There are those who perceive any effort to limit population growth as "population control." This is a term that chillingly evokes coercive state intervention to control individual reproductive behavior. Population control programs have rarely been implemented without exacting unacceptable ethical costs.
But there's a big difference between coercive state-led population control programs and efforts to slow rapid population growth. Population control programs target the actions of individuals. Efforts to slow the population growth rate, meanwhile, work within existing societal contexts and seek to produce voluntary change.
Population size and composition are among the key drivers of climate change. Whether there are 7 billion or 14 billion people on Earth matters on a fundamental level for the climate. But the relationship between population and planetary health is not straightforward. A child born in, say, North America will have a heavier carbon footprint than will her age-mate born in sub-Saharan Africa.
Regions with the heaviest carbon footprints are experiencing slower population growth than other regions. Many countries—including Japan and Russia, and most nations in Eastern Europe—are experiencing negative population growth. But this is not the case in sub-Saharan Africa. Between 1950 and 2000, the region’s population grew from fewer than 180 million to more than 642 million. Just since 2000, the region’s population has increased by half, to nearly 1 billion. By 2050, the population of sub-Saharan Africa is projected to more than double, to 2.1 billion—and 50 years after that, the region will be home to an estimated 4 billion people. Under that scenario, two out of every five human beings in 2100 will be sub-Saharan Africans.
Sub-Saharan Africa's carbon footprint is light. But the region's rapidly growing population has an environmental impact that is already very evident. Ecosystems such as tropical rain forests are degrading rapidly. Inefficient agricultural practices are creating undesirable land use changes. Biodiversity is diminishing. All these effects can be expected to intensify if Africa's population grows as projected.
African policy makers do care about the region’s rapid rate of population growth—but climate change is by no means the top reason why. In Africa, increased demand for basic services—without increased resources to pay for them—can stretch infrastructures beyond capacity. This makes each successive government in the region appear less effective than the regime that preceded it. Education is a good example of increasing demand for public services. UNESCO estimates that sub-Saharan Africa, to achieve universal primary and lower secondary school coverage by 2030, will require an additional 2.1 million primary school teachers and 2.5 million additional lower secondary school teachers. At the same time, demand for jobs, housing, and other necessities will also increase. Clearly, political leaders in sub-Saharan Africa face enormous challenges due to rapid population growth.
Political leaders are also concerned about population growth because they fear insecurity and instability. Extremists can find adherents more easily in a larger pool—especially in a large pool of young people whose poor education, poor employment prospects, and lack of options can leave them disenchanted.
Leaders also take an interest in population because of the potential for a so-called "demographic dividend"—that is, an improvement in a nation's economic prospects when its ratio of working-age to non–working age people increases.
So it’s no surprise that when African policy makers consider population growth, climate change is not central in their thinking. But what should be the key concern regarding the 4 billion Africans who might exist in 2100?
The issue isn't whether Africa, a continent of more than 3 billion hectares, has enough space for so many people. Even an Africa with 4 billion inhabitants would have far fewer people per unit of habitable land than India has today. Really, the key question is this: What type of people will these 4 billion Africans be? Will they be poor, sick, uneducated Africans trampling over each other to escape? Or will they be healthy, educated, productive Africans delighted to live on the continent of their birth and contributing to regional (and global) progress and development? Most of all, how can sub-Saharan Africa transform its demographic future into something manageable, development-oriented, and economically viable—while fully respecting individual reproductive choices?
African nations can change their demographic and development trajectories for the better if they vigorously pursue three key policy actions. The first is to provide universal access to family planning services, which have been shown to significantly reduce the number of children born even in poor, uneducated, and rural populations. An increase of just 15 percentage points in contraceptive prevalence is associated with a one-child reduction in the number of children born to the average woman. In sub-Saharan Africa, increasing contraceptive prevalence by 45 percentage points could reduce the total fertility rate from 4.7 to 1.7, which would bring the region’s population growth rate to below replacement levels.
The second key policy initiative involves efforts to delay marriage and childbearing. All else being equal, a population in which women begin having children at age 15 will have 25 percent more people after 60 years than a population in which women bear their first child at age 20. The longer a girl's marriage is delayed, the more opportunity she has for personal development—and the better it is for the entire country.
A third important step is to expand girls' access to education beyond the primary-school level. Women, if they receive additional education as girls, have fewer children; this has been demonstrated consistently. Improved education also provides women better opportunities for earning an income—precisely what developing countries need in order to achieve economic development. Implementing these three policy initiatives would lead to more sustainable, more durable, and (most importantly) quicker reductions in the population growth rate than any coercive government action would achieve.
The prospect of 4 billion Africans by 2100 can be cause for concern—or it could inspire commitments to invest in educational opportunities for girls, greater access to family planning, and delayed marriage. These steps would be transformative for the continent. They would generate development and promote economic growth in addition to reducing the demographic burden that contributes to climate change. But while African efforts to slow population growth will contribute to planetary health, one mustn't forget that the greatest culprits in the race to destroy the planet are the countries with the heaviest carbon footprints. Global initiatives and investment are required to support African countries as they work to achieve a demographic dividend—but these must be matched by appropriate, complementary efforts to mitigate the environmental damage wrought by countries expecting zero or even negative population growth.