
Last year a team of Harvard scientists had an idea involving a large balloon and a small amount of chalk dust. They devised an experiment in which a weather balloon would release less than 2 kilograms of calcium carbonate about 12 miles above a Swedish Space Corporation facility near the arctic town of Kiruna, or possibly a tiny quantity of sulfate particles, equivalent to the amount released in a single minute by a typical commercial aircraft.
These plans were greeted with utter panic. Activist groups declared the "risks of catastrophic consequences" were too great, and there were "no acceptable reasons" for allowing the project to go forward. Experimenting with this technology, they claimed, has "the potential for extreme consequences, and stands out as dangerous, unpredictable, and unmanageable." The Swedish government canceled the tests.