Eight billion corresponds to the UN’s lowest projection for 2050. In that optimistic scenario, Bangladesh has a fertility rate of 1.35 in 2050, but it still has 25 million more people than it does today. Rwanda’s fertility rate also falls below the replacement level, but its population still rises to well over twice what it was before the genocide. If that’s the optimistic scenario, one might argue, the future is indeed bleak. But one can also draw a different conclusion—that fixating on population numbers is not the best way to confront the future. People packed into slums need help, but the problem that needs solving is poverty and lack of infrastructure, not overpopulation. Giving every woman access to family planning services is a good idea—“the one strategy that can make the biggest difference to women’s lives,” Chandra calls it. But the most aggressive population control program imaginable will not save Bangladesh from sea level rise, Rwanda from another genocide, or all of us from our enormous environmental problems. Global warming is a good example. Carbon emissions from fossil fuels are growing fastest in China, thanks to its prolonged economic boom, but fertility there is already below replacement; not much more can be done to control population. Where population is growing fastest, in sub-Saharan Africa, emissions per person are only a few percent of what they are in the U.S.—so population control would have little effect on climate. Brian O’Neill of the National Center for Atmospheric Research has calculated that if the population were to reach 7.4 billion in 2050 instead of 8.9 billion, it would reduce emissions by 15 percent. “Those who say the whole problem is population are wrong,” Joel Cohen says. “It’s not even the dominant factor.” To stop global warming we’ll have to switch from fossil fuels to alternative energy—regardless of how big the population gets. The number of people does matter, of course. But how people consume resources matters a lot more. Some of us leave much bigger footprints than others. The central challenge for the future of people and the planet is how to raise more of us out of poverty—the slum dwellers in Delhi, the subsistence farmers in Rwanda—while reducing the impact each of us has on the planet. The World Bank has predicted that by 2030 more than a billion people in the developing world will belong to the “global middle class,” up from just 400 million in 2005. That’s a good thing. But it will be a hard thing for the planet if those people are eating meat and driving gasoline-powered cars at the same rate as Americans now do. It’s too late to keep the new middle class of 2030 from being born; it’s not too late to change how they and the rest of us will produce and consume food and energy. “Eating less meat seems more reasonable to me than saying, ‘Have fewer children!’ ” Le Bras says.
