There are really two kinds of optimism. There's the complacent, Pollyanna optimism that says "don't worry - everything will be just fine" and that allows one to just lay back and do nothing about the problems around you. Then there's what we call dynamic optimism. That's an optimism based on action.

I decided five years ago that I wanted to truly understand, for myself, what the state of the planet was, and when I dug into it, what I found was quite different than I'd imagined.

Often an idea has impact far larger than the person who originated it.

That, to me, is a kind of brilliant environmental ju-jitsu - using the energy of the market and the profit-motive to get businesses to invest in preserving and improving natural systems.

Technology is incredibly powerful. And in many ways, the sky is the limit in terms of what you can actually accomplish with the right science and the right technology.

Whatever my current beliefs are, on any topic, they're all open to being changed by the right facts and the right evidence.

Often we need to use policy to level the playing field, or to be sure that a technology is managed in a responsible way.