31 January 2019 – 16:47
Thwaites are similar in size to the state of Florida, and its weight includes 14,000 million tons of ice. Its decay could raise the ocean level by two centimeters.
Because of its responsibility for rising sea levels, it is considered to be the most dangerous glacier in the world. And now a new investigation raises warnings. An enormous cavity of 40 square kilometers and 300 meters, growing at the bottom of the Thwaites glacier in the western Antarctic, confirms that this ice mass is falling apart.
The findings of a new NASA study highlight the need for detailed observation of the lower part of the Antarctic glaciers to calculate how quickly global sea levels rise in response to climate change.
Scientists hoped to find some gaps between ice and rocks in the lower Thwaites, where water from the ocean could flow and melt the glacier from behind. However, the size and speed of the new hole exploded. It is large enough to hold 14 billion tons of ice, and most of this ice melt in the last three years.
"The size of the cavity under the glacier plays an important role in the merger," said lead author Pietro Milillo of NASA's Jet Propulsion Laboratory (JPL). "Because more heat and water penetrate into the glacier, it rotates faster."
"For years, we have suspected that Thwaites was not well connected with the undercoat," said Eric Rignot of the University of California and JPL. Rignot co-authored a new study published in the journal Science Advances. "Thanks to the new generation of satellites, we can finally see the details," he said.
The cavity was unveiled with radar for ice penetration in Operation NASA Operation IceBridge, an air campaign that began in 2010 and studies connections between the polar regions and the global climate. Researchers also used data from constellations of synthetic radar from the Italian and German spacecrafts. These high-resolution data can be processed by a technique called radar interferometry, which reveals how the surface of the earth moves below.
Thwaites is one of the most difficult places to reach Earth, but will 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 properties. International Thwaites Glacier Collaboration will begin its field experiments in the summer of the Southern Hemisphere.
The size of the state of Florida, the Thwaites Glacier, is currently responsible for about 4% of sea levels worldwide. It has enough ice to raise the world's ocean by just over two centimeters and maintains adjacent glaciers that would raise the sea level by 2.4 centimeters if the ice were lost.
The huge cavity is below the main glacier trunk on its western side, farthest from the western Antarctic peninsula. In this area, when the tide rises and falls, the earth clutch retracts and progresses over an area of approximately 3 to 5 kilometers. Since 1992, the glacier has been graduated from the ridge in the subsoil since the end of 1992 at a constant speed of 0.6 to 0.8 kilometers per year. Despite this stable landing rate, the fusion speed is extremely high.
Numerous models of ice tables use a solid form that represents the cavity under the ice instead of allowing the cavity to change and grow. The new discovery assumes that this restriction is likely to cause these models to underestimate how quickly Thwaites loses ice.