There was almost a universal acceptance of unhealthy conditions. Sulfur dioxide in smokestack emissions were the price, or smell, of prosperity.

Asbestos, EMFs, and CFCs have given us a degree of humility. When yesterday's "triumph of modern chemistry" turns out instead to be today's deadly threat to the global environment, it is legitimate to ask what else we don't know.

When we held the first Earth Day, everyone said it was a success because of the huge turnout. It was probably the largest planned event across the country.

The more subtle thing is more speculative. The world is well past its long-term carrying capacity for human beings living a European, much less an American, lifestyle predicated on planned obsolescence. International economic growth is largely a matter of accelerated movement of materials from mines and forests to the dump. Instead of saving and buying decent furniture we can pass on to our children, we charge our credit cards for shaped heaps of sawdust and glue that fall apart in less than three or four years.

We shouldn't fuel the future with the polluting methods of the past, ... We have the technology to power our future in ways that don't threaten our health or poison our planet. Let's choose to use it.

Earth Day gathered up those strands, and dozens more, and knitted them together in the public consciousness as "environmental" issues. The nation was pretty startled when 20 million people hit the streets. Congress, which had adjourned for the day to go back to its districts, was blown away.

These are not exhortations from overwrought extremists, but carefully phrased warnings from some of the world's finest scientists.