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Antarctic Glaciers Are Unstable, Can Slide Off Into Sea

11 July 2019

Antarctic ice melt and climate change will contribute to rising sea levels around the globe over the next 150 years.

Five Antarctic glaciers have doubled their rate of ice loss over the last six years, according to the study, with at least one (the Thwaites Glacier) being in danger of collapse.

Earlier this year, NASA scientists found a massive hole two-thirds the size of Manhattan under the Thwaites Glacier.

And scientists say annual sea level rise has roughly doubled since 1990 - and could worsen if the Thwaites Glacier were to melt.

"After reaching the tipping point, Thwaite's Glacier might lose all of its ice in 150 years", Hélène Seroussi, an author of the research and a NASA scientist, mentioned in a press release. This could translate to a sea level rise of about half a meter or 1.64 feet.

Study leader Dr Alex Robel, Assistant Professor in Georgia Institute of Technology's School of Earth and Atmospheric Sciences, said: "If you trigger this instability, you don't need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that's the worry", said Robel. Glacier instability/collapse first starts here.

Thwaites fglacoer measures approximately 70,000 miles (about the size of the U.S. state of Florida) and scientists have warned it is reaching "tipping point", meaning it will be impossible to reverse the process of the glacier melting and raising sea levels.

As the ice melts and crumbles into the oceans, the amount of present water pushes up on coastal areas, threatening floods around the globe.

Thwaites Glacier could lose all its ice in the next 200 to 600 years, and that would result in a global sea-level increase of about 1.64 feet, says a new study, although another study approximates the rise of the levels to about 2 feet.

That cavity was large enough to have held 14 billion tons of ice. However, the researchers warn that if ocean temperatures continue to rise, the instability in the glacier could occur much faster than many expect.

The world's 99% of freshwater consists of the co-joint sheets of ice from Greenland and Antarctica, and most of this water is frozen in masses of ice that can be as thick as 10,000 feet. The point where the overhanging glacier, sea and bedrock meet is called the "grounding line". Ice loss is spreading from the coast into the continent's interior, with a reduction of more than 100 metres in thickness at some sites.

"As more heat and water get under the glacier, it melts faster".

The situation is so bad that it could happen even under present-day ice-melting rates.

But he added: "Climate variations will still be important after that tipping point because they will determine how fast the ice will move".

The scientists reported within the journal Proceedings of the Nationwide Academy of Sciences that the glacier poses the most significant risk to future sea-stage rise and is likely marching in the direction of an irreversible melting level.

As the researchers see it now, Thwaites prevents its neighbors from falling into the ocean.

Antarctic Glaciers Are Unstable, Can Slide Off Into Sea