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

We presently have the technology ... fuel cells, solar cells, hydrogen ... the opportunities are amazing for clean energy.

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.

By the year 2000, such renewable energy sources could provide 40 percent of the global energy budget; by 2025, humanity could obtain 75 percent of its energy from solar resources.

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

Listen up, you couch potatoes: each recycled beer can saves enough electricity to run a television for three hours.

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.