Those who do consider population to be a key to the problem typically say little about which policies would spare the planet many more billions of people. Should we restructure tax rates to favor small families? Propagandize the benefits of small families for the planet? Reward family-planning workers for clients they have sterilized? Each of those steps alone or in combination might help bend birthrates downward for a time, but none has proved to affect demographic trends over the long term or, critically, to gain and keep public support. When the government of India rewarded health workers for meeting sterilization quotas in 1976, the zeal of some of them for wielding scalpels regardless of their patients’ wishes contributed to the downfall of Indira Gandhi’s government in 1977.
And how can we reduce consumption? Ideas such as cap-and-trade plans for limiting greenhouse gas emissions and allowing companies to trade emission rights are based on the same principle: raise the price of what harms the environment to reduce consumption of it. Beyond the consumption cuts, however, such schemes don’t have much to recommend them. Governments can also eliminate subsidies of polluting behavior, an approach that is more palatable—except to the often powerful interests that benefit from the subsidies. Or governments can subsidize low consumption through tax deductions and credits, but the funds to do so on the needed scale will likely be increasingly scarce.
The Zen of Population
Mostly ignored in the environmental debates about population and consumption is that nearly all the world’s nations agreed to an altogether different approach to the problem of growth 15 years ago, one that bases positive demographic outcomes on decisions individuals make in their own self-interest. (If only something comparable could be imagined to shrink consumption.) The strategy that 179 nations signed onto at a U.N. conference in Cairo in 1994 was: forget population control and instead help every woman bear a child in good health when she wants one.
That approach, which powerfully supports reproductive liberty, might sound counterintuitive for shrinking population growth, like handing a teenager the keys to the family car without so much as a lecture. But the evidence suggests that what women want—and have always wanted—is not so much to have more children as to have more for a smaller number of children they can reliably raise to healthy adulthood. Women left to their own devices, contraceptive or otherwise, would collectively “control” population while acting on their own intentions.
More than 200 million women in developing countries are sexually active without effective modern contraception even though they do not want to be pregnant anytime soon, according to the Guttmacher Institute, a reproductive health research group. By the best estimates, some 80 million pregnancies around the world are unintended. Although the numbers aren’t strictly comparable—many unplanned pregnancies end in abortion—the unintended pregnancies exceed the 78 million by which world population grows every year.
In the U.S., which is well informed and spends nearly 20 cents per dollar of economic activity on health care, nearly one out of every two pregnancies is unintended. That proportion has not changed much for decades. In every nation, rich and poor, in which a choice of contraceptives is available and is backed up by reasonably accessible safe abortion for when contraception fails, women have two or fewer children. Furthermore, educating girls reduces birthrates. Worldwide, according to a calculation provided for this article by demographers at the International Institute for Applied Systems Analysis in Austria, women with no schooling have an average of 4.5 children, whereas those with a few years of primary school have just three. Women who complete one or two years of secondary school have an average of 1.9 children apiece—a figure that over time leads to a decreasing population. With one or two years of college, the average childbearing rate falls even further, to 1.7. And when women enter the workforce, start businesses, inherit assets and otherwise interact with men on an equal footing, their desire for more than a couple of children fades even more dramatically.