A gigantic cavity, 40 square miles high and 300 meters high, grows at the bottom of the Glacier glacier in western Antarctica and confirms that this mass of ice falls apart.
It also highlights the need for detailed observations on the lower Antarctic Antarctic munitions to calculate how quickly global sea levels will increase in response to climate change.
The researchers hoped to find some gaps between the ice and the rock at the base of Thwaites, where ocean water can flow and melt the glacier from below.
However, the size and explosive growth rate of the new hole surprised them. It is large enough to hold 14 billion tons of ice, and most of that ice melts in the last three years.
"For years we have doubts that the Thwaites are not well connected to the core rock," says Eric Rigot of the University of California, Irvine, and the laboratory for the NASA Motors Laboratory (JPL). Rignot is co-author of the new study, which
is published in "Science Advances". "Thanks to the new generation of satellites, we can finally see the details," he said.
The cavity was discovered by a radar for ice penetration in NASA, IceBridge, an air campaign that began in 2010 and explores the links between polar regions and the global climate.
The researchers also used data from a radar constellation for synthetic aperture from Italian and German spacecraft. These very high resolution data can be processed by a technique called radar interferometry to reveal how the surface of the earth below is moved between the images.
"[El tamaño de] "The holiday under the glacier plays an important role in melting," lead author of the study, Peter Milillo of the JPL, said. "As more heat and water penetrate the glacier, it melts faster," he said.
Numerical ice models use a fixed form to represent a cavity under the ice, rather than allowing the cavity to change and spread. The new discovery implies that this limitation probably makes these models underestimating how fast Thwaites are losing ice.
Thwaites Glacier, the size of the state of Florida, the United States, is currently responsible for about 4 percent of sea-level rise around the globe. There is enough ice to raise the world's ocean slightly over 2 centimeters and keeps the adjacent glaciers, which will raise the sea level by 2.4 centimeters if the entire ice is lost.
Thwaites are one of the hardest places to reach the Earth, but will be better known than ever. The National Science Foundation of the United States and the National Council for Environmental Research of the United Kingdom set up a five-year outreach project to respond to the most critical issues related to their processes and features. The international Thwaites Glacier Collaboration will launch its field experiments in the southern hemisphere summer 2019-20.
The huge gap lies beneath the main trunk of the glacier on its west side, the furthest side of the West Antarctic Peninsula. In this region, when the tide rises and falls, the surface linking line reaches and progresses through an area of about 3 to 5 kilometers.
The glacier is separated from the rock-basin at a constant rate of about 0.6 to 0.8 kilometers per year since 1992. Despite this stable rate of withdrawal in the fixed line, the fusion rate On this side of the glacier is extremely high.