Fears of population explosion are shrinking

Remember the population bomb, the fertility explosion set to devour the world's food and suck up or pollute all its air and water? Its fuse has by no means been plucked. But over the last three decades, much of its Malthusian detonation power has leaked out.

Birthrates in developed countries from Italy to Korea have sunk below the levels needed for their populations to replace themselves; the typical age of marriage and pregnancy has risen, and the use of birth control has soared beyond the dreams of Margaret Sanger and the nightmares of the Vatican.

The threat is now more regional than global, explosive only in places like India and Pakistan. Ever since 1968, when the U.N. Population Division predicted that the world population, now 6.3 billion, would grow to at least 12 billion by 2050, the agency has regularly revised its estimates downward. Now it expects population to plateau at 9 billion.

Where did those billions go? Millions of babies have died, a fraction of them from AIDS, far more from malaria, diarrhea, pneumonia, even measles. More millions have been aborted, either to avoid birth or, as in China and India, to avoid giving birth to a girl. (Cheap ultrasound technology has in the last decade made it easy to determine a child's sex.)

But even AIDS and abortion are drops in the demographic bucket. The real missing billions are the babies who were simply never conceived. They weren't conceived because their would-be elder brothers and sisters survived or because women's lives improved.

In the rich West, Mom went to college and decided that putting three children through graduate school would be unaffordable. In the poor Eastern or Southern parts of the globe, Mom found a sweatshop job and didn't need a fourth or fifth child to fetch firewood.

"On a farm, children help with the pigs or chickens," explained Joseph Chamie, director of the U.N. population division. Nearly half the world's people live in cities now, he said, "and when you move to a city, children are not as helpful."

Beyond that, simple public health measures like dams for clean water, vitamins for pregnant women, hand-washing for midwives, oral rehydration salts for babies, vaccines for youngsters and antibiotics for all helped double world life expectancy in the 20th century, to 60 years from 30.

More surviving children means less incentive to give birth as often. As late as 1970, the world's median fertility level was 5.4 births per woman; in 2000, it was 2.9. Barring war, famine, epidemic or disaster, a country needs a birthrate of 2.1 children per woman to hold steady.