Left Behind

In “The Metabolism of Cities,” the celebrated sanitary engineer Abel Wolman describes urban areas as living organisms: They guzzle water, energy, and resources and then excrete sewage, garbage, and air pollution. By Wolman’s calculations, each dweller of a hypothetical city of 1 million would be directly or indirectly responsible for 120 gallons of sewage and four pounds of refuse every day.

This was in 1965, when the U.S. population was around 189 million. The Great Lakes were already becoming fouled; the first skein of automotive smog had descended over the skies of Los Angeles. Wolman, correctly, saw trouble ahead. ”As man has come to appreciate that the earth is a closed ecological system, casual methods that once seemed acceptable for the disposal of wastes no longer seemed acceptable,” he wrote. “He has the daily evidence of his eyes and nose to tell him that his planet cannot assimilate without limit the untreated wastes of his civilization.”