NASA warns that a dangerous glacier in Antarctica is on the verge of collapse

A gigantic 40-square-meter, 300-meter-high cavity grows at the bottom of the Thwaites Glacier in western Antarctica, and confirms that this mbad of ice is disintegrating.

This is confirmed by a new study conducted by the

The NASA,

It also highlights the need to look in detail at the lower Antarctic glaciers to calculate how quickly sea level will rise in response to climate change.

The researchers hoped to find empty spaces between the ice and the rock at the base of Thwaites, where the water from the ocean can flow and melt the glacier from below.

The size and explosive growth rate of the new hole, however, surprised them. It's big enough to hold 14 billion tonnes of ice, and most of that ice has melted in the last three years.

"We have thought for years that Thwaites was not well attached to the underlying rock," said Eric Rignot of the University of California at Irvine and NASA's Jet Propulsion Laboratory (JPL). Rignot is co-author of the new study, which
"Thanks to a new generation of satellites, we can finally see the details," he said.

The cavity was revealed by an ice penetration radar in NASA's IceBridge operation, an air campaign launched in 2010 that studies connections between the polar regions and the global climate.

The researchers also used data from a constellation of synthetic aperture radars from Italian and German spacecraft. These very high resolution data can be processed by a technique called radar interferometry to reveal the evolution of the ground surface located between the images.

"[El tamaño de] A cavity under a glacier plays an important role in melting, "said lead author of the study, Pietro Milillo, of JPL. The more heat and water enter the glacier, the hotter the melt, "he said.

Numerical models of ice caps use a fixed shape to represent a cavity under the ice, instead of allowing the cavity to change and develop. The new discovery implies that this limitation probably makes these models underestimate the speed with which Thwaites loses ice.

Thwaites Glacier, the size of the state of Florida, is currently responsible for about 4% of the rise in sea level around the world. It has enough ice to lift the global ocean a little over 2 centimeters and holds the nearby glaciers, which would raise the sea level by 2.4 centimeters if all the ice was lost.

Thwaites is one of the most difficult places to reach on Earth, but it is about to be better known than ever. The National Science Foundation of the United States and the National Environmental Research Council of the United Kingdom are preparing a five-year field project to answer the most critical questions about their processes and characteristics. The Thwaites Glacier International Collaboration will begin its field experiments in the southern hemisphere in the summer of 2019-20.

The huge cavity lies beneath the main glacier trunk on the west side, the farthest side of the western Antarctic Peninsula. In this region, when the tide goes up and down, the ground connection line moves back and forth over an area of ​​about 3 to 5 kilometers.

The glacier has been detached from a ridge in the bedrock at a constant rate of about 0.6 to 0.8 km per year since 1992. Despite this rate of steady decline in the land line, the melting rate on this side from the glacier, it is extremely high.

DPA Agency