Our planet is expected to have 11.2 billion people in 2100, according to the United Nations’ just-released revision of the medium world population projections. With a 2015 population of 7.3 billion, this represents an increase of 3.9 billion over the remainder of this century. The projected expansion of human numbers is very unevenly spread around the world, with declines in Europe and East Asia and modest further growth in South and West Asia and in North and South America. In contrast, sub-Saharan Africa is expected to continue expanding rapidly with its population quadrupling from 0.96 billion to 3.93 billion between 2015 and 2100.
The bulk of future world population growth will be in this continent.
The new projection for the world is the highest-ever made by the UN. In fact, it is 2.1 billion higher than the UN projection published in 2004, which expected a world population of just 9.1 billion in 2100. A revision of this magnitude in such a short time is unprecedented. Also surprising, this upward revision is largely confined to one area of the world — sub-Saharan Africa — where the projection for 2100 increased from 1.9 billion to 3.9 billion inhabitants. Instead of expecting one billion more Africans, according to the 2004 projection, the UN now expects three billion more by 2100.
The UN continuously monitors demographic trends in countries around the world and regularly updates its projections to ensure they are consistent with the most recent information. There is one obvious and welcome reason for the upward revision for sub-Saharan Africa since 2004: the success in conquering the AIDS epidemic over the past decade. Large investments in treatment and prevention programs halted the expansion of the epidemic. Reinvigorated efforts to reduce infant and child mortality (e.g., through vaccination programs) also saved many lives.
Another, but less well-known, cause of the revision is the slower-than-expected decline in birth rates in sub-Saharan Africa over the past two decades. Until the late 1990s, conventional wisdom expected Africa’s fertility to follow the path of Asian and Latin American countries in the 1960s and 1970s, which saw fairly rapid fertility declines in particular when women gained access to schooling and to contraceptive methods. But in most of Africa, family planning programs have been neglected, and fertility declines have occurred later and at a slower pace than in other continents. In a number of countries in Africa, fertility rates have actually stalled after an initial decline.
Adding three billion people to the world’s poorest region in the next 85 years will hamper development and may lead to a continent in chaos. When countries experience very rapid population growth, economies struggle to absorb large numbers of new job seekers who compete for limited jobs, leading to low wages, unemployment and inequality. Schools and health clinics become overwhelmed and low-quality services deteriorate further. Governments are not able to keep up with the construction of infrastructure such as roads, bridges, water supplies, sewers and electricity systems.
Demand for food soars, putting pressure on marginal agricultural resources and imports of food rise. Explosive growth of urban areas largely happens in the form of slums. Frustrated unemployed young males can turn to crime and fringe political groups, creating unrest and increasing violence. Moreover, the adverse impact of massive population growth will not be confined to the continent as its greenhouse gas emissions rise and the expanding flow of migrants to other continents becomes increasingly difficult to manage.
What can be done? A straightforward and highly desirable solution exists: invest in voluntary family-planning programs. These programs allow women and couples to achieve their desired family size and avoid unintended pregnancies. As a result, these programs play a key role in reducing poverty, advancing rights and improving women’s and children’s health. They are one of the most cost-effective health and development investments available to governments.
According to a UN study, “for every dollar spent in family planning, between two and six dollars can be saved in interventions aimed at achieving other development goals,” and other studies estimate even higher returns. The largest benefits are seen in education and health sectors, with significant additional savings in infrastructure construction.
The rationale for these programs lies in the substantial unsatisfied demand for contraception in sub-Saharan Africa and throughout the developing world. When interviewed about their reproductive preferences, large proportions of women report that they do not want to become pregnant. Some of these women want no more children because they have already achieved their desired family size, while others want to wait before having the next pregnancy. Yet a large proportion of these women (more than half in some countries) are not practicing effective contraception and are therefore at risk of pregnancy.
As a result, unintended pregnancies are common. According to the Guttmacher Institute, more than one-third of pregnancies are unintended in sub-Saharan Africa. Voluntary family planning programs reduce unplanned pregnancies by providing access to and information about contraception and by reducing socioeconomic obstacles to use.
Some African governments are making progress, convinced that a greater investment in high-quality family planning programs is needed and would be acceptable and effective in improving prospects for development.
Ethiopia and Rwanda are two examples; as family planning programs have been prioritized, women have begun using them more and fertility decline has followed, as have improvements in other health and development indicators. But in a majority of African countries, including Nigeria, the Democratic Republic of the Congo and those in most of the Sahel region, family planning is still given low priority, and government leaders are reluctant to talk about contraception and the benefits of smaller families.
The future trajectory of population is highly sensitive to minor changes in the fertility trend. As a result, any program-induced fertility decline can have a large impact on population growth. This impact can be estimated by a comparison of published variants of the UN population projections for sub-Saharan Africa. While the standard (medium variant) projection for sub-Saharan Africa expects 3.96 billion in 2100, the corresponding UN low variant projection (based on reducing fertility by a half birth during the projection) leads to a population of only 2.60 billion in 2100, a reduction of 1.4 billion.
Past experience has shown that well-designed programs can reduce fertility by 1.0 to 1.5 births, and such programs, if implemented now throughout the continent, can reduce the population in 2100 to or even below this low variant.
With sufficient political will and resources, well-run voluntary programs have contributed to sustained declines in fertility and population growth across much of Asia, the Middle East and Latin America and in some countries in Africa, simply by permitting people to realize their individual reproductive goals. Such programs represent a cost-effective approach to relieving population pressures on the environment, stimulating economic development, improving health and enhancing human freedom. Investing in these programs is essential to addressing Africa’s looming demographic and development challenges.
This article first appeared in humanosphere.org, covering global health, poverty and inequity.
John Bongaarts, a vice president and distinguished scholar at the Population Council, is a member of the Royal Dutch Academy of Sciences and the US National Academy of Sciences and a fellow of the American Association for the Advancement of Science. A leading international expert on population dynamics, he received the International Union for the Scientific Study of Population Laureate Award in 2013.
Bongaarts holds a master’s degree in systems engineering from the Eindhoven Institute of Technology in the Netherlands and a Ph.D. in physiology and biomedical engineering from the University of Illinois.
