Human beings, because we're so clever, have removed every single one of those population limiting factors... So nothing controls our increase in numbers except our own wish. Since I first started making television programs, the population of the world has increased three times. That's an extraordinary notion. Can it increase four times? Can it increase five times? The Earth is a finite size. So a point will eventually come when we run out of food, when we run out of space and when we will have destroyed most of the natural world. So ought we to do something about it before that happens?

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

I am an ardent recycler. I would like to think that it works. I don't know whether it does or not.

The process of making natural history films is to try to prevent the animal knowing you are there, so you get glimpses of a non-human world, and that is a transporting thing.

The most extraordinary thing about trying to piece together the missing links in the evolutionary story is that when you do find a missing link and put it in the story, you suddenly need all these other missing links to connect to the new discovery. The gaps and questions actually increase - it's extraordinary.

It never really occurred to me to believe in God.

It's extraordinary how self-obsessed human beings are. The things that people always go on about is, 'tell us about us', 'tell us about the first human being'. We are so self-obsessed with our own history. There is so much more out there than what connects to us.