Hello and happy Seven Billion Day from human #2,873,665,681! Or maybe I’m really #2,874,426,148. It depends on which of the web-based population counters I enter my birth date in. That small ambiguity in the number of humans there were many years ago (guess how many) actually understates the uncertainty about how many there are today. According to the UN, which does its level best to count us all every two years, including those of us who live in countries without birth records or censuses, the uncertainty is at least 1 percent. Human #7,000,000,000 may be born today—or maybe that milestone was six months ago or maybe it’s still six months ahead. The UN chose Halloween as a “symbolic date.” It chose aptly: Population has been the monster knocking at our door for a long time.
A week ago, at a gathering of environmental journalists in Miami, I heard a noted expert on penguins (which face some tough challenges in a warming world) exclaim in frustration that no one was talking about the real problem: the number of humans. Since I started reporting the first article in National Geographic’s year-long series on Seven Billion, I’ve heard this odd complaint a lot—often with the implication that people in the press and in public life are just too darn chicken or politically correct to talk about global population.
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Perhaps the flurry of coverage occasioned by the 7 billion milestone will quiet that complaint a bit. Much of the coverage has been alarmed. Last spring, when the UN gave this Halloween a new meaning, it also released its latest long-term projections—and they sounded substantially scarier than the ones from just two years earlier. Instead of leveling off somewhere above 9 billion in the second half of this century, UN demographers said, global population would keep on rising past 10 billion in 2100.
The uncertainty in those numbers is much, much larger than 1 percent. Humans are not atomic particles obeying only the laws of physics. Demographers don’t have a scientific theory that would allow them to predict the childbearing choices of women today, much less those of potential mothers in the year 2050—most of whom have not yet been born. The UN’s higher numbers mostly reflect the fear that fertility in many African countries, such as the ones Robert Draper wrote about in our November issue, will not fall nearly as fast as it has fallen in the rest of the world.
In one way, though, demographic uncertainty is like the uncertainty principle in particle physics. As UN demographers well know, their very measurements can influence the system they are measuring. If the UN’s alarming forecast leads to greater international support for education and family planning, say, in African countries south of the Sahara, that will be a good thing—because it will improve people’s lives in those places.
But as I argued in the article last January, the biggest environment problem we face globally is not population growth. It’s the way humans get and spend energy—not in the poor countries where population is still rising rapidly, but in the rich countries where it is not. The fact that we talk about population growth so much, it seems to me—and not so little—is at least in part because it lets us rich folk off the hook. It’s a way of not facing the monsters inside.
For more on population, including photos and videos, check out the special year-long series on population from National Geographic magazine and the new “7 Billion: How your world will change” app for iPad, available from the App Store. (iTunes link: http://on.natgeo.com/q301cY).