I'm no longer sceptical. I no longer have any doubt at all. I think climate change is the major challenge facing the world.

Instead of controlling the environment for the benefit of the population, perhaps we should control the population to ensure the survival of our environment

I don't know [why we're here]. People sometimes say to me, 'Why don't you admit that the humming bird, the butterfly, the Bird of Paradise are proof of the wonderful things produced by Creation?' And I always say, well, when you say that, you've also got to think of a little boy sitting on a river bank, like here, in West Africa, that's got a little worm, a living organism, in his eye and boring through the eyeball and is slowly turning him blind. The Creator God that you believe in, presumably, also made that little worm. Now I personally find that difficult to accommodate.

Climate change will affect the whole of humanity, while terrorist attacks will only affect a small section of humanity. Of course, you wouldn't say that if you were related to someone who had been beheaded or blown up or murdered. But humanity is facing a very big, slow, long, drawn-out threat, and that is to do with the way the weather is changing and the size of the population.

People talk about doom-laden scenarios happening in the future: they are happening in Africa now. You can see it perfectly clearly. Periodic famines are due to too many people living on land that can't sustain them.

I suffer much less than many of my colleagues. I am perfectly able to go to Australia and film within three hours of arrival.

Natural history is not about producing fables.