Nathan Myhrvold and the Next "Smart" Thing - WSJ.com

MR. MYHRVOLD: The first thing that is not obvious to people is global warming is a less-than-1% effect. It's like being shortchanged at the bank by a penny every dollar. Over a long period of time with lots of transactions, that piles up.

It's hard to predict with perfect accuracy, hard to predict what effect that will have on Earth. The speculation includes things that could be catastrophic, like, oh, Greenland falls into the water. Now there's some people that think that's absolutely going to happen. There's some people that think that's highly unlikely. We don't actually know enough about the physics of that, because we haven't watched it.

MR. MURRAY: So the solution is?

MR. MYHRVOLD:The most dramatic approach is to say, "Can we cool Earth off?" The answer to that, surprisingly, is yes. And the reason goes back to it being a 1% effect. All you have to do is reflect 1% roughly of the light that hits Earth before it comes down, and you've solved the entire problem. It was recognized in the 1960s that sulfur dioxide does this naturally in the atmosphere. For relatively modest amounts of sulfur dioxide injected into the atmosphere, you could easily cool Earth by 1% or more, if you want.