Can we slow sea level rise by pumping water onto Antarctica?
Researchers investigate the feasibility of a 'geoengineering' solution to rising sea levels: pumping vast quantities of ocean water onto the continent of Antarctica, to thicken the ice sheet.
Since humans are responsible for changing the global climate, what lengths should we go to to mitigate the damage?
A new study investigates one radical solution: 'geoengineering,' or reshaping the planet in a substantial way. In this case, by enlarging Antarctica's continental glacier via pumping ocean water onto the ice surface. If it works, and the ice sheet grows thicker, it could sequester huge volumes of water and slow or halt the global trend toward rising sea levels.
Geoengineering typically refers to mitigating global climate change either by removing carbon dioxide from the atmosphere or by preventing sunlight from warming the surface by reflecting it back into space.
This approach, thickening the Antarctic ice sheet, would be addressing a symptom instead of the primary drivers of climate change.
“Some argue we shouldn’t even contemplate [geoengineering], as it’s too dangerous to the planet,” says Karen Pinkus, incoming chair of the Faculty Advisory Board at the Atkinson Center for a Sustainable Future, at Cornell University, in a telephone interview with The Christian Science Monitor.
But geoengineering needs to be part of the discussion, says Dr. Pinkus. “Climate change itself is the biggest geoengineering project ever undertaken, anyway, if you take ‘mitigation’ out of the definition.”
The new study, published Wednesday in Earth System Dynamics, used computer simulations to assess the costs and benefits of undertaking the gargantuan task of thickening Antarctica.
“We took quite some time to consider whether to even carry out this research because [Antarctica is] practically the only place humans haven’t interfered with yet,” says climatologist and co-author Anders Levermann, in a telephone interview with the Monitor.
“It’s a very difficult thing to break this taboo and even think about changing Antarctica in a big way,” says the scientist, who heads Global Adaptation Strategies at Potsdam Institute for Climate Impact (PIK) and works at Columbia University's Lamont Doherty Earth Observatory.
The urgency of the situation demands attention, says Dr. Levermann. Even if the far-reaching agreements reached at the Paris climate summit last year are implemented, the seas will rise by as much as four meters, albeit over hundreds of years.
“Sea level rise is not a direct threat to people, but to things, to our cultural heritage, to New York, New Orleans, Toronto, Hamburg et cetera,” continues Levermann. “But this is only true if we adapt. If you have a poor country, it might push this adaptation into the future, and then you may have fatalities…”
He asks, how do we weigh the value of a pristine Antarctica against the populated areas of the world? Should the continent be off-limits?
But independent of whether we should is whether we could.
To determine this, they modeled the ice-covered continent using standard ice flow models. “We put extra snow on certain areas, in the amount we’d need to take out of oceans to avoid sea level rise,” Levermann explains.
They loaded the extra snow onto the eastern section of the continent, where ice floes move the slowest, and varied the snow's location between 50 miles to 400 miles from the coast.
“What we found was that the extra snow created an ice wave, which pushes coastal ice into the ocean,” explains Levermann. “It’s like a sandwich, with the extra pressure squeezing out the mayonnaise.”
The "squeezing" happened even if they dumped the snow hundreds of miles from the coast, although that did slow the process by as much as 1,000 years.
But then came the costs: Pumping the necessary volume of water onto Antarctica, which in some places is coated by an ice sheet 3 miles high, would require seven percent of the global energy supply. Every year.
“At the moment, it looks as though this endeavor would be so huge that it’s not worth the trouble,” says Levermann. “And even if we did it, you would only eliminate the currently observed sea level rise.”
But his job is to gather the data, not make the final call, says Leverman. “It is for society to decide what to do with this information.”