Chris Mooney reports on science and the environment.
It seems doubtful that we can defend all of the many coastal zones that will be at risk. So is there any other way to head off sea level rise?
It may sound ridiculous to even contemplate. But in a new study just out in the open access journal Earth System Dynamics, scientists have actually published an idea for doing that and provided some calculations regarding the scale of what it would take. That scale turns out to be simply massive, ultimately rendering the idea about as unfathomable as the oceans themselves.
But then, that’s kind of the point.
“This is not a proposition,” said Anders Levermann, a sea-level expert at the Potsdam Institute for Climate Impact Research and one of the study’s authors. “It’s a discussion. It’s supposed to initiate the discussion on how big the sea level problem really is.” The paper was composed by Levermann and fellow researchers Katja Frieler and Matthias Mengel.
Their idea, simply put, is to pump excess seawater more than two miles into the air to the top of the Antarctic ice sheet, where it would freeze and stay put — for a very long time, although not forever. The new study, accordingly, uses a computer model of Antarctica to study the consequences of adding huge volumes of salt water to different portions of the ice sheet.
And there turn out to be a few, er, problems: the unfathomable amount of energy required and the massive geoengineering of what is arguably the only truly unspoiled place on Earth. Accordingly, the Potsdam Institute itself has framed the research as backing the idea that “future sea-level rise is a problem probably too big to be solved even by unprecedented geo-engineering.”
The problem with using geoengineering to counter rising seas is that every millimeter of sea level rise is equivalent to 360 billion tons of ocean water. And seas are currently rising at a rate of over 3 millimeters per year, with the rate of increase expected to grow still further in the future.
The modeling study suggests that pumping water deep into the center of Antarctica, 700 kilometers inland and over two miles into the air, would indeed keep it there for a good while. Here, the addition of one meter’s worth of sea level rise would translate into raising the total elevation of continental ice by 25 meters.
If you pump water to this exceedingly remote, freezing place, said Levermann, then in 1,000 years, only about 20 percent of its equivalent will return to the ocean, through the gradual spreading and flow of Antarctic ice out toward the sea under its own massive weight. So in effect, Antarctica would indeed store sea level rise (so long as you keep on pumping).
Still, there’s an enormous catch. You would be moving so much water that merely to lift 3 millimeters’ worth of sea level rise annually, the amount of energy required would amount to 7 percent of all the energy that the world generates, the study calculates. To pump even more water as sea level rise accelerates, you’d need even more energy.
Moreover, you’d have to do all of this in an exceedingly remote place where right now, there’s nothing like the capacity to generate that much power.
Therefore, the research finds, you’d also have to install 850,000 wind turbines around Antarctica — “the windiest place on the planet,” Levermann observed. Collectively, these turbines would generate a steady stream of 1,275 gigawatts (or billion watts) of electricity. This would amount to tapping into 8 percent of Antarctica’s total wind energy potential, the study says. (For reference, the total U.S. electricity generating capacity in 2012 was just 1,063 gigawatts.)
For the pumping, meanwhile, you would need “90 of the largest pump stations currently under construction in New Orleans,” each of which would be capable of pumping 360 cubic meters of water per second, the study calculates.
“The scope of such a project is unprecedented and would require major technical innovations, if possible at all,” the study says. “Therefore, costs cannot be reliably estimated.”
“There are a million problems associated with this method that we haven’t even been able to study,” said Levermann bluntly. That includes the problem of adding large volumes of saltwater on top of a freshwater ice sheet, with unknown consequences.
The research also notes that such a massive human intervention would undoubtedly despoil Antarctica’s uniquely preserved coastal ecosystems and, thus, violate the Antarctic Treaty.
The scale of this proposal is, in the end, self-refuting — which, again, is part of the point. Still, the fact that the idea has actually been published in a peer reviewed journal gives a sense, perhaps, of where we now find ourselves.
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Chris Mooney reports on science and the environment.
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