If we could create Good ones, or transform our Bad cities into Good cities, not only would they stop destroying nature, they could aid in her recovery. Furthermore they could bring about a human recovery, too. Acid rain and global warming are caused for the most part by the fuel-consumption patterns of modern cities. They require a constant flow of raw resources from forests, fishing grounds, mines, rivers, aquifers, and farmlands. In payment for these, cities pump back poisons and wastes and create mountains of garbage.
Cities are also crucibles of human misery.
Half of Third World city-dwellers have no plumbing or electricity. Disease, prostitution, violent crime, and drug abuse all flourish in cities. What's more, between 1950 and 1990 the number of urbanites soared from 200 million to over two billion. And as cities expand they devour everything in their path. Three billion people are expected to live in cities by 2025.