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A Modest Proposal for Stopping Sea Level Rise: Freeze the Ocean

The idea would be to spray seawater over Antarctica, turning it solid for hundreds of years.

A researcher deploys an instrument in meltwater on Greenland. (NASA/Jefferson Beck)

A prepared homeowner knows that when floodwaters start to enter the basement, you use a sump pump to force them back out. Could the same principle be applied to rising sea levels? As oceans threaten to flood coastal communities, could we just pump them down to reasonable heights?

It wouldn’t work if you funneled the oceans to, say, Nebraska, as the water would probably just find its way back out to sea. But fans of grand climate schemes posit pumping it to Antarctica, where it would freeze and presumably stay out of circulation for centuries.

In perhaps a sign of our desperate times, scientists have actually investigated the idea with computer simulations, calculating how much water would need to be pumped, and how much energy it would consume. Researchers at the Potsdam Institute for Climate Impact and Columbia University began by assuming sea levels will rise slightly more than four feet by 2100. For the Big Pump to make an effective dent for 1,000 years, they say, the seawater would need to be dumped at least 435 miles into Antarctica to prevent the newly formed, extremely heavy ice sheets from sliding back into the ocean.

That herculean task would “require more than one tenth of the present annual global energy supply to balance the current rate of sea-level rise,” they explain in a press release. And that’s assuming it could even be done, they add:

The Antarctic ice sheet is up to 4000 meters [or 2.5 miles] high, and that would mean an inconceivable engineering effort. Pumping so much water that high up onto the ice sheet requires enormous amounts of energy. Antarctica is very windy, so the power for the pumping could in principle be generated by wind turbines—yet this would require building roughly 850,000 wind-energy plants onto the ice continent. …

“The magnitude of sea-level rise is so enormous, it turns out it is unlikely that any engineering approach imaginable can mitigate it,” concludes co-author Anders Levermann, head of Global Adaptation Strategies at PIK and scientist at Columbia University’s Lamont Doherty Earth Observatory. “Even if this was feasible, it would only buy time—when we stop the pumping one day, additional discharge from Antarctica will increase the rate of sea-level rise even beyond the warming-induced rate. This would mean putting another sea-level debt onto future generations.” Also, the most sensitive coastal ecosystems of Antarctica would of course be seriously affected by this measure.

Score another blow to the dream of geo-engineering ourselves out of climate change. Perhaps scientists should reinvestigate some of the other engineering proposals, such as planting tons of trees for removing carbon and spraying seawater into the air to spawn temperature-lowering clouds.

About the Author

  • John Metcalfe
    John Metcalfe is CityLab’s Bay Area bureau chief, based in Oakland. His coverage focuses on climate change and the science of cities.