After the spike Population, progress, and the case for people

Associate professors of economics at the University of Texas, Spears and Geruso make the counterintuitive case here that on a planet whose population leaped from 4.86 billion in 1985 to 8.19 billion 40 years later and where climate change has already landed in our midst, our best solutions going forward will derive not through depopulation, in which a peak population of 10 billion could, given decreasing global birth rates, drop to as low as 2 billion in 300 years, but rather by population stabilization. Some of their arguments: a more populous future would generate better ideas for raising the world's standard of living, more people wanting the same thing creates greater specialization of products and talent, and problems requiring massively funded solutions can be addressed more affordably by larger populations. These ideas will challenge or even frustrate readers--for example, the authors decline to estimate how many people a "stabilized" world population might total--but, without blinking, Spears and Geruso have started an essential conversation on how humans might realistically address the vexing challenges of population change.

As the global population growth rate begins to decline, governments should make concerted efforts to keep population replacement levels steady, according to this stimulating study. Economists and demographers Spears (Where India Goes) and Geruso propose that the world's population will spike at "10 billion within a few decades" and then will decline precipitously. Depopulation would be disastrous at such a scale--not only for society (since a population that trends more elderly triggers myriad challenges) but also, the authors intriguingly assert, for the environment. Global depopulation, rather than reduce environmental degradation, would, with a shrinking working-age population, slow down technological progress, raise the fixed costs of doing business, and decrease funding for the very governments and programs that defend the environment. Thus, the authors advocate for a government-led effort to "stabilize" the global population at 10 billion, through gentle social-welfare methods like cash allotments to couples who choose to have children. The authors make a strong argument that such a decline really is on the horizon, noting that "nobody fully understands low birth rates," since many former commonsense explanations like women's increased rights have begun to be dismissed by researchers. Though somewhat dry, this offers important food for thought for those concerned about climate change. (July)