Collapse of West Antarctic ice sheet has begun

Scientists in two separate studies have reached the same conclusion: A section of the West Antarctic ice sheet has begun to melt rapidly. Once started, it cannot be stopped. Sea levels could rise by up to 4 metres, wiping out coastal cities.

The two studies concluded that the ice melt is being driven by climate change, reports the Guardian. Relatively warmer water at the ocean depths, warmer air temperatures and stronger winds caused by the ozone hole over the Antarctic all play a role. The scientists also warn that the ice melt is occurring at a much faster rate than expected.

According Eric Rignot, a glaciologist at NASA and the University of California, Irvine, six massive glaciers in West Antarctica “have passed the point of no return”. These glaciers contain enough ice boost the global sea level by 1.2 metres.

The University of Washington study focussed on the fast-moving Thwaites glacier. The scientists found that it will likely disappear in a matter of centuries, raising sea levels by nearly 2 feet. The real concern is that the glacier acts as a damn for the rest of the ice sheet, which contains enough ice to cause another 10 to 13 feet (3 to 4 metres) of global sea-level rise.

The NASA-UC Irvine researchers focussed on melting over the last 20 years, while the University of Washington study used computer modelling to look into the future of the western Antarctic ice sheet, explains the Guardian. But both agree that while the sea-level rise is still centuries away, potentially up to 1,000 years, it most likely cannot be stopped. And while more emissions would likely lead to more melting and faster collapse, even drastic action to cut greenhouse gas emissions could not prevent the collapse.

“We feel this is at the point where even if the ocean is not warming up, is not providing additional ocean heat, the system is in a sort of chain reaction that is unstoppable,” Rignot told reporters.

The two studies suggest that sea-level rise will be much higher than envisaged by the IPCC report, which did not factor in melting of the western Antarctic ice sheet, explains the Guardian.

 

Photo credit: NASA

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