If melting continues, the Thwaites Glacier in West Antarctica alone could cause global sea levels to rise 10 feet. James Yungel/NASA
Large-scale geoengineering projects that would involve building walls and berms along the seafloor could help stem the collapse of the West Antarctic Ice Sheet and slow global sea level rise, two scientists contend in a new peer-reviewed study published in the journal The Cryosphere.
Geoscientist Michael Wolovick of Princeton University and climate scientist John Moore of Beijing Normal University examined how various physical barriers could hold back a melting glacier or stop warm ocean water from reaching its underside, the area of a glacier most sensitive to melting. They focused their modeling on the Florida-sized Thwaites Glacier, one of the widest in the world — stretching 50 to 60 miles across — and projected to be the largest individual source of future sea level rise, up to 10 feet globally.
The researchers found that building scattered, 1,000-foot-high mounds or columns of sand or gravel on the seafloor has a 30 percent chance of preventing a runaway collapse of the West Antarctic Ice Sheet for the foreseeable future. A more ambitious project — building a small, continuous wall along the edge of a glacier — could block about 50 percent of warm water from reaching the underside of the ice and has a 70 percent chance of preventing runaway ice sheet collapse within the next 1,000 years.
“The most important result [of our study] is that a meaningful ice sheet intervention is broadly within the order of magnitude of plausible human achievements,” Wolovick said in a statement.
Wolovick and Moore warn, however, that the projects, which they call “glacier geoengineering,” will be massively expensive and time consuming; Antarctica is one of the harshest environments on Earth. And while seafloor barriers may help slow melting from underneath, they won’t do anything about warm air melting the ice from above.
The scientists are also adamant that glacier geoengineering is not a substitute for drastically reducing global greenhouse gas emissions. “There are dishonest elements of society that will try to use our research to argue against the necessity of emissions’ reductions,” the scientists said in a statement. “Our research does not in any way support that interpretation… 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.”
Scientists say building artificial structures on the seafloor, shown here in grey, could prevent warm ocean water from reaching and melting the Antarctic ice sheet from below. Wolovick & Moore, The Cryosphere, 2018
