“It is only within the moment of time represented by the twentieth century that one species – man – has acquired significant power to alter the nature of his world, and it is only within the past twenty-five years that his power has achieved such magnitude that it endangers the whole earth and its life. The most alarming of all man’s assaults upon the environment is the contamination of the air, earth, rivers, and seas with dangerous, and even lethal, materials.”
