To Avoid Sea Level Rise, Some Researchers Propose Barriers Around the World's Vulnerable Glaciers

"Researchers are proposing a new way to battle the effects of climate change..." writes Science magazine: slowing the rising of sea levels with "glacial geoengineering". (That is, "building flexible barriers around them or drilling deep into them to slow their slippage into the sea.")Geoengineering proponents say it would be better to begin research now on how to staunch sea level rise at its source, rather than spending billions and billions of dollars to wall off coastal cities. "At some point you have to think, 'Well, is there anything else we can do?'" asks glaciologist John Moore of the University of Lapland, an author on the white paper, which was sponsored by the University of Chicago. One idea researched by Moore and covered in the report is to build buoyant "curtains," moored to the sea floor beyond the edge of ice shelves and glaciers, to block natural currents of warm water that erode ice sheets from below. (Especially in Antarctica, warming ocean water is a bigger threat to glaciers than warming air.) Early designs called for plastic, but natural fibers such as canvas and sisal are now being considered to avoid pollution concerns. According to the white paper, initial modeling studies show that curtain heights stretching only partway up from the sea floor off the coast of western Antarctica could reduce glacial melting by a factor of 10 in some locations. Another intervention some scientists are contemplating would slow the slippage of ice sheets by drilling holes to their bases and pumping out water or heat. Such massive engineering efforts would surely be some of the most expensive ever undertaken by humanity. At a workshop at the University of Chicago in October 2023, researchers suggested it might cost $88 billion to build 80 kilometers of curtains around Antarctic glaciers. Interventions would also require international political support, which some glaciologists view as an even bigger hurdle than the price tag. Twila Moon, a glaciologist at the U.S. National Snow and Ice Data Center, says such projects would require fleets of icebreakers, extensive shipping and supply chain needs, and significant personnel to construct, maintain, and guard the final structures - in ocean conditions she calls "eye-poppingly difficult." The projects could also incur unintended consequences, potentially disrupting ocean circulation patterns or endangering wildlife. Furthermore, it would take decades to find out whether the interventions were working. Even if the engineering and logistics were possible, that "does not answer the question of whether it should be pursued," says Moon, who opposes even preliminary studies on the concepts. "The report, which also stresses the importance of emissions reductions, takes pains to say it 'does not advocate for intervention; rather, it advocates for research into whether any interventions may be viable'..."

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