You've got to be fairly solemn [about the environment]. I mean the mere notion that there are three times as many people on Earth as there were when I started making television. How can the Earth accommodate them? When people, including politicians, set their faces against looking at the consequences-it's just unbelievable that anyone could ignore it.

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.

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

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.

The World is full of wonders, but they become more Wonderful, not less Wonderful when Science looks at them.

The whole of science, and one is tempted to think the whole of the life of any thinking man, is trying to come to terms with the relationship between yourself and the natural world. Why are you here, and how do you fit in, and what's it all about.

If we and the rest of the back-boned animals were to disappear overnight, the rest of the world would get on pretty well. But if the invertebrates were to disappear, the world's ecosystems would collapse