As another active hurricane season in the Atlantic winds down, some atmospheric scientists say they have the tools to stop or slow the powerful storms. Their efforts, however, are hampered by a lack of funding and tricky legal issues.
Until recently, the U.S. Department of Homeland Security has been investigating whether seeding storm clouds with pollution-size aerosols (particles suspended in gas) might help slow tropical cyclones. Computer models suggest that deploying aerosols can have “an appreciable impact on tropical cyclone intensity,” writes William Cotton, an atmospheric scientist at Colorado State University. He and his colleagues recently reviewed such work in the Journal of Weather Modification. In fact, human pollution may already be weakening storms, including August’s Hurricane Irene. “[Computer] models all predicted that the intensity of Irene would be much greater than it was,” Cotton notes. “Was that because they did not include aerosol effects?”
Other would-be storm stoppers, including Microsoft billionaire Bill Gates, have focused on feeding cold water to the hot storms to slow their momentum. The Gates-backed plan proposes using a fleet of wave-powered rafts to spread a slick of colder ocean water pumped up from the depths in the path of an onrushing storm. The trouble with that process is that it could prove unwieldy. It would require hundreds of devices, and because storms are so difficult to track, placing them would be a challenge. The proof of concept will soon get a test of sorts in Hawaii. The U.S. Navy plans to deploy a prototype device that extracts energy from the temperature difference between surface and deep-ocean water. The device will involve pumping cool water to the ocean surface, in much the same manner as would be required to stop a typhoon.
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Would dispelling storms with cold water be a good idea? Tropical cyclones, for all their destructive force, are one of the planet’s ways of redistributing heat from the tropics to the poles. Shutting that down might have unforeseen consequences, and shifting a storm’s course could spawn punitive action from people in the new path, as a team of engineers, public policy experts and atmospheric scientists wrote in Environmental Science and Technology in April.
Regardless, for all their power, tropical cyclones are sensitive. To exploit that sensitivity, scientists would need accurate information on a storm’s future course, says meteorologist Ross Hoffman of Atmospheric and Environmental Research. But the U.S. government is cutting funding for the satellites that make such tracking and prediction possible. For now flood maps and evacuation plans remain our best protection.