The End of Doom Read Online Free PDF Page B

demographers at the International Institute for Applied Systems Analysis counter that this prospect is unlikely. The chief difference between the two population forecasts is the issue of the education of women. The analysis done by Lutz and his colleagues takes into account the fact that the education levels of women are rising fast around the world, including in Africa. “In most societies, particularly during the process of demographic transition, women with more education have fewer children, both because they want fewer and because they find better ways to pursue their goals,” they note. Given current age, sex, and educational trends, they estimate that world population will most likely peak at 9.6 billion by 2070 and begin falling. If, however, the boosting of educational levels is pursued more aggressively, then world population will instead top out at 8.9 billion in 2060 and begin dropping. Let us turn now to a fuller consideration of the theories and data that underpin the latest projections of global demographic trends.

    Liberate Women, Reduce Population
    So why is human fertility falling even as food has become generally more plentiful? Demographers, economists, and evolutionary psychologists have all contributed to a vast and ever-growing literature on this subject. All their explanations converge on the notion that as people become wealthier and more educated, they tend to switch from having more children to having fewer healthier and more highly educated children. Demographers call this the quantity-quality trade-off.
    Falling fertility rates are overdetermined—that is, there is a plethora of mutually reinforcing data and hypotheses that explain the global downward trend. These include the effects of increased economic opportunities, more education, longer lives, greater liberty, and expanding globalization and trade, among others. The crucial point is that all of these explanations reinforce one another and synergistically accelerate the trend of falling global fertility.
    Even more interestingly, all of them emphasize how the opportunities afforded women by modernity produce lower fertility. Let’s briefly consider some of the fascinating contemporary research on the underlying causes of the demographic transition and what will likely happen to future human population growth.
    First, recent research applying insights from evolutionary biology shows that people are not reproductive automatons driven remorselessly by blind instinct to maximize the number of their offspring, as most other species are. For example, research in 2008 by University of Michigan evolutionary biologist Bobbi Low and her colleagues analyzed the reproductive patterns of women in 170 countries. Their study, “Influences on Women’s Reproductive Lives: Unexpected Ecological Underpinnings,” in the journal Cross-Cultural Research, uses insights based on life-history theory. This approach suggests that when the risks of mortality are high, women tend to reproduce more frequently (to increase the probability of some offspring surviving to maturity) and early (to ensure reproduction before they die). In fact, Low and her colleagues found that when women can expect to live to age sixty and above, the number of children they bear falls by half. Another study in 2013 by Low and her colleagues has bolstered their finding that expecting to live beyond age sixty dramatically lowers fertility.
    Looking at data from various countries confirms that fertility rates do drop as the average life expectancy of women crosses the threshold of age sixty. Consider Iran. In 1970, average life expectancy for Iranian women was fifty-four and total fertility was 6.3 children. Today, Iranian women have an average life expectancy of seventy-five and bear 1.9 children. What about Bangladesh? In 1970, female life expectancy was forty-four, and they bore 6.6 children. Today, Bangladeshi women live an average of seventy years and average 2.2