Published: Fri, February 01, 2019
Sci-tech | By April Francis

‘Disturbing Discovery’: Scientists Find Giant Hole in Antarctica

‘Disturbing Discovery’: Scientists Find Giant Hole in Antarctica

A massive cavity that is two-thirds the size of Manhattan and almost the height of the Chrysler Building is growing at the bottom of one of the world's most unsafe glaciers - a discovery that NASA scientists called "disturbing".

"[The size of] a cavity under a glacier plays an important role in melting", Milillo says.

Scientists thought there might be some gaps between Thwaites Glacier and the bedrock below it, where ocean water could flow in and melt the icy glacier above it.

However, the researchers say that the size and growth rate of the hole surprised them.

For starters, the void is large enough to have once held 15 billion tons (13.6 billion metric tons) of ice, but much of that ice has melted during the past three years, according to NASA. That cavern is likely filled with air much warmer than the surrounding ice, triggering faster melting of the glacier than would happen otherwise.

A large cavity has formed under what has been described as one of the world's most risky glaciers, and could contribute to a significant bump in global sea levels, said Nasa scientists.

Instead, the team used airborne and satellite ice-penetrating radars to reveal the cavity.

"We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it", says glaciologist Eric Rignot from the University of California, Irvine, and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

'Thanks to a new generation of satellites, we can finally see the detail'.

The Thwaites Glacier, which is about the size of Florida, has been responsible for about 4% of the rise in sea levels so far, still holds enough ice to raise the world ocean a little over 2 feet upon melting.

And worse, its neighbouring glaciers would raise sea levels an additional eight feet if all the ice was lost.

The melting in Thwaites Glacier, approximately the size of Florida in the USA, contributes four percent of global sea level rise each year.

The International Thwaites Glacier Collaboration will begin its field experiments in the Southern Hemisphere summer of 2019-20.

"We are discovering different mechanisms of retreat, ' Mr Milillo said".

The newly discovered cavity sits on the western side of the glacier, where the melt rate was found to be fastest. In that region, the rate of grounding-line retreat doubled from about 0.4 miles (0.6 kilometers) a year from 1992 to 2011 to 0.8 miles (1.2 kilometers) a year from 2011 to 2017.

The complex pattern the new readings reveal - which don't fit with current ice sheet or ocean models - suggest scientists have more to learn about how water and ice interact with one another in the frigid but warming Antarctic environment.

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