Original URL: http://www.theregister.co.uk/2012/10/02/asteroid_to_battle_climate_change/

Boffins suggest orbital dust-up to combat climate change

Let's park an asteroid beyond the moon

By Richard Chirgwin

Posted in Science, 2nd October 2012 03:00 GMT

A researcher from Scotland’s University of Strathclyde has suggested what looks to El Reg like a fairly radical proposal to combat climate change: asteroid dust.

The PhD research student, Russel Bewick, at the university’s Advanced Space Concepts Laboratory, has put the idea to LiveScience ahead of the publication of a paper due in the November 12 issue of Advances in Space Research.

The proposal would work like this: a large enough asteroid manoeuvred into Earth orbit at the L1 Lagrange point would capture and maintain a dust cloud sufficient to reduce the amount of heat we receive from the Sun.

As Bewick explained to LiveScience, the problem with geo-engineering proposals based on orbiting dust is that it would disperse over time. With an asteroid to act as a gravitational anchor, this dispersal problem would be overcome.

Bewick’s suggested target is enough dust to cut the incident solar radiation by 1.7 percent – enough to offset a 2°C rise. “A 1.7 percent reduction is very small and will hardly be noticeable on Earth”, he told LiveScience.

The L1 Lagrange point is about four times the distance from Earth to the Moon – much further than many near-Earth asteroids passing us. An asteroid with the mass of the near-Earth Ganymed 1036 would, he calculates, anchor as much as 5 million billion kilograms of dust, which at 6.58 percent of solar radiation blocked would far exceed the amount Bewick suggests.

There’s currently no technology on offer to relocate something as big as Ganymed’s 130 million billion kilos, so Bewick suggests moving smaller asteroids into a cluster at L1.

Bewick emphasised that geo-engineering should be seen as a “buy time” strategy rather than a solution to global warming. ®