shallow glaciers were actually "long, deep fingers" that stretched for up to 65 miles.
"We anticipate that these results will have a profound and transforming impact on computer models of ice sheet evolution in Greenland in a warming climate," the researchers said in the news release.
"Operation IceBridge vastly improved our knowledge of bed topography beneath the Greenland Ice Sheet," co-author Eric Rignot of UC Irvine and NASA's Jet Propulsion Laboratory said in the news release. "This new study takes a quantum leap at filling the remaining, critical data gaps on the map."