I have no doubt that the fundamental problem the planet faces is the enormous increase in the human population

I would be absolutely astounded if population growth and industrialisation and all the stuff we are pumping into the atmosphere hadn't changed the climatic balance. Of course it has. There is no valid argument for denial.

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?

This last chapter .. may have given the impression that somehow man is the ultimate triumph of evolution, that all these millions of years of development have had no purpose other than to put him on earth. There is no scientific evidence whatever to support such a view and no reason to suppose that our stay here will be any more permanent than that of the dinosaur.

I'm luckier than my grandfather, who didn't move more than five miles from the village in which he was born.

The truth is: the natural world is changing. And we are totally dependent on that world. It provides our food, water and air. It is the most precious thing we have and we need to defend it.

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.