Without the heart to ground it and open it to who we really can be as human beings, the brain is a very dangerous machine. A machine that is saying: we've got to have economic growth; we've got to have unending economic growth, otherwise societies will collapse. And yet there should be something saying: wait a minute, this isn't going to work.

Chimps are unbelievably like us - in biological, non-verbal ways. They can be loving and compassionate and yet they have a dark side... 98 per cent of our DNA is the same. The difference is that we have developed language - we can teach about things that aren't there, plan for the future, discuss, share ideas

We have to create more and more vegetarians, and help people to understand that it is not only the suffering of the animals (which is what made me vegetarian) but also the incredible harm to the environment, the tremendous amount of greenhouse gas created by the whole vast machinery of intensive animal farming.

And I thought how sad it was that, for all our sophisticated intellect, for all our noble aspirations, our aggressive behavior was not just similar in many ways to that of the chimpanzees - it was even worse. Worse because human beings have the potential to rise above their baser instincts, whereas chimpanzees probably do not.

Language allows us to talk about the past and plan the future. We can teach children about things that are not present. And above all, we can bring people with different backgrounds and different knowledge together to discuss our problems. This actually gives me hope. I still think we are smart enough to not destroy planet Earth, our only home.

If you look into their [chimpanzees] eyes, you know you're looking into a thinking mind. They teach us that we are not the only beings with personalities, minds capable of rational thought, altruism and a sense of humor. That leads to new respect for other animals, respect for the environment and respect for all life.

My mission is to create a world where we can live in harmony with nature. And can I do that alone? No. So there is a whole army of youth that can do it. So I suppose my mission is to reach as many of those young people as I can through my own efforts.