The United Nations announced this week that the world population is expected to reach 10 billion by the end of the century—and then just keep on growing (more details in the pdf). That's a big increase from the previous estimate of a peak of 9 billion that would then stabilize or shrink.
Science magazine has a helpful Q&A that explains where these 1 billion previously unanticipated people of the future come from. Some of it is good news: fewer people are dying from AIDS than expected. Some less so: many family planning programs were abandoned in the past 20 years.
The new report is awash in data; it can be broken down by fertility and mortality models, age range and country. Like anyone who uses Google Earth for the first time, I immediately looked for home: the U.S. population should reach almost half a billion by 2099. That's a lot of people, but the new numbers don't really change the predictions for U.S. demographics in 2050 that Joel Kotkin made in Smithsonian magazine last year. That story was pretty optimistic: growth is better than decline; technology will make life better; immigrants will revitalize American culture. Here's a taste:
Political prognosticators say China and India pose the greatest challenges to American predominance. But China, like Russia, lacks the basic environmental protections, reliable legal structures, favorable demographics and social resilience of the United States. India, for its part, still has an overwhelmingly impoverished population and suffers from ethnic, religious and regional divisions. The vast majority of the Indian population remains semiliterate and lives in poor rural villages. The United States still produces far more engineers per capita than India or China.
One of the least anticipated developments in the nation’s 21st-century geography will be the resurgence of the region often dismissed by coastal dwellers as “flyover country.” For the better part of the 20th century, rural and small-town communities declined in percentage of population and in economic importance. In 1940, 43 percent of Americans lived in rural areas; today it’s less than 20 percent. But population and cost pressures are destined to resurrect the hinterlands. The Internet has broken the traditional isolation of rural communities, and as mass communication improves, the migration of technology companies, business services and manufacturing firms to the heartland is likely to accelerate.
In discussing population growth, there's a perpetual tension between economists (who consider an ever-expanding economy and workforce the greatest good) on one side and geologists, population biologists and environmentalists on the other (who point out that resources are limited, and in some cases we're reaching the limit). The most immediate challenge posed by an increasing population, even today and certainly by mid-century or beyond, will be feeding all of these people.