It’s a Small World

Sometime around Halloween, the United Nations will celebrate the birth of the world’s 7th billion baby. As U.N. Secretary General Ban Ki-moon told world leaders in New York last month, the 7th billion baby will most likely be poor and will inhabit an earth buffeted by the ravages of global warming, desertification, and dwindling food shortages.

Sounds swell. Given this kind of apocalyptic rhetoric, it’s no surprise that much of the media’s focus has been on the strain of an over-populated planet, one where more than 79 million people are added each year to the human family, overwhelming already overcrowded cities, fighting it out over a dwindling pool of natural resources.

But what if the world’s population actually shrank?

While global population has tripled since the U.N.’s creation in 1945, global fertility rates over the past 100 years have steadily declined, from a high of 6 children per family at the dawn of the 20th century, to about 5 in 1950, to 2.5 today. The United Nations expects to reach a break-even replacement rate of about 2.1 children per family after 2100.

The United Nations has produced a range of scenarios showing population growing to nearly 10 billion over the next century — or even as high as nearly 27 billion, if the current rate of population growth continues through the next century (needless to say, an outcome that many demographers see as unsustainable).

More likely, according to U.N. statisticians, is that population will gradually rise to 8 billion in 2025, 9 billion in 2043, hit 10.1 billion by century’s end, and then stabilize. The so-called "medium variant" projection assumes that countries with high fertility rates like Niger, with a rate of 7.37 babies per woman, and those with low fertility rates, like South Korea, where women have an average of only 1.2 children, will ultimately converge.

That assumption, like most others, is pretty much a guess, and doesn’t take into account potential cataclysmic events, like an asteroid hurtling into earth or perhaps a more plausible scenario in which mass numbers of people die by infectious diseases. The HIV/AIDS epidemic temporarily slowed the rates of population growth in Africa, preventing the African continent from surpassing the combined population of Europe and the Americas by 2025.

"Demography is not destiny. In some ways the most implausible assumption is the idea that the entire world is going to start having 2.1 children. There is no reason to believe that is going to happen," said Matthew Connelly, a history professor at Columbia University and author of Fatal Misconception: The Struggle to Control World Population. "It wouldn’t surprise me if we have more surprises ahead."

Indeed, predicting population growth or contraction is pretty much a losers’ game.

Demographers have missed some of the most important demographic shifts of the past century, including the first decline in the U.S fertility rate during the Great Depression, the post-World War II "baby boom," and the explosion of human migration in the 1970s.

Joel E. Cohen, a scholar at Rockefeller University who studies population trends, agreed that demographers have been poor predictors. "I view the projections beyond 2050 as ‘what if’ scenarios. I don’t view them as statement about what will happen," he said. "We did not predict the baby boom and we did not predict the baby bust that followed. Our capacity to predict even for people who are alive is limited," he said.

For example, the precipitous drop in Iran’s fertility rate, from 6.9 in 1960 to 1.6 today, caught the world by surprise, particularly since most of the decline took place after the Islamic Revolution. "Nobody in 1980 could have predicted that Iran’s total fertility rate would be well below the replacement rate today."

Cohen also noted that dire predictions that declining populations will hinder economic growth fly in the face of economic reality.

Many of the world’s richest countries, which have experienced declines in fertility rates, have prospered, while many of the world’s poorest countries are struggling economically.  "Take two of the most prosperous countries, Germany and Japan: they have a declining population and for the time being they are economic dynamos. There is no necessary link between prosperity and population growth."

But even under the U.N.’s most-likely scenario, which predicts population will top 10 billion by century’s end, scores of countries will contract, placing enormous pressure on their governments to ensure economic progress and social stability — with a diminishing work force and market, and a shrinking supply of young people to care for an increasingly elderly population. Already, at least 80 countries have fallen below the 2.1 children replacement level, including Germany, Italy, Japan, Russia, South Korea, and Spain, where fertility rates have dropped to 1.5 children per woman, or below.

To reflect the uncertainty, the U.N. also publishes variations on its projection for future global fertility rate. Two U.N. models assume population will approach either a 2.5 or a 1.5 fertility rate — the U.N.’s low and high variants — which will push the population up to 15.8 billion or down to 6.2 billion by 2100, the latter being a decline of about 800 million people.

A smaller population could ease the pressure on Mother Nature, ensuring a more sustainable exploitation of the environment. But the future for these shrinking states — defined by a combination of large numbers of retired elderly and small number of working youth — could be grim, particularly if they fail to absorb young migrants.

Europe (including Russia) which reached a population peak of 731 million in 2005 is projected to see its first decline in population in history, dropping to 664 million by the middle of the century. U.N. estimates project that Russia’s population, now 143 million, could decline by nearly 35 million, according to the most likely projection — if the current rate of decline keeps pace. The decline has prompted some European countries, including France and Macedonia, to provide economic incentives, including cash or subsidized child care, to encourage mothers to have more children.

China and India, the world’s two most populous countries, have sought to curb population growth during the past four decades through a series of often draconian mandatory measures, including China’s one-child policy, and large-scale sterilization programs. But the cost has been high in human terms, particularly in China, where20 percent of boys born in the 1990s are expected to be unable to find a mate, according to Connelly.

China’s youth bulge will likely be followed by an increasingly old population, placing greater strains on China’s new generation to care for numerous grandparents. By mid century, 30 percent of China’s population will be over 65 years old. And they will be in far poorer health then their counterparts in the West, given the soaring rates of cigarette smoking and high rates of lead poisoning and other environmental ills.

Connelly says he suspects that the global population will stop growing around the middle of this century, and that China and India may serve as models of how countries work in the future to control population growth. "I’m afraid of a return to more coercive measures," he said.

The United States has largely avoided the fate of many other developing countries on the back of its large population of immigrants. Despite its demographic benefits, immigration has come under increasing political attack in the United States, which announced it had deported more than 400,000 foreigners during the past year, more than at any time in U.S. history.

But is this really something Washington should be trumpeting?

"We don’t have a model of a country with declining population experiencing economic growth," says Joseph Chamie, the former director of the U.N. Population Division and currently research director at the Center for Migration Studies, who says world economic growth has depended on a booming population since the Industrial Revolution.

Chamie contrasted the fate of two American cities: Detroit, which has seen population drop by 25 percent over the past decade, has been brought to its knees. New York City, which has seen an increase of 400,000 people over the same period, has prospered. It’s growth driven largely by immigration.

"If you have declining population it has benefits: a smaller environmental footprint, less consumption, but you will also have fewer workers for every retiree. It can become a very large financial burden" on the young, he said. "We don’t know exactly how to proceed if the population starts to decline as we see in Russia, Japan and elsewhere….We are now in uncharted waters."