Tecnologia

'Dangerous' Antarctic glacier has massive hole, scientists warn

Fevereiro 04, 2019 23:51·
NASA makes'disturbing find under Antarctic glacier

NASA makes'disturbing find under Antarctic glacier

JPL said the glacier, about the size of Florida, holds enough ice to raise ocean levels another 60 centimetres if it completely melts.

The cavity was revealed by ice-penetrating radar in NASA's Operation IceBridge, an airborne campaign beginning in 2010 that studies connections between the polar regions and the global climate.

The Thwaites Glacier is roughly the size of Florida and is now responsible for 4 percent of the global sea level rise, according to the study. This empty space has the negative effect of speeding up the rate at which the glacier melts and, in turn, how quickly sea levels rise.

The hollowed-out section is two-thirds the size of Manhattan and 1,000 feet tall - big enough to have contained 14 billion tons of ice, according to a new study in the journal Science Advances.

Numerical models of ice sheets use a fixed shape to represent a cavity under the ice, rather than allowing the cavity to change and grow. Recently, some holes have been discovered between ice and bedrock at Thwaites' bottom.

"The size and explosive growth rate of the newfound hole, however, surprised them", they said. Thwaites has been described as one of the world's most unsafe glaciers because its demise could lead to rapid changes in global sea levels. The size of the cavity was published in a study which was realised by NASA's Jet Propulsion Laboratory.

"On the eastern side of the glacier, the grounding-line retreat proceeds through small channels, maybe a kilometre wide, like fingers reaching beneath the glacier to melt it from below", he said.

One aspect of a glacier that scientists track closely is a grounding line, which is where a tidewater glacier - or one that flows all the way down to the ocean - begins to float. "Thanks to a new generation of satellites, we can finally see the detail", he said.

West Antarctica's Thwaites Glacier has covered 70,270 square miles, nearly the approximate size of Florida. Last year, the National Science Foundation and Britain's Natural Environment Research Council launched a joint programme called the International Thwaites Glacier Collaboration to study the unstable glacier and its role in sea levels. The giant cavity under Thwaites Glacier is located on its western side, which is where the melting rate was found to be the fastest. As sea levels rise, coastal communities and low-level land areas become more susceptible to flooding and will force millions of people to relocate. Co-authors were from the University of California, Irvine; the German Aerospace Center in Munich, Germany; and the University Grenoble Alpes in Grenoble, France.

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