Can trillion-tonne snow cannons save us from sea-level rise?

Greek Peak Ski Resort snowmaker John Murphy trudges through ankle deep artificial snow as he checks snowmaking machines on the Virgil N.Y. resort's Alpha Slope in 2000

Greek Peak Ski Resort snowmaker John Murphy trudges through ankle deep artificial snow as he checks snowmaking machines on the Virgil N.Y. resort's Alpha Slope in 2000

Using their model, the researchers artificially enhanced snowfall in these regions, finding that the resulting increase in ice surface elevation near the point at which the glaciers meet the ocean effectively stabilizes the shelf and leads to a two to five-centimeter sea level drop (assuming water for the snowfall is taken from the ocean). Simulations show that the ice sheet is already melting and could cause sea levels to rise up to more than 3 meters, putting populous coastal cities such as New York, Calcutta, Shanghai, and Tokyo at risk.

Spraying trillions of tons of snow over western Antarctica may halt the ice sheet's collapse and save coastal cities across the world from sea level rise, according to new research.

"The apparent absurdity of the endeavour to let it snow in Antarctica to stop an ice instability reflects the breath-taking dimension of the sea-level problem", concludes Levermann.

And as planet-warming emissions continue to rise despite the Paris agreement on climate change, awareness is growing that limiting temperature rises to under 2.0 degrees Celsius (3.6 Fahrenheit) - the treaty's cornerstone goal - may be insufficient to avert disaster.

Geo-engineering schemes - large-scale, deliberate intervention in Earth's climate - have garnered much attention in recent years, such as injecting particles into space or storing Carbon dioxide in the ground.

But few have addressed the issue of sea-level rises, which is likely to cause more human misery than just about any other climate impact. Researchers at the Potsdam Institute for Climate Impact Research (PIK) have published a study in Science Advances examining the possibility of physically generating supplementary snowfall from ocean water and distributing the icy slush via snow cannon.

"W$3 e find that an very bad lot of snow can indeed push the ice sheet back towards a stable regime and stop the instability", said co-author Johannes Feldmann.

The colossal geoengineering project would need energy from at least 12,000 wind turbines to power giant seawater pumps and snow cannons and would destroy a unique natural reserve.

Levermann also points out that the plan is only a hypothesis and that to have any chance of success, it should be accompanied by radical cuts in gas emissions that contribute to global warming.

Such a project has not been costed and would require "something resembling an Antarctic moon station" with years of round-the-clock work, Levermann said. Underwater melting of these glaciers caused the largest ice loss from the continent and accelerated global sea level rise.

Pervious geo-engineering options to stave off West Antarctic melt have included constructing Eiffel Tower-sized columns on the seabed to prop up the ice shelf, and a 100m-tall, 100-kilometre-long berm to block warm water flowing underneath. "There's no place on earth that's protected on that scale", he said.

"So we either build our coastal protections as high as five metres worldwide, or do something insane like this".