"If the crisis that now confronts us is even more urgent than those of the early years of the century-and I believe it is this is because of wholly new factors peculiar to our own time. These are, first of all, the phenomenal growth of the human population, threatening to over-run its own environment in a way that can bring only deep concern to thoughtful students of population problems. The second factor is a corollary of the first: that as people and their demands increase, there is a smaller share of the earth's resources for each of us to use and enjoy. There is less clean water, less uncontaminated air; there are fewer forests, fewer unspoiled wilderness areas. The third reason is the introduction of new and dangerous contaminants into soil, water, air, and the bodies of plants and animals as our new technology spreads its poisons and its discarded wastes over the land."