Only Controllable Geo-engineering, Please!

I understand T Homer-Dixon and D Keith when they state that it is better to study global-warming-related geo-engineering now rather than waiting to do it in a frenzy if disaster strikes (“The ultimate sun-block“, IHT, October 6, 2008).

What I do not understand, is their interest in “flooding the atmosphere with manmade particles“.

Throwing colossal amount of particles more or less at random in the sky, with no chance of retrieval should they overdo on their original goal, is surely a recipe for global environmental upheavals far more certain than anthropogenic global warming.

The important thing is to get scientists, environmentalists and global-warming skeptics alike” to concentrate on geo-engineering systems we can control, starting with systems that we can switch on and off at will (like for example an orbiting “sun-shade”).

Especially if climate change turns out to be incontrollable, to introduce yet more incontrollable factors would be akin to trying to repair a car by banging a hammer against it at random points.