For how many people do you think might yet stand on this planet before the sun grows cold? That's the responsibility we hold in our hands.

We still need conservationists who will attempt the impossible, achieving it because they aren't aware how impossible it is.

You don't need it, but will you take some advice from a Californian who's been around for a while? Cherish these rivers. Witness for them. Enjoy their unimprovable purpose as you sense it, and let those rivers that you never visit comfort you with the assurance that they are there, doing wonderfully what they have always done.

It seems that every time mankind is given a lot of energy, we go out and wreck something with it.

At that time a senator who was on the Joint Committee of Atomic Energy said rather quietly, 'You know, we're having a little problem with waste these days.' I didn't know what he meant then, but I know now.

If you want to get people off drugs, improve reality.

What we are finding out now is that there are not only limits to growth but also to technology and that we cannot allow technology to go on without public consent.