The most down-to-earth idea is that proposed by John Latham, a scientist at the National Centre for Atmospheric Research in Colorado. He suggests that blasting tiny droplets of seawater into the air would stimulate the formation of highly reflective, low-lying marine cloud. Simulations suggest this would have a substantial cooling effect. The question is how to do it economically. Stephen Salter of the University of Edinburgh has designed an unmanned vessel which would produce these clouds using wind power. Just 50 vessels, he reckons, each costing a few million dollars and spraying around 10kg (22lb) of water per second, could cancel out a year's worth of global carbon-dioxide emissions—though another 50 vessels would be needed every year until carbon-dioxide emissions were under control.Interesting. Take some water vapor shoot it in the air and reduce the impact of glacier melting and hurricanes. Might even help bring rain to areas in droughts. I don't know if it will work, but for a couple of million dollars I would definitely like to see it tried.
Dr Salter's ships would be much more precise than other geo-engineering schemes—“like an artist's paintbrush”, as he puts it. They could be deployed to the North Atlantic to cool the Greenland ice sheet during the northern summer and then migrate to Antarctica for the southern summer. Dr Caldeira even suggests that by cooling the sea, these ships could be used to combat hurricanes, since high sea-surface temperatures are linked to hurricane formation.
via The Economist and more info at New Scientist