johkir writes "As early as 1965, when Al Gore was a freshman in college, a panel of distinguished environmental scientists warned President Lyndon B. Johnson that CO2 emissions from fossil fuels might cause 'marked changes in climate' that 'could be deleterious.' Yet the scientists did not so much as mention the possibility of reducing emissions. Instead they considered one idea: 'spreading very small reflective particles' over about five million square miles of ocean, so as to bounce about 1 percent more sunlight back to space — 'a wacky geoengineering solution.' In the decades since, geoengineering ideas never died, but they did get pushed to the fringe — they were widely perceived by scientists and environmentalists alike as silly and even immoral attempts to avoid addressing the root of the problem of global warming. Three recent developments have brought them back into the mainstream." We've discussed some pretty strange ideas in the geoengineering line over the last few years.