- Overpopulation has been blamed for everything from climate change to poverty.
- Historically, there have been two theories for overpopulation, and evidence for each is scant to nonexistent.
- The real problems — global socioeconomic inequality and environmental degradation — are not attributable to population growth.
The world’s human population grew dramatically in the twentieth century, from 1.6 billion in 1900 to 6.1 billion in 2000. As it grew, population began to take the blame for some of the world’s most pressing and intractable problems, from poverty to geopolitical instability to climate change. But how did the fact of population growth become the problem of overpopulation, and how did framing the world’s major concerns as “population problems” limit the range of possible solutions?
My new book, Building the Population Bomb (Oxford University Press, 2021), answers these questions by tracing the development of two scientific theories of overpopulation, one environmental and the other economic, across the 20th century. It elucidates the sociotechnical networks that gave these theories the power to shape the world’s population by informing and legitimating governmental and nongovernmental interventions into the intimate lives of some of the world’s most vulnerable people.
The birth of American eugenics
The two theories of overpopulation grew out of competing scientific approaches to population that appeared in the United States in the 1920s, at the height of the eugenics movement and in the midst of intense debates about the value of immigration. Biologists focused on aggregate growth rates, which they read through a Malthusian lens to predict imminent overpopulation. They proposed immigration restriction and a eugenic birth control program. Statisticians and social scientists focused on age-specific fertility and mortality rates, which they read through a mercantilist lens to predict a disastrous slowing of population growth. They opposed immigration restriction but still favored eugenics; whether the U.S. population was growing too quickly or too slowly, all scientists agreed on the importance of promoting large families among the “right” people and small families among the “wrong” people.
The American eugenics movement also began to divide around the end of the 1920s. Older eugenicists, who aligned with the biological approach to population, continued to view Southern and Eastern Europeans — and anyone who wasn’t white — as the “wrong” people and continued to favor direct government intervention into reproduction. Younger eugenicists, who aligned with the statistical and social scientific approach to population, distanced themselves from overt racism, which had become the hallmark of fascist eugenics programs in Europe. These younger eugenicists also eschewed state intervention into reproduction, instead favoring the creation of financial incentives and a social climate in which the “right” people would have large families and the “wrong” people would have small families, all under the guise of reproductive freedom. They called this program “family planning.”
In the 1930s, the American Eugenics Society became the home of this new brand of eugenics. Its leaders saw the burgeoning science of population as a key ally for their agenda and directed funding toward the statisticians and social scientists, supporting their mercantilist approach to population. These were the scientists who became known as demographers and to whom the New Deal state looked for assistance in administering its social and economic programs.
The Malthusian biologists were sidelined in the establishment of demography, but supporters of the older version of eugenics — including businessmen, diplomats, and natural scientists — kept Malthusianism alive in the American popular consciousness. After World War II, Malthusians and demographers both turned their attention to the global horizon, where it became clear that population was poised for rapid growth. North America, Western Europe, and Oceania were experiencing a postwar “baby boom.” More worrisome to American observers, however, was the fact that death rates were falling rapidly in Asia, Latin America, and the Caribbean, while birth rates remained high. Malthusians compared the aggregate world population to the planet’s carrying capacity, warning that population growth anywhere would quickly deplete the Earth’s natural resources, stimulating the spread of global communism and ushering in nuclear war.
Demographers focused on the national level, comparing population growth rates to rates of economic growth. For them, overpopulation was a problem only in the Global South, where they warned that rapid population growth would prevent economic development. Empirical evidence for the demographic theory of overpopulation was scant; empirical evidence for the Malthusian theory of overpopulation was nonexistent. Nonetheless, the two theories supported one another to produce intense anxiety about population growth among the American public, the U.S. government, and the leaders of developing countries worldwide.
“Population bomb”: Wrong diagnosis, wrong solution
Demographers and their sponsors extended the interwar eugenic project of family planning to developing countries, where they aimed to create a climate in which birth control was so widely available and socially acceptable that it would be almost harder not to use it. This aim was facilitated by the IUD, the development and manufacture of which was bankrolled by the Population Council, a U.S.-based nongovernmental organization that also funded demographic research in the Global South and the training of students from developing countries in demography graduate programs in the U.S.
Malthusians initially saw family planning as a solution to their population problem as well. Working through such organizations as the Population Reference Bureau and the Population Crisis Committee, Malthusians appealed to the American public and U.S. policymakers to support the work of the Population Council and other nongovernmental organizations involved in family planning. As a result, the U.S. Agency for International Development began to earmark funds for this purpose in 1965. By the end of the 1960s, however, Malthusians were complaining that family planning was not doing enough to slow population growth. Instead, they recommended that governments impose legal limits on childbearing. They received intellectual support from a younger generation of biologists, most notably Paul Ehrlich, who published The Population Bomb in 1968, and Garrett Hardin, who coined the term “tragedy of the commons,” also in 1968. Demographers and their supporters described the Malthusian approach as coercive, so anything short of legal limits on childbearing, such as financial incentives to accept IUDs, passed as non-coercive.
The two theories of overpopulation, coming from the U.S., clashed on a global stage at the 1974 UN World Population Conference, where leaders of countries in the Global South rejected all efforts to limit population growth as imperialist. Intellectuals and heads of state from Asia, Africa, and Latin America blamed poverty and environmental degradation on the industrial practices of countries in the Global North. Declaring that “development is the best contraceptive,” they demanded the implementation of the New International Economic Order that had been laid out by the UN Conference on Trade and Development in 1972. Nearly 50 years later, however, experts in the U.S. continue to attribute poverty in the Global South and climate change worldwide to population growth. Economists recommend that developing countries reduce their birth rates in order to reap the “demographic dividend,” while natural scientists and bioethicists recommend that governments place limits on childbearing to stave off climate change.
As was the case in the mid-20th century, natural scientists and social scientists disagree over what constitutes overpopulation and what should be done about it. The tension between these two theories of overpopulation, however, promotes the popular belief that the world’s human population is growing too quickly and that something needs to be done about it. Together, they present population as a smokescreen to obscure the more proximate causes of the problems they attribute to population growth, namely, global socioeconomic inequality and environmental degradation. By focusing debate on how to most effectively and equitably slow population growth — legal limits on childbearing or voluntary family planning — proponents of overpopulation elide more direct regulatory and redistributive solutions to the world’s most pressing concerns. Framing these issues as “population problems” gets the U.S. and its corporations off the hook, at the expense of the most vulnerable members of the world’s population and the planet itself.