They always mean beautiful things like hummingbirds. I always reply by saying that I think of a little child in east Africa with a worm burrowing through his eyeball. The worm cannot live in any other way, except by burrowing through eyeballs. I find that hard to reconcile with the notion of a divine and benevolent creator.

It's coming home to roost over the next 50 years or so. It's not just climate change; it's sheer space, places to grow food for this enormous horde. Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now.

The more you go on, the less you need people standing between you and the animal and the camera waving their arms about.

All our environmental problems become easier to solve with fewer people and harder - and ultimately impossible to solve - with ever more people.

The climate, the economic situation, rising birth rates; none of these things give me a lot of hope or reason to be optimistic.

I'm luckier than my grandfather, who didn't move more than five miles from the village in which he was born.

Nature isn't positive in that way. It doesn't aim itself at you. It's not being unkind to you.