The future of world population growth matters for future human well-being and interactions with the natural environment. We show the extent to which world population growth could be reduced by fully implementing the Sustainable Development Goals (SDGs) whose health and education targets have direct and indirect consequences on future mortality and fertility trends. Although this assessment is consistent with the Shared Socioeconomic Pathways scenarios used in the Intergovernmental Panel on Climate Change context, it is inconsistent with the prediction range of the United Nations projections for which we present sensitivity analyses and suggests that their range is likely too narrow. Given our assumptions, the SDGs have a sizable effect on global population growth, providing an additional rationale for vigorously pursuing their implementation.

Abstract

Here we show the extent to which the expected world population growth could be lowered by successfully implementing the recently agreed-upon Sustainable Development Goals (SDGs). The SDGs include specific quantitative targets on mortality, reproductive health, and education for all girls by 2030, measures that will directly and indirectly affect future demographic trends. Based on a multidimensional model of population dynamics that stratifies national populations by age, sex, and level of education with educational fertility and mortality differentials, we translate these goals into SDG population scenarios, resulting in population sizes between 8.2 and 8.7 billion in 2100. Because these results lie outside the 95% prediction range given by the 2015 United Nations probabilistic population projections, we complement the study with sensitivity analyses of these projections that suggest that those prediction intervals are too narrow because of uncertainty in baseline data, conservative assumptions on correlations, and the possibility of new policies influencing these trends. Although the analysis presented here rests on several assumptions about the implementation of the SDGs and the persistence of educational, fertility, and mortality differentials, it quantitatively illustrates the view that demography is not destiny and that policies can make a decisive difference. In particular, advances in female education and reproductive health can contribute greatly to reducing world population growth.