David Attenborough

"It's coming home to roost over the next 50 years or so. It's not just climate change; it's sheer space, places to grow food for this enormous horde. Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now."

"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."

"The climate, the economic situation, rising birth rates; none of these things give me a lot of hope or reason to be optimistic."

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

"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."

"I find it far more awesome, wonderful, that creation; our appearance in the world; should be the culmination, or at least one of the latest products of 3,000 Million years of organic evolution, than a kind of country trick, taking a rib out of a man's side in a trance."

"Young people: They care. They know that this is the world that they're going to grow up in, that they're going to spend the rest of their lives in. But, I think it's more idealistic than that. They actually believe that humanity, human species, has no right to destroy and despoil regardless."

"Now, over half of us live in an urban environment. My home, too, is here in the city of London. Looking down on this great metropolis, the ingenuity with which we continue to reshape the surface of our planet is very striking. It’s also very sobering, and reminds me of just how easy it is for us to lose our connection with the natural world. Yet it’s on this connection that the future of both humanity and the natural world will depend. And surely, it is our responsibility to do everything within our power to create a planet that provides a home not just for us, but for all life on Earth."

"‎Using his burgeoning intelligence, this most successful of all mammals has exploited the environment to produce food for an ever increasing population. Instead of controlling the environment for the benefit of the population, perhaps it's time we controlled the population to allow the survival of the environment."

"I don’t know [why we're here]. People sometimes say to me, ‘Why don’t you admit that the humming bird, the butterfly, the Bird of Paradise are proof of the wonderful things produced by Creation?’ And I always say, well, when you say that, you’ve also got to think of a little boy sitting on a river bank, like here, in West Africa, that’s got a little worm, a living organism, in his eye and boring through the eyeball and is slowly turning him blind. The Creator God that you believe in, presumably, also made that little worm. Now I personally find that difficult to accommodate…"