Trails are relatively inexpensive. A splendid national network of all kinds of trails can be established at less cost than a few hundred miles of super highway.

I think the internal combustion engine will disappear from the streets of our cities in the next thirty years because transportation will be mass transportation, or probably electrical power.

All economic activity is dependent upon that environment and its underlying resource base of forests, water, air, soil, and minerals. When the environment is finally forced to file for bankruptcy because its resource base has been polluted, degraded, dissipated, and irretrievably compromised, the economy goes into bankruptcy with it.

The bigger the population gets, the more serious the problems become... We have to address the population issue. The United Nations, with the U.S. supporting it, took the position in Cairo in 1994 that every country was responsible for stabilizing its own population. It can be done. But in this country, it's phony to say 'I'm for the environment but not for limiting immigration.'

If we continue to address the issue of the environment where we live as though we're the only species that lives here, we'll create a disaster for ourselves

It was truly an astonishing grassroots explosion, ... The objective was to get a nationwide demonstration of concern for the environment so large that it would shake the political establishment out of its lethargy.

The fate of the living planet is the most important issue facing mankind.