Scientists Propose Ambitious Geoengineering Projects Aimed at Delaying Catastrophic Sea Level Rise

Continued warnings that a key glacier in West Antarctica is at serious risk of collapse has prompted a debate over using geoengineering as a way of slowing the ice sheet’s rate of melt, using artificial barriers to shield the vulnerable ice shelf from warm water that is eroding it from below: would such a project help delay runaway sea level rise, or might it do more harm than good?

The glacier in question, the Thwaites Glacier, is a key component in the system of glaciers that flow across West Antarctica: although Thwaites itself holds enough ice to raise sea levels by an estimated 60 centimeters (24 inches) if it were to melt entirely, the glacier also acts a plug for the other ice flows that surround it, and if it were to fail it could trigger a cascading collapse of ice into the ocean that would result in a 3.3-meter (10-foot) increase in sea levels—hence Thwaites’ foreboding nickname of ‘The Doomsday Glacier’.

Although progress has been made in the reduction of carbon emissions since the 2015 Paris Accords, this has not erased the ongoing warming experienced by the planet, including the absorption of the majority of the excess heat by the oceans; while glaciers around the world have been melting from above by increased air temperatures, ice shelves, like Thwaites and its West Antarctica neighbors, have been eroded from underneath by increasingly warmer water, increasing the odds they will lose their footing on the bedrock that supports them, potentially sending billions of tons of ice crashing into the sea.

That brings us to the idea of using geoengineering, in the form of underwater barriers, as a stop-gap measure to prevent the warmer water from reaching the ice shelves while the world tackles the overall problem of global warming: the Seabed Curtain project would see the installation of such barriers installed along the floor of the Amundsen Sea opposite the Thwaites and Pine Island glaciers, either in the form of fabric curtains, or possibly as simple as a network of pressurized pipes that emit a curtain of bubbles, intended to prevent warmer water from offshore from reaching the glacier face to begin with, while also retaining the cooler meltwater that runs off of the glacier itself.

Because the warm ocean currents that are causing the problem flow in deeper waters, a fabric curtain, anchored to the seabed, would not have to rise all the way to the surface, allowing the communication of calved icebergs and marine animals, oxygen and other components over the barrier. Additionally, the barrier wouldn’t need to be continuous along the entirety of the glacier’s face.

“We are not going to do this with a single sheet of fabric, and we are not looking at perfect, sealing membrane,” explained one of the authors of the Seabed Curtain project, Shaun Fitzgerald, who is also the director of the University of Cambridge’s centre for climate repair.

Regardless of whichever form this barrier might take, such a project would be a herculean feat of engineering: over 100 kilometers (62 miles) of barrier would have to be constructed not only on the ocean floor, but in a region that is notoriously difficult to merely access when seasonal conditions are favorable.

There is also the problem that a project like Seabed Curtain might create the misperception amongst the public and policymakers that such a barrier will prevent sea level rise, and eliminate the need to address the root of the global warming problem, namely human-based carbon emissions.

“When we talk about glacial geoengineering, we need to tell the truth, which is that it’s not a solution to climate change—at best, it’s a painkiller,” explained Gernot Wagner, a climate economist in the Columbia Climate School. “It allows us to get out of bed and do what is necessary to address the underlying illness while taking the edge off the worst of the pain.

“[But] geoengineering doesn’t solve anything, so we need to use the time it gives us to address emissions.”

But if projects like Seabed Curtain are to move forward, study into their respective constructs’ potential impacts needs to start immediately, considering the clock of global warming has already been ticking for many years. According to Seabed Curtain report co-author John Moore, a professor with the Arctic Center at the University of Lapland, “it will take 15 to 30 years for us to understand enough to recommend or rule out any [glacier geoengineering] interventions.”