The hurricane stoppers / David Bailo

Tropical cyclones are the strongest storms in nature. Is it possible to stop them?

After another active Atlantic hurricane season subsided in the fall of 2011, some atmospheric scientists claimed they had tools to stop or slow down these powerful storms. But their efforts are hampered by a lack of funding and complicated legal issues.

Until recently, the US Department of Homeland Security was researching the possibility that seeding storm clouds with particles similar in size to pollutant aerosols (particles suspended in the air) might slow down tropical cyclones. Computer simulations showed that aerosol seeding may have "a significant effect on the strength of a tropical cyclone, " So wrote William Cotton, an atmospheric scientist at Colorado State University. He and his colleagues recently reviewed the In fact, human-generated pollution may already be weakening these storms, such as in the case of Hurricane Irene in August 2011. "All the [computer] models predicted that Irene would be much stronger than that actually happened," says Cotton. "Did it happen because they didn't take into account the effect of aerosol particles?"

Other people who claim to stop hurricanes in the future, including the founder of Microsoft, the billionaire Bill Gates, have focused on the idea of ​​feeding the warm storms with cold water to stop their momentum. The plan that Gates supports proposes using a fleet of barges, powered by the force of waves, to spread cold water on the surface of the sea in the path of the intensifying storm that will be drawn from the cooler depths of the ocean. The disadvantage of this program is that it can be cumbersome. Hundreds of installations would be needed, and placing them could be challenging given that it is very difficult to track the direction of a storm. But the idea will soon face an indirect test in Hawaii. The US Navy plans to place a prototype of a facility to produce energy that originates from the temperature difference between the water on the surface of the sea and the water in the depths. The facility will pump cold water to the surface of the ocean similar to what would be required to stop a typhoon.

But is dissipating storms using cold water even a good idea? Despite their destructive power, tropical storms are one of the ways in which heat energy is redistributed on Earth from the equatorial region to the poles. Closing that path could have unintended consequences, and diverting the storm from its path could punish people in the new path, as a team of engineers, public policy experts and atmospheric scientists wrote in the Journal of Environmental Science and Technology in April 2011.

Despite their tremendous power, tropical cyclones are sensitive to environmental conditions. To take advantage of this sensitivity, scientists will need accurate information about the future direction of the storm, says meteorologist Ross Hoffman of Atmospheric and Environmental Research (AER). But the US administration is cutting budgets for the satellites needed for the surveillance that would allow such a prediction. For now, flood zone maps and evacuation plans remain the best way to protect North American residents.