“We are already at a point of no return if we don’t do anything,” stresses climate scientist Anders Levermann. He’s referring to the West Antarctic Ice Sheet, a giant swathe of continental ice sheet that covers West Antarctica.
The West Antarctic Ice Sheet is in the process of melting fast and if it disintegrates sea level will rise by three meters or so worldwide. That will cause low-lying communities and cities like Calcutta, Shanghai, Tokyo and New York to come under threat of being flooded perpetually.
But Levermann and his colleagues at Germany’s Potsdam Institute for Climate Impact Research want to do something about that. “We can bring [the sheet] back to a stable point by a small interference now – or by larger and larger interference later,” the climate scientist says.
Their solution: blast 7.4 trillion tons of artificial snow on top of the ice sheet for a decade. Writing in a study, they envision using tens of thousands of wind turbines to pump seawater to the surface where it would be frozen into trillions of tons of snow. All that snow could then be blasted onto the ice sheet with powerful snow cannons in an effort to try to weigh the sheet down enough to stop it collapsing any further, they explain.
Such a desperate measure might well be necessary, the scientists say, because melting at the vast ice sheet is fast reaching a tipping point. The last time the West Antarctic Ice Sheet retreated so much so fast was 12,000 years ago at the end of the last Ice Age. “The West Antarctic Ice Sheet is one of the tipping elements in our climate system,” Levermann warns. “Ice loss is accelerating and might not stop until the West Antarctic ice sheet is practically gone.”
Warming temperatures are causing once compact ice sheets to crack and fragment, which is increasing the chance that large chunks of them will collapse into the sea. The researchers in Germany used computer simulations to project rates of dynamic ice loss and found that not even reducing our current greenhouse gas emissions significantly might now be enough to save them.
So they started thinking of ways to save the ice sheets artificially. “[W]e find that an awful lot of snow can indeed push the ice sheet back towards a stable regime and stop the instability,” explains Johannes Feldmann, who was a coauthor of the study. “In practice, this could be realized by an enormous redisposition of water masses — pumped out of the ocean and snowed onto the ice sheet at a rate of several hundred billion tons per year over a few decades.”
Yet that’s easier said than done. Nor would such an undertaking be without its drawbacks. “We are fully aware of the disruptive character such an intervention would have,” Feldmann says. Pumping seawater to the surface, desalinating it, and then blasting it away as snow with high-powered snow canons would require a large amount of electricity that would need to be provided by tens of thousands of high-end wind turbines.
“Putting up such a wind farm and the further infrastructure in the Amundsen Sea and the massive extraction of ocean water itself would essentially mean losing a unique natural reserve,” he explains. “Further, the harsh Antarctic climate makes the technical challenges difficult to anticipate and hard to handle while the potential hazardous impacts to the region are likely to be devastating.”
In addition, the project would only work, the scientist points out, if we stopped pumping vast amounts of CO2 into the atmosphere because further increases in global temperatures would cause ice sheets to melt even faster and further.
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