Predictions of humanity’s doom have been around seemingly as long as humans have existed. But the book “The Population Bomb,” by Stanford University biologist Paul R. Ehrlich and his uncredited wife Anne, was supposed to be a special case, grounded in science. Released 50 years ago and selling 2 million copies, the book horrified readers by claiming that humanity is destined for subsistence living. There would be barely enough food and other goods to sustain life, while mass starvations and civil strife would periodically cull the population.

The Ehrlichs even predicted when doomsday would arrive. According to the first edition, “In the 1970s, hundreds of millions of people will starve to death despite any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate.”

What could humanity do? According to the Ehrlichs, even bold government action couldn’t avert this fate, but it might delay the suffering. They suggested adding temporary sterilants to the public water supply, paying men to undergo permanent sterilization, and imposing hefty taxes on children’s goods and on large families in order to discourage offspring. As for impoverished third-world countries, the Ehrlichs supported cutting off food aid so that starvation would reduce those countries’ populations, as well as government programs of forced sterilization.

But as the 1970s unfolded, it became clear doomsday wasn’t descending. There were famines, but they were the products of malevolent government—wars, forced starvations, communism—not overpopulation. Meanwhile, the capitalistic West experienced ever-higher living standards and growing life expectancy. So in subsequent editions of the book, the Ehrlichs revised their timeframe: doomsday would come in the 1980s.

At the University of Maryland, a business professor named Julian Simon believed the Ehrlichs’ predictions were nonsense. Simon’s research focused on human innovation and he had great faith that the incentives of market forces would overcome the problems of scarcity. So he took to the pages of the scholarly journal Social Science Quarterly to challenge Ehrlich to a wager.

Simon proposed that Ehrlich select one or more specific raw materials that he believed would grow scarcer in the coming years, as his book predicts. Ehrlich would also set a time period in which that scarcity would become apparent. Simon and Ehrlich would compare the inflation-adjusted prices of the materials at the end of the period to the prices at the beginning. If the prices increased over time, that would show greater scarcity and Simon would pay Ehrlich the difference. But if the price decreased, that would show less scarcity and Ehrlich would pay Simon the difference. (They used inflation-adjusted prices because general inflation is the product of central banks manipulating the value of money, and is unrelated to scarcity.)

Ehrlich accepted the wager. He chose five metals—chromium, copper, nickel, tin and tungsten—and a 10-year time period, ending September 29, 1990. At the end of the period, the inflation-adjusted price of all five materials had fallen—even as the world’s population grew by almost 20 percent to 5.3 billion. Ehrlich sent Simon a check for $576.07.

What went wrong with the Ehrlichs’ prediction? Their greatest mistake is that they didn’t appreciate the power of human innovation under economic incentives. As a resource grows scarce and its price rises, there is strong incentive to find new supplies, to economize on the resource’s use, and to find substitutes for it. That’s why the prices of natural resources like oil tend to move in cycles, with a period of high prices sparking exploration and innovation, which then leads to lower prices.

None of this is to say that we shouldn’t worry about the environment. Human history offers plenty of examples of humanity’s ability to harm the world we live in. However, the fizzle of “The Population Bomb” and Ehrlich’s lost wager underscore the power of human ingenuity—including its ability to meet environmental and resource challenges. For policymakers and political activists, this tale should highlight the benefits of harnessing that power with economic incentives rather than crushing it under government dictates. And it should dampen the temptation to make further predictions of humanity’s doom on a barren, depleted earth.

Thomas A. Firey is a Maryland Public Policy Institute senior fellow and a Washington County native.