As most commonly used, the term scarcity refers to a limited supply of some material. With the rise of environmental consciousness in the 1960s, scarcity of natural resources became an important issue. Critics saw that the United States and other developed nations were using natural resources at a frightening pace. How long, they asked, could nonrenewable resources such as coal, oil, natural gas, and metals last at the rate they were being consumed?

A number of studies produced some frightening predictions. The world's oil reserves could be totally depleted in less than a century, according to some experts, and scarce metals such as silver, mercury, zinc, and cadmium might be used up even faster at then-current rates of use.

One of the most famous studies of this issue was that of the Club of Rome, conducted in the early 1970s. The Club of Rome was an international group...