Very few species have survived unchanged. There's one called lingula, which is a little shellfish, a little brachiopod about the size of my fingernail, that has survived for 500 million years, but it's survived by being unobtrusive and doing nothing, and you can't accuse human beings of that.

The nature of human beings is that they'd far rather face the disaster that is happening tonight than the one that is happening tomorrow.

The future of life on earth depends on our ability to take action. Many individuals are doing what they can, but real success can only come if there's a change in our societies and our economics and in our politics. I've been lucky in my lifetime to see some of the greatest spectacles that the natural world has to offer. Surely we have a responsibility to leave for future generations a planet that is healthy, inhabitable by all species

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

All we can hope for is that the thing is going to slowly and imperceptibly shift. All I can say is that 50 years ago there were no such thing as environmental policies.

Can a growing human population still leave space for wildlife?

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