When I was a boy in the 1930s, the carbon dioxide level was still below 300 parts per million. This year, it reached 382, the highest figure for hundreds of thousands of years.

No one will protect what they don't care about, and no one will care about what they have never experienced.

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.

Instead of controlling the environment for the benefit of the population, perhaps we should control the population to ensure the survival of our environment

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

Anyone who believes in indefinite growth on a physically finite planet is either mad or an economist

The World is full of wonders, but they become more Wonderful, not less Wonderful when Science looks at them.

The question is, are we happy to suppose that our grandchildren may never be able to see an elephant except in a picture book?

How could I look my grandchildren in the eye and say I knew what was happening to the world and did nothing.

Bringing nature into the classroom can kindle a fascination and passion for the diversity of life on earth and can motivate a sense of responsibility to safeguard it.

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

I was raised with a sense of democratic vistas and egalitarianism.

There is enough oil out there for world demand. It is true that a lot of what's driving oil prices up right now is not the lack of supply. There's enough supply.

I sort of don't remember anything I did in the '70s.

After each creative act one has to be sustained by one's strength of character, by a moral sense, by I don't know what, lest one tumble.

The irony is that you can't use real rain to make movies.

Happiness is discovering the prune juice your doctor ordered you to drink has fermented.

Of course, [Adolf] Hitler was a dilettante, but he was a completely amoral person. Yes, he had no morals at all.

Nothing is so swift as calumny, nothing is more easily propagated, nothing more readily credited, nothing more widely circulated.

I suddenly realized I was racing around so much, I could never catch up with my life