January 31, 2019 – 16:47
The Thwaites have a similar size of the state of Florida and its mass contains 14,000 million tons of ice. Its decay can increase the ocean level by two centimeters.
Due to its responsibility for rising sea levels, it is considered the most dangerous glacier in the world. And now, a new investigation raises the warning. The giant cavity, 40 square miles high and 300 meters, rising at the bottom of Thwaites Glacier in western Antarctica, confirms that this mass of ice falls apart.
Findings from a new NASA study highlight the need for detailed observations on the lower Antarctic munitions to calculate how quickly global sea levels will rise in response to climate change.
The researchers hoped to find some gaps between the ice and the rock at the bottom of Thwaites where ocean water could 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.
"The size of the glacier below the glacier plays an important role in fusion," says lead author of the study, Peter Milillo, a NASA laboratory for the dip laboratory (JPL). "As more heat and water they penetrate the glacier, it melts faster."
"For years we have doubts that the Thwaites are not well connected to the core rock," added Eric Rigot of the University of California and 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.
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 begin its field experiments in the next summer of the southern hemisphere.
The size of the state of Florida, Thwaites Glacier is currently responsible for about 4% of the world's sea level level. There is enough ice to raise the world's ocean slightly over 2 centimeters and holds the adjacent glaciers that will raise the sea level by 2.4 centimeters if the entire ice is lost.
The huge emptiness is below the main trunk of the glacier on its west side, farthest from 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 was separated from the ridge in the substrate at a constant rate of about 0.6 to 0.8 kilometers per year since 1992. Despite this stable rate of land withdrawal, the fusion rate at This side of the glacier is extremely high.
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 is likely to cause these models to underestimate how fast Thwaites are losing ice.