Study Shows that Sustainable Development Goals Will Reduce Population Growth

Everyone knows that the UN’s 2015 Sustainable Development Goals were intended to literally make the world a better case. But a recent analysis shows how they might accomplish that in ways that may not have been expected. Based on an analysis by the International Institute for Applied Systems Analysis (IIASA) and the Asian Demographic Research Institute (ADRI) at Shanghai University, achievement of these goals could result in a significant decrease in population growth.

While none of the 17 goals explicitly seek to reduce population growth, a number of them contribute to that result. The goals are aimed at fighting poverty, reducing inequality, hunger and sickness, as well as addressing climate change, while leaving nobody behind. They include enablers such as quality primary and secondary education for all children, improved sanitation, and reduced child mortality. While it may not be intuitively obvious that these actions would reduce population growth, according to this study, they will.

It’s hard to overstate the importance of this finding in the context of challenges currently threatening our continued survival on this planet. According to IIASA World Population Program Director Wolfgang Lutz, "The future of world population growth matters for our efforts to improve the human lot and our impacts on the natural environment. The sizable effect on global population growth provides an additional rationale for vigorously pursuing the implementation of the SDGs."

Looking in the factors that determine population growth, we look at fertility rate and the number of children per family. Two factors have led to a decline in this number: child survival rate, and the increased cost of raising children. Clearly, the SDGs will help improve the survival rate of children.

Also critical, says researcher Samir KC, "are the effects of increasing female education on lowering birth rates in developing countries, and the health target that includes universal access to reproductive health services." Achieving these two goals, the study showed, would lead to reduced fertility rates in much of the developing world.

Population growth is already slowing down. Fertility rates have dropped from around 5 children per woman in the 1950’s to roughly half of that today in much of the world. As long as the birth rate exceeds the death rate, population will grow. A birth rate below about 2.1 children per woman would tend to lead to population shrinkage.

According to the IIASA analysis, while the population in Year 2100 might be expected to anywhere from 9.5 to 13.5 billion people without the SDGs in place, with the SDGs, they are forecasted to fall between 8.2 to 8.7 billion. The model also show the population peaking at around 9.2 billion in 2065 and then coming down, whereas the background cases do not yet peak by 2100, though some do level off. One reason for the peak is that it takes some time for the realization that more children are surviving to work its way into cultural consciousness. Complexities include the age distribution of a given population. If, for example, a given population is relatively young when it hits the replacement rate of 2.1 children per mother, there will likely be an overshoot before stabilizing at a zero-growth level.

The forecasts are based on the assumption that the SDGs are substantially met by 2030.

A lot of people talk about population growth as “the elephant in the room,” when it comes to environmental issues. After all, the planet would clearly be in better shape if there weren’t so many of us. While some places, like China, have tried draconian measures such as making it illegal to have multiple children, which included forced sterilization of adults who violated the policy, modern thinking actually shows that improving quality of life is the most benign and most effectively approach in the long run. This idea was extensively developed in the classic text by Donella Meadows entitled Limits to Growth.

Image credit: Abel et al. 2016 Courtesy of International Institute for Applied Systems Analysis