Russell Bewick, a space scientist at the University of Strathclyde, has suggested a scheme to combat climate change using asteroid dust to screen solar radiation. A near-Earth asteroid would be placed at the Earth-Sun Lagrange-1 (ESL-1) point and fitted with a mass-driver to spew asteroidal dust into space. The dust would settle in the weak gravitational well created by the asteroid as a cloud around 2600km across. Pulverising 5 per cent of the asteroid 1036 Ganymed would generate around 5 trillion tonnes of dust, and block 6.58 per cent of incident solar radiation at the Earth.

• Asteroid Dust Could Fight Climate Change on Earth -- LiveScience

Rocketeer comments: Have to say that I regard geoengineering "solutions" as a monstrous waste of money at best, and actively bloody dangerous at worst.

Manipulation of a highly complex and poorly understood system is a classic opportunity for the Law of Unintended Consequences. What happens if the asteroidal dust is deployed, and the Sun then goes into a prolonged minimum of activity, causing an unanticipated extra drop in temperature? It's not as if you can turn the dust off again with any speed. Where you can turn a geoengineering system off again, you don't understand all the time constants in the system, and run the risk of setting up induced climate oscillations, making the whole thing worse not better...