In population circles, it's known simply as The Bet. Stanford University biologist Paul ("Population Bomb") Ehrlich had wagered University of Maryland economist Julian Simon in 1980 that the price of five basic metals would rise. The stakes: $1,000. Ten years and 800 million people later, Ehrlich lost: despite his prediction that a rising population would increase demand for and prices of resources, the metals all cost less.
Behind the scenes at the Cairo conference, sanguine economists are facing off against doomsaying biologists once again, and this time the stakes are considerably higher than $1,000. Many biologists, who see the world as a finite system able to support finite numbers, warn that the 10 billion people who the United Nations projects will live on the planet in 2050 will strain water, soil and other resources to the breaking point, causing horrific environmental damage, widespread hunger and global misery. Many economists counter that free markets will keep supplies of even scarce commodities in line with demand and will stimulate the search for substitutes, much as fiber optics are now replacing copper wires in communications. And science, they believe, will always come through with technological fixes like the green revolution. Not surprisingly, the clashing world views produce starkly different views of the future:
Economists argue that scarcity will drive up prices and induce more food production. But in Japan, says Brown, the price of rice is six times the world average -- and biology has trumped economics: the rice has stopped responding any further to fertilizer and other high-tech practices. Yields have been flat since 1985. Round 1: doomsayers.
Which is not to say, the more the merrier. Poor countries might well have done better with slower population growth. When East Asian tigers like South Korea instituted family-planning programs in the 1960s, they were able to invest in education and health care and reap huge economic windfalls. True, studies show no ill effects of population on poverty or development through the 1970s. But in the 1980s, rising Third World populations began to cause "less savings and investment, and education was [hurt]," says Duke University economist Allen Kelley. "There is a more-than-even chance that population is now adversely affecting development. I cannot rule out that we are now approaching biological limits." Round 2: optimists -- but maybe not for long.
Since the jury is still out on the effects of rising population, prudence might suggest erring on the side of caution. That's especially true since "the consequences of being wrong [about the effects of population growth] are so catastrophic," says Steven Sinding of the Rockefeller Foundation. Indeed, optimists have tripped up before. In 1982 the Unit-ed Nations estimated that Sudan could feed 260 million people; today the 27 million Sudanese suffer persistent famine due to political chaos. Most important, although population growth produces a young and healthy labor force, sheer numbers are no loner an engine of prosperity: training and education are. And poor countries with rapidly rising populations are finding it ever harder to train their people. As human resources become the route to prosperity, the ghost of Malthus may yet begin to stir.