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.

If I were beginning my career today, I don't think I would take the same direction. Television is at a crossroads at the moment. And although I am not up to date technologically, I suspect that somewhere out there people are conveying things about natural history by means other than television, and I think if I were beginning today, I'd be there.

What humans do over the next 50 years will determine the fate of all life on the planet.

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

Do we really require so many gardening programmes, makeover programmes or celebrity chefs?

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

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.