Scientists have discovered the deepest point on Earth, buried under the Antarctic ice sheet.
Thanks to new technology dubbed the BedMachine, researchers at the University of California Irvine are now able to “see” what’s underneath the thick ice covering Antarctica. The glaciologists mapped the region using ice-thickness data drawn from 19 institutions since 1967, combined with ice shelf measurements gleaned from NASA’s Operation IceBridge campaigns, as well as seismic information.
The combination of data generated the most detailed images of the region to date, which helps scientists predict the effects that climate change is likely to have. The findings were published Thursday in the journal Nature Geoscience and unveiled at the fall meeting of the American Geophysical Union in San Francisco, happening this week.
“Using BedMachine to zoom into particular sectors of Antarctica, you find essential details such as bumps and hollows beneath the ice that may accelerate, slow down or even temporarily stop the retreat of glaciers,” lead author Mathieu Morlighem, UCI associate professor of Earth system science, said in a statement.
Some of the findings were unexpected.
“There were lots of surprises around the continent, especially in regions that had not been previously mapped in great detail with radar,” Morlighem said. “Ultimately, BedMachine Antarctica presents a mixed picture: Ice streams in some areas are relatively well-protected by their underlying ground features, while others on retrograde beds are shown to be more at risk from potential marine ice sheet instability.”
Previous measurement methods gave a generally accurate picture, but with some gaps. The BedMachine enabled researchers to use physics calculations to fill in those gaps by calculating conservation of mass.
In other words, as BBC News explained, they could determine, say, the volume of ice moving into a narrow valley and measure its speed to gain insight into the terrain below. This method revealed the Denman Glacier, about 12.5 miles wide, descends 3,500 meters below sea level — the deepest canyon on land, BBC News noted, at 11,500 feet.
“Older maps suggested a shallower canyon, but that wasn’t possible; something was missing,” Morlighem said in the researchers’ statement. “With conservation of mass, by combining existing radar survey and ice motion data, we know how much ice flows through the canyon – which, by our calculations, reaches 3,500 meters below sea level, the deepest point on land. Since it’s relatively narrow, it has to be deep to allow that much ice mass to reach the coast.”
The lowest point on Earth that’s on exposed land is at the Dead Sea, which is 1,355 feet below sea level, BBC News said, and underneath the sea, in the Mariana Trench, is 36,089 feet, below sea level.
All this data has implications for predicting the possible effects of melting ice on the region, Morlighem told BBC News. For instance, it could dispel fears of a collapse of East Antarctica’s entire ice sheet from deterioration of the Ross Sea Ice Shelf, since the underlying terrain would not permit it.
“If something happened to the Ross Sea Ice Shelf — and right now it’s fine, but if something happened — it will most likely not trigger the collapse of East Antarctica through these ‘gates,’ ” he told BBC News. “If East Antarctica is threatened, it’s not from the Ross Sea.”