Long-Term Benefits of Curbing Human Population Growth

Abstract

The human population’s continuing growth, coupled with the dual effects of demographic transition, living longer, and increasing individual consumption, are placing unbearable strain on Earth’s finite resources. Rapid population growth and its consumption has had devastating consequences for biodiversity and natural ecosystems. Despite concern in high-income countries surrounding declining fertility rates, in reality, the world’s population has steadily risen by around 80 million people per year, every year, since 1975. High-income countries also have vastly higher consumption and disproportionately contribute to poor environmental outcomes compared to low- and middle-income countries. But the rate of consumption increases with economic development, so it would be remiss to ignore high population growth in developing countries and its future impacts. While fertility rates are declining globally, nations in sub-Saharan Africa are currently growing the fastest and this region’s fertility rate is reducing at a much slower pace, likely associated with slower declining rates of infant mortality. We provide an assessment of the realism of current world population projections from three global sources. Based on our analysis of projected national infant mortality and fertility rates, the most-plausible end-of-century population range lies between 9.3 billion and 14.8 billion. Smaller populations and lower growth rates are needed to reduce pressures on the planet and its ecosystems, as well as human health and standards of living that depend on a functioning biosphere. In particular, global ecological damage already created by developed countries is most harming those in developing countries, which will be magnified by continued rapid population growth in those regions, but can be minimised through a concerted focus on reducing child mortality.

Keywords: global population projections, fertility, infant mortality, over-population, family planning, child health

JEL Classification: I14, I15, I18