There are substitutes for oil; there is no substitute for fresh water.

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.

I see harm reduction as a way of engaging people as part of that path to recovery.

To err is human, but to really foul things up you need a computer.

I thought if the climate was heating that CO2 was the only forcing, and it would be late in the century before we had trouble. Now that we know about the other half of the forcing, it's obvious that the trouble is coming much sooner.

All scientists who've looked at it know we have to phase away from burning fossil fuels. That means we've got to put a lot of effort into alternate energy technologies, but we're still subsidizing fossil fuels and not subsidizing most of the alternatives. It's not going to be an easy transition.

My first policy move would be to try to get a conversation going in the US about what people stand for and what we really want. Do we want to keep adding people to the world and to our country until we move to a battery-chicken kind of existence and then collapse? Or do we want to think hard about what really is valuable to us, and figure out how many people we can supply that to sustainably?