It is that range of biodiversity that we must care for - the whole thing - rather than just one or two stars.

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.

I don't think we are going to become extinct. We're very clever and extremely resourceful - and we will find ways of preserving ourselves, of that I'm sure. But whether our lives will be as rich as they are now is another question.

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.

An understanding of the natural world and what's in it is a source of not only a great curiosity but great fulfillment...

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.

Before the BBC, I joined the Navy in order to travel.