Antarctic Glaciers Are Unstable, Can Slide Off Into Sea

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According to USA researchers, the melting of ice spread from the suburbs into the inner part of the continent, and in some places the thickness of glaciers has decreased by 100 metres.

Now, authors of a new study report that over the last six years, the rate at which five Antarctic glaciers slough off ice has doubled. However, 500 simulations of different scenarios pointed to it losing stability.

Instability in Antarctic glaciers is found around the grounding line, where the bedrock underneath the glacier meets the ocean.

The Thwaites Glacier is a large mass of ice born from snow that's been compressed over time. "It will keep going by itself, and that's the worry", lead researcher Alex Robel, an assistant professor in Georgia Tech's School of Earth and Atmospheric Sciences, said in a news release.

Antarctica is ringed by a skirt of ice sheets and floating ice shelves that create a physical barrier between the ocean and the landlocked ice on the continent. Most of that ice has melted over the past three years. That makes the Thwaite's Glacier a melting time bomb.

Depending on how fast global warming continues and the nature of the glacier's instability, extensive ice loss would start in 600 years according to modeling simulations in the research. However, he added, "climate variations will still be important after that tipping point because they will determine how fast the ice will move".

The ice giant is heading towards a doomsday "instability" which once crossed means it could all float out into the sea and melt within 150 years, the NASA-funded study found.

In other words, even if climate change was magically reversed, it wouldn't necessarily stop the unsafe and rapid rise in sea levels that could be triggered by unstable ice sheets.

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Mr Seroussi added: "The process becomes self-perpetuating".

Currently, sea levels are 20 cm (almost 8 inches) above pre-industrial levels. But their contribution to sea level rise pales in comparison to what we may see now that the Antarctic ice sheet faces a tipping point - a point of no return. They need more data to drive accurate conclusions.

There are plenty of ominous indicators of the consequences of climate change, but few are more worrying to scientists than the ice sheets of Antarctica at our planet's southern pole.

It's not yet clear whether Thwaites has reached the tipping point or not, but its outer edge is sinking into the ocean faster than previously recorded. Why is Antarctic ice the big driver of sea level rise? However, the current study shows that our current forecasts aren't very reliable.

According to Insider.com, some sections of the Thwaites Glacier "are retreating by up to 2,625 feet per year, contributing to 4% of sea-level rise worldwide". Ice flow in such conditions will increase gradually, not wildly, but the instability produced the opposite effect in the simulations.

But Dr Robel added: "The system didn't damp out the fluctuations, it actually amplified them".

"[Almost total ice loss in Thwaites] could happen in the next 200 to 600 years".

"It depends on the bedrock topography under the ice, and we don't know it in great detail yet", Seroussi said.

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