Finally, since human beings are uniquely capable of producing materials not found in nature, environmental degradation may be due to the resultant intrusion into an ecosystem of a substance wholly foreign to it.

We are in an environmental crisis which threatens the survival of this nation, and of the world as a suitable place of human habitation.

My entry into the environmental arena was through the issue that so dramatically - and destructively - demonstrates the link between science and social action: nuclear weapons.

Environmental quality was drastically improved while economic activity grew by the simple expedient of removing lead from gasoline - which prevented it from entering the environment.

The favorite statistic is that the U.S. contains 6 to 7% of the world population but consumes more than half the world's resources and is responsible for that fraction of the total environmental pollution. But this statistic hides another vital fact: that not everyone in the U.S. is so affluent.

The environmental crisis is a sign that the ecosphere is now so heavily strained that its continued stability is threatened. It is a warning that we must discover the source of this suicidal drive and master it before it destroys the environment-and ourselves.

Our assaults on the ecosystem are so powerful, so numerous, so finely interconnected, that although the damage they do is clear, it is very difficult to discover how it was done. By which weapon? In whose hand? Are we driving the ecosphere to destruction simply by our growing numbers? By our greedy accumulation of wealth? Or are the machines which we have built to gain this wealth-the magnificent technology that now feeds us out of neat packages, that clothes us in man-made fibers, that surrounds us with new chemical creations-at fault?