Population growth is inevitable for the next few decades, but we will have a more sustainable future with fewer, rather than more people. Population growth over the past half century is intimately bound up with the ecological disaster that we face in a world of business as usual. Bringing population to a halt sooner rather than later is important for all of us and there
is some good news on this front from researchers at the Wittgenstein Centre for Demography and Human Capital in Vienna, which is a collaboration of IIASA and the Vienna Institute for Demography. They have published a new book with accompanying online resources to help us understand their new population projections that take not only age and sex into account (per the United Nations projections), but also education (a major component of human capital). When they take into account the rising level of education among young women around the globe, their medium projection suggests that population size could peak at about 9.4 billion in the 2060-2080 period. This is a sooner peak and a smaller number of people than implied by the United Nations’ projections, which do not take educational attainment into account. Fertility is closely associated with female education, so as education increases, we can reasonably project that fertility will also go down.
Note, by the way, that these are the same sets of projections from which estimates of the population by religious affiliation were prepared by Pew Research in collaboration with IIASA and VID, as I discussed earlier. Remember that religion per se is not a hindrance to a decline in fertility. There are numerous Muslim majority countries, for example, with below replacement fertility, most notably Iran. And, of course, Catholic Christians have dramatically lowered their fertility over the past few decades, with Catholic majority countries of Southern Europe having among the lowest levels of fertility in the world. As I have said repeatedly, it is not religion, but rather the fundamentalists within a religion group that tend to promote high fertility, almost always in the context of second-class status for women. Education for women is the key remedy.
At the same time, the Wittgenstein Centre researchers argue that an increasingly better educated older population (which the world has been experiencing over the past century) means that an increasing fraction of the population that is older is not predictive of a decline in productivity and thus of economic malaise. Indeed, the opposite very well may prevail, suggesting that aging and eventually declining populations are not the end of the world. Indeed--they are signs of sustainability.