Sentimentalising is anathema, as far as I am concerned. It leads you into ethical problems about violence and killing and eating meat. The whole world becomes topsy-survy if you impose moralities that were evolved within human society on what a blowfly or what a parasite does... there are lots of emotions you can deduce from an animal's behaviour that are correct, but when you start saying it's feeling guilty or thinking or a loved one or mourning, you must be very careful of those feelings.

The human population can no longer be allowed to grow in the same old uncontrollable way. If we do not take charge of our population size, then nature will do it for us and it is the poor people of the world who will suffer most

The only way to save a rhinoceros is to save the environment in which it lives, because there's a mutual dependency between it and millions of other species of both animals and plants.

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

You know, it is a terrible thing to appear on television, because people think that you actually know what you're talking about.

In the West, that's what's happening. The birth rate has been dropping steadily and still is. But there is still a vast amount of the world where that's not the case. And that is where the big population growth is taking place.

One in eight plant species face extinction.