The lesson of Easter Island. (Greenwatch)

Population Action International (PAI) is an American non-governmental organization whose work is inspired by a historical event. When a group of Polynesian voyagers arrived on Easter Island in the fifth or sixth century A.D., they found a plentiful supply of natural resources and created a unique civilization, now famous for its enormous and mysterious stone statues. But studies of fossilized pollens have shown that as the population grew, the lush green forest diminished, leading to a fatal erosion of the fertile soil and disappearance of the island's wildlife. When a Dutch traveller set foot on the island in 1722, he observed that it was completely barren. Deprived of natural resources, …