Scientists are warning that the Western Antarctic Ice Sheet (WAIS) may have already become unstable enough to cause global sea levels to rise by 3 meters (10 feet).
In a 2014 study led by Eric Rignot, a NASA glaciologist, he warned that the ice in the WAIS had already gone into an irreversible retreat. He considered the melting “unstoppable,” and could raise the sea level by 1.2 meters (4 feet).
In a new study this year, researchers from Germany’s Potsdam Institute for Climate Impact Research have pointed out the long-term impacts of the Amundsen Sea sector of West Antarctica, which they said “has most likely been destabilized.”
While in the previous study they had “examined the short-term future evolution of this region, here we take the next step and simulate the long-term evolution of the whole West Antarctic ice sheet,” Anders Levermann, lead author of the study, said.
The researchers used a computer model to gain a more long-term and larger-scale prediction. What they found was if conditions don’t change by 2075, it “would drive the West Antarctic ice sheet past a critical threshold beyond which a complete, long-term disintegration would occur.”
Levermann, professor of climate dynamics at the Potsdam Institute for Climate Impact Research in Germany, said: “We now, for the first time, show that if you destabilize the region, then you get a chain reaction, and the entire WAIS is discharged into the ocean.”
According to D News, the WAIS accounts for only about 10 percent of the entire Antarctic ice continent, and it could take several hundred to thousands of years for the entire WAIS to melt, Leverman said.
‘We can now say how much sea level rise that will imply, which is 9.8 feet, but it will take a long time.’
“If the destabilisation has begun, a 9.8 foott (3 meter) increase in sea level over the next several centuries to millennia may be unavoidable,” Levermann wrote.
Rather than just the small area of the two glaciers that are currently retreating, the computer model used took into account conditions on the entire continent, Levermann told D news. This is why the time scales are not exact, but the results are.
“We can say that to our knowledge there is nothing that will hold [the ice sheet] once it is destabilized,” Levermann said. “And it’s unlikely that once this will happen, that it will stop.”
Levermann however did explain the model needed more observational data on the topography of the ice surface, and required more information about the bedrock upon which the WAIS sits. It is necessary to know the frictional forces between the ice and the rock underneath to gain a better understanding on how quickly the ice will break up, wrote D News.
Jay Zwally, a glaciologist with NASA, whose study was published just days before this study, showed that the Antarctic ice had gained mass, and had enough to exceed the amount lost in other areas.
“We’re essentially in agreement with other studies that show an increase in ice discharge in the Antarctic Peninsula and the Thwaites and Pine Island region of West Antarctica,” Zwally said in a statement.
“Our main disagreement is for east Antarctica and the interior of West Antarctica — there, we see an ice gain that exceeds the losses in the other areas.”
Rignot told ABC that the German model just added more proof that Antarctica is in trouble.
“It adds to the critical debate of how long it will take for ice to retreat from West Antarctica,” Dr Rignot said. “The real advance here is to put on the table yet another model projection that shows very rapid retreat, i.e., less than 100 years.”