People have to decide, first of all, how they'd like to live, and how secure they want to be from disaster. After that, scientists can help determine what would be necessary to achieve that.

I kind of like carbon taxes because we already know how to apply them. We already have apparatus in place. When we talk about these other solutions - like a billion tons of iron filings in the ocean or putting sunshades between us and the sun - they're huge. We have no idea if they will work. We have no idea what their nasty consequences might be. And it's unlikely we can do them anyway.

In pushing other species to extinction, humanity is busy sawing off the limb on which it perches.

The main thing is, and of course this is a pedant talking, we should start our education on these issues in kindergarten. Instead of saying, "See Spot run," we ought to say, "See the plant grow in the sun." We ought to explain what runs the weather in the third or fourth grade to start out with.

If we were redesigning around people instead of around automobiles, which I think the market is more or less going to do, although too slowly, than I'd be a lot cheerier.

With taxes, if they aren't working right, we can change them with a stroke of the pen. It's basically a market-type mechanism. People make their own choices. You run the taxes, and you get the results.

Chinese are already more on board than we are. China is the only country that actually discussed in formal government documents how important it is to control the size of your populations if you’re going to limit emissions.