- Authors: Dean Spears, Kevin Kuruc, Sangita Vyas, Mark Budolfson, Michael Geruso
- Working paper
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Abstract
Human activity generates carbon emissions leading to climate change. This fact has led many to conclude that future generations will be better-off if global fertility continues its current decline. We show this conclusion is incorrect because it fails to account for two countervailing benefits of a larger population, each well documented in demographics and economics: that larger population sizes have historically been a key contributor to the economic growth that raises living standards (as reflected in incomes, education, health, and longevity); and that the retiree-heavy age structure of a shrinking population means that relatively few workers exist to provide the output and amenities needed to support all. Further, the arguments in favor of lowering fertility today misunderstand the basic demographic fact of population momentum, which ensures that even instant, dramatic changes to fertility rates today can have only small impacts on total population size in the near term, while the carbon emissions intensity of human activity remains high. We assess the balance of these forces and their timing using DICE, a leading climate-economy model, to contrast a demographer-consensus Depopulation scenario with population Stabilization. We show that when modified to also include economic benefits of population, DICE (and the many variants we assess) predicts that a larger world population raises average living standards for future generations, fully accounting for climate impacts on future generations. This finding holds in even the most pessimistic climate scenarios, and even for either economic benefit considered separately. These results provide a needed quantitative input to ongoing debates on the role of population in climate policy.