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

If we were all to reduce our demands for energy, it would make an enormous amount of difference.

It seems to me that the natural world is the greatest source of excitement; the greatest source of visual beauty; the greatest source of intellectual interest. It is the greatest source of so much in life that makes life worth living.

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

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.

Well, I'm having a good time. Which makes me feel guilty too. How very English.

The correct scientific response to something that is not understood must always be to look harder for the explanation, not give up and assume a supernatural cause.