December 2, 2017

The reality of human-induced climate change is now clear: Nearly all peer-reviewed articles (the gold standard for scientific work) support it. Moreover, there is a scientific consensus that humans are “extremely likely to have been the dominant cause of observed global warming since the mid 20th century.” Attention has, therefore, turned to a search for the most effective means of reducing carbon emissions. Recently, The Guardian published a newspaper report about a journal article by Seth Wynes and Kimberly A. Nicholas. The newspaper’s headline reads, “Want to Fight Climate Change? Have Fewer Children.” That is quite a statement, one that certainly deserves further examination.

For context, the international community aims to keep global warming to 2° Celsius, which requires no more than 2.1 tons of carbon emissions per person by 2050 (a dramatic reduction from the 16-18 tons per person emitted today in the United States). According to Wynes and Nicolas, this ambitious goal requires individual behavioral shifts, since they “have the potential to be more rapid and widespread … whereas improved power plant efficiency occurs on a decadal time frame.” The clear implication is that we need results today: Actions that won’t bear fruit until 2050, just 33 years away, may come too late.

While the newspaper report focuses disproportionately on how having fewer children influences climate change, Wynes and Nicolas cite other possibilities as well. Their paper – which reviews whether developed nations advise “high impact” changes to personal behavior to combat climate change – borrows estimates of carbon savings from previously-conducted governmental and academic papers. While having fewer children finished first (saving 58.6 tons per year), living car-free (2.4 tons), avoiding one transatlantic flight (1.6 tons), and buying green energy (1.5 tons) were also changes that would alleviate climate change. At first blush, the answer seems clear: We need to have fewer children!

To arrive at this eye-popping number of 58.6 tons-per-year of carbon saved, Wynes and Nicolas relied on an earlier piece that calculates the amount of carbon for which each person’s entire progeny is responsible. (As an aside, this earlier piece was accepted for publication in 2008, meaning its estimates come from a time when carbon emissions were 35% higher than they are today, so the numbers used to estimate each person’s carbon footprint are likely overinflated in the first place.) According to this method, each parent is responsible for 50% of his or her children’s emissions, 25% of his or her grandchildren’s, and so on; these figures are then totaled and divided by the number of years a contemporary person is expected to live.

Thus, the 58.6-tons figure is not actually carbon savings this year. It’s not even savings next year, nor the year after that: To arrive at such a dramatic conclusion, the authors employ an entirely different timeframe without making this clear to the reader. That is, the numbers of 58.6 tons vs. 2.4 tons for car-free living (or 1.6 tons for avoiding transatlantic flights) are not in any way comparable! Living without a car this year will save 2.4 tons in carbon emissions this year. But choosing to not have a child this year will not save a comparable 58.6 tons this year. Rather, that’s the total amount of carbon emissions saved over many, many generations (one’s entire progeny!) totaled and then averaged for each year of a woman’s expected lifetime. Hardly the same thing!

Will having fewer children have the outlandish effect the authors of the journal article propose? Almost certainly not. In fact, the benefits of having one fewer child will take centuries to materialize because the carbon savings will require many, many decades of foregone fertility before those savings are realized. Beyond this, however, there are other problems with reducing fertility. The lost human capital would be enormous. Much of our hope in reducing emissions is pegged to the development of unproven technologies but, if we lose the combined potential of millions of unborn, such developments may take longer. Calculating the costs associated with forgoing something for something ostensibly better is called “opportunity cost,” a key tenet of economics. In this case, the loss of human capital would be a huge societal opportunity cost for the small benefits of mitigated climate change.

Further, any additional reductions in fertility would have ramifications for the labor force, likely leading to labor shortages and fewer workers available to support retirees. A reduction of one child in the total fertility rate across the developed world would lead to dramatic reductions in population size over very short periods of time. These, in turn, would inevitably require governments to make tough policy choices, particularly around immigration and fertility incentives. These reductions would also make long-term population forecasting difficult for businesses and governments alike.

So, is reducing fertility really the answer to climate change? In the long term, fewer people certainly means fewer emissions. But such an approach may be unwise, especially considering that the short-term benefits would be minimal and the costs substantial. It would be, indeed, very much like throwing the baby out with the bathwater.

About the Author

Spencer James is an assistant professor in the Family Life Department at Brigham Young University.

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