the scheme that launched a thousand (and a half) ships

It should be possible to counteract the global warming associated with a doubling of carbon dioxide levels by enhancing the reflectivity of low-lying clouds above the oceans, according to researchers in the US and UK.

John Latham of the National Center for Atmospheric Research in Boulder, US, and colleagues say that this can be done using a worldwide fleet of autonomous ships spraying salt water into the air.

Latham and colleagues calculate that, depending on exactly what fraction of low-level maritime clouds are targeted (with some regions, notably the sea off the west coasts of Africa and North and South America, more susceptible to this technique than others), around 1500 ships would be needed altogether to counteract a carbon doubling, at a cost of some £1m to £2m each.

This would involve an initial fleet expanding by some 50 ships a year if the scheme is to keep in step with the current rate of increase in atmospheric carbon-dioxide levels.

PhysicsWorld, 4 Sep 2008