Massive subsea walls could be put in place to slow the collapse of ice sheets and contain sea level rise, according to a report published in the European Geosciences Union journal The Cryosphere.
The study’s authors investigated the efficacy of two glacial geoengineering concepts. The first involves building an underwater barrier to prevent warm water from reaching the base of an ice shelf. The second design consists of creating artificial mounds or columns on the sea floor to support a glacier, thereby allowing it to regrow.
The team used computer modelling to apply the concept to Antarctica’s Thwaites glacier, which is rapidly retreating and could trigger and ice sheet collapse that would raise global sea levels by 3m. The results showed that even the simpler of the two designs has a 30 per cent chance of preventing a runaway collapse.
This intervention would consist of building 300m-high mounds or columns on the seabed using between 0.1 and 1.5 cubic kilometres of aggregate. Building a wall would be far more complicated, but if the structure blocked around 50 per cent of warm water, it would have a 70 per cent chance of success.
Despite the encouraging findings, the researchers warn that there are still many engineering details that would have to be worked out before either project could be undertaken.
“We all understand that we have an urgent professional obligation to determine how much sea level rise society should expect, and how fast that sea level rise is likely to come,” says Michael Wolovick, one of the study’s authors and a researcher at Princeton University’s Department of Geosciences. “However, we would argue that there is also an obligation to try to come up with ways that society could protect itself against a rapid ice-sheet collapse.”
While physics show that glacial geoengineering could hold off a catastrophic collapse, Wolovick is adamant that reducing global carbon emissions should be the first priority. “The more carbon we emit, the less likely it becomes that the ice sheets will survive in the long term at anything close to their present volume,” he concludes.