Pencil in October 31, 2011 on your calendar. It’s not just the one day of the year you get to dress like Edward Cullen without everyone thinking there’s something deeply wrong with you. According to the United Nations Population Division (UNPD)—the demographers who rule over all demographers—that’s the day when the 7 billionth person on the planet will be born.
But will population growth be a trick for the planet—or a treat? That still remains to be seen. The new UNDP numbers (PDF), released earlier today, project that global population could reach 9.3 billion by mid-century, and rise to 10.1 billion by 2100. That’s a revision upwards from earlier numbers, which had projected population to level off at about 9 billion by 2050. The difference? Unexpectedly high and continued population growth in Africa, where the UNDP now predicts population could rise from 1 billion today to an almost unimaginable 3.6 billion by the end of the century, at the highest estimates. Nigeria, already Africa’s most populous nation at 162 million, could grow to 730 million by 2100, while Malawi—a country smaller than Pennsylvania—could grow from 15 million to 129 million. Given the difficulties Africa finds today in feeding and supporting itself, more than tripling of the current population could cause havoc and misery—and that’s without even counting the impact of global warming, which could further stress agriculture and water, while worsening infectious disease. As John Bongaarts, a demographer at the Population Council, told the New York Times:
Every billion more people makes life more difficult for everybody — it’s as simple as that. Is it the end of the world? No. Can we feed 10 billion people? Probably. But we obviously would be better off with a smaller population.
Even as Africa continues to multiply, other low-fertility regions like Europe, Russia and Japan will actually decline in population, and age rapidly. (42% of the world’s population currently lives in areas where fertility is actually below replacement rate.) China—thanks in part to its one-child policy—will grow slowly to 1.4 billion (up from about 1.3 billion now) before eventually falling below 1 billion, while India will eventually pass it as the world’s most populous nation.
All in all, it’s looking to be a very crowded future—and since population is the great multiplier of all environmental ills, that would seem to be bad news for the planet. But any prediction made 90 years into the future should be taken with a whole mine’s worth of salt—and that’s especially true for population projections, as any reputable demographer will tell you. The predictions are made based on fertility data—how many children each woman plans to have—and the projections are incredibly sensitive to any changes. Increase fertility by just half a woman per child, and global population could rise to 16 billion by 2100.
Obviously, that’s not too likely to happen. But the most recent projections were revised upward today largely because fertility rates in much of the world—and especially Africa—have remained higher than demographers had expected. In high-fertility countries, fertility is still at nearly 5 children per woman, compared 1.6 per woman in low-fertility nations. The good news is that fertility can be controlled—and not in a controlling way. As countries get better off, fertility rates tend to drop, a phenomenon known as the fertility transition that’s been seen pretty much everywhere. But that requires the availability of contraception—and importantly, empowering women to actually use contraception. A quick and revealing stat: while three-quarters of married American women use a modern contraceptive, only a quarter of women in East Africa do, one in 10 in West Africa and just 7% on Central Africa.
Women in these countries need help from overseas, but aid for family planning—at $238 million in 2009—is far too low, and budget problems and social controversies mean the U.S. won’t be able to make up much more. That’s a shame—actually, it’s a tragedy. As Robert Engelman—a vice-president with the Worldwatch Institute—writes in an excellent journal article, unsustainable population growth isn’t inevitable, and population control doesn’t require authoritarian means. The key is education:
More than 40 percent of all pregnancies are unintended, with higher proportions in developed than in developing countries.
As these figures suggest, it might be possible to end and then reverse human population growth through a strategy aimed at elevating women’s status and increasing access to contraceptive services, so that essentially all births result from intended pregnancies. Preliminary calculations based on conservative assumptions suggest that global fertility would immediately move slightly below replacement levels, putting world population on a path toward an early peak followed by gradual decline. The success of such a strategy would have many other benefits, such as reducing disability and deaths among mothers and their children and freeing more women to earn money and participate actively in social affairs.
There are very few truly win-win policies out there, but female education and access to contraception is one of them. Demography is destiny, it’s true—but we can control our demography.
More from TIME on population: