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.

Steve Irwin did wonderful conservation work but I was uncomfortable about some of his stunts. Even if animals aren't aware that you are not treating them with respect, the viewers are.

If I can make programmes when I'm 95, that would be fine. But I would think I'll have had enough by then.

I just wish the world was twice as big and half of it was still unexplored.

The savage, rocky shores of Christmas Island, 200 miles south of Java, in the Indian Ocean. It's November, the moon is in its third quarter, and the sun is just setting. In a few hours from now, on this very shore, a thousand million lives will be launched.

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

I'm a humanist. I'm neither one side nor the other.