NASA scientists have discovered a gigantic cavity, almost 300 meters high, that grows at the bottom of the Thwaites glacier in West Antarctica, indicating a rapid decomposition of the ice sheet and an acceleration in global levels of the ice. sea due to climate change.
The findings, published in the journal Science Advances, highlight the need for detailed observations of the bottom of the Antarctic glaciers to calculate how fast sea levels will rise in response to warming.
The researchers hoped to find some breaches between the ice and the bedrock at the bottom of Thwaites where ocean water could flow and melt the glacier from below, NASA said in a statement.
“Thanks to a new generation of satellites, we can finally see the details,” said Rignot, who is also associated with NASA’s Jet Propulsion Laboratory (JPL).
The cavity was revealed by a radar that penetrates the ice in NASA’s Operation IceBridge, an airborne campaign that began in 2010 and studies connections between the polar regions and global climate.
The researchers also used data from a constellation of Italian and German synthetic aperture radars.
This very high resolution data can be processed by a technique called radar interferometry to reveal how the surface of the ground below has moved between the images.
“(The size of) a cavity beneath a glacier plays an important role in the merger. As more heat and water penetrate the glacier, it melts faster, “said Pietro Milillo of JPL.
Thwaites glaciers are currently responsible for approximately four percent of global sea level rise, the researchers said.
He argues that there is enough ice to lift the global ocean a little over 65 centimeters and supports neighboring glaciers that would raise sea levels by an additional 2.4 meters if all the ice were lost, they said.
“We are discovering different withdrawal mechanisms,” said Millilo.
According to NASA, different processes in several parts of the 160-kilometer-long front of the glacier are causing the return rates of the ground connection and ice loss lines to be out of sync.
The huge cavity lies beneath the main trunk of the glacier on its western side, the farthest side of the Western Antarctic Peninsula.
In this region, as the tide rises and falls, the ground connection line retreats and advances through an area of about three to five kilometers.
The glacier has been peeling off a ridge in the bedrock at a constant rate of approximately 0.6 to 0.8 kilometers per year since 1992.