As climate change accelerates, scientists are proposing ever more radical solutions. The latest? Use snow cannons to shoot ocean water onto the Antarctic ice sheet, so that it will re-freeze.
Sea level rise threatens coastal communities around the globe, and will likely intensify an already dire refugee crisis. The potential large-scale melting of West Antarctic glaciers will play a key role in this process, and could dump meters of water on some of the world’s most populous cities.
In a new study published in Science Advances, researchers from the Potsdam Institute for Climate Impact Research model what would happen if we began adding snow to the ice sheet ourselves.
Ice loss from the two glaciers studied—the Pine Island Glacier and Thwaites Glacier—is already Antarctica’s largest contribution to sea level rise. Warmer ocean waters have started melting these glaciers from below, causing them to retreat faster.
To test the theory that we could make it snow in Antarctica, the researchers started by creating models of the West Antarctic ice sheet melting under current conditions and arrived at an uncomfortable conclusion: even the most ambitious emissions reductions schemes won’t be enough to stop these glaciers from melting. Cutting emissions is a necessary step to mitigate further ice melting, but the melting is already set in motion and won’t stop on it’s own.
The researchers ran simulations of the melting glaciers, trying to gauge how much added snow would be necessary to stabilize this ice sheet. They landed on a whopping 7,400 gigatons of snowfall over the course of 10 years. A gigaton is a difficult unit of measure to envision; the Washington Post once described a gigaton as a weight "well over a hundred million African elephants."
If we took that much snow out of the ocean, it would result in a 2 millimeter drop in sea level each year.
The study focused on the theoretical potential of freezing ocean water and dumping it on the ice sheets, but the practical implications are worth exploring. For starters, making it snow in Antarctica using ocean water would require a huge energy expenditure. The average height scientists have to lift the water is 640 meters above sea level. Just getting the water up there would take 145 gigawatts of energy.
Doing this would require roughly 12,000 wind turbines, the researchers estimate.
The water would of course have to be desalinated, and then frozen. Otherwise, scientists would risk creating glacial lakes that could accelerate ice loss or change the flow of the glaciers. The study doesn’t take into account the energy required for either of these processes.
Building these wind turbines and snow cannons would also take a toll on the marine Antarctic ecosystem. The underwater noise, electromagnetic fields, and potential for animals to collide with built infrastructure threaten a unique natural habitat.
"Snowing the water mass onto the ice sheet would mimic the type of precipitation naturally occurring over most part of the ice sheet, demanding a considerable amount of energy and requiring extensive infrastructure for the snow making," the scientists wrote. "
While the study and idea of pumping snow onto Antarctica sounds crazy, it's an idea worth at least considering, and the concept opens up a pretty serious debate.
"Although our findings suggest that the West Antarctic Ice Sheet can in principle be stabilized by mass deposition, we find that the precise conditions of the intervention are crucial, and potential benefits need to be weighed against environmental hazards, future risks, and enormous technical challenges implied in such an operation," the scientists wrote.
Without quick, drastic action, the worst case scenarios of climate change may become reality. These hard choices—between disrupting an entire ecosystem and slowing global sea level rise—will continue to face us.