The Optimal Global Population: An Economic Analysis

Abstract

The global population recently surpassed 8 billion, reigniting old debates about the optimal population size. These debates are not merely interesting, but have important implications, especially in an era of growing concerns about climate change and the unsustainable depletion of natural resources. Yet though the question of population size has been explored within diverse fields, from philosophy to biology, few have attempted to address it through the lens of economics. Given that economics studies human behavior as a relationship between given ends and scarce means and that scarce means are generally agreed to be the primary limiting force on population size, the discipline has the potential to offer valuable insights regarding population optimization. This paper explores that potential by applying principles from the field of economics in assessing the optimal global population size. Specifically, it draws on the economic concept of utility maximization, examining four specific measures of utility—short-term total utility, long-term total utility, short-term per-capita utility, and long-term per-capita utility—and assessing what population size would maximize each. It concludes that while the optimal population has not yet been reached in terms of short-term total utility, in terms of the other three measures it has already been surpassed—in some cases, significantly. However, it acknowledges the optimal population size is not a fixed number but rather depends highly on largely exogenous factors, such as technology and lifestyle choices. It also warns against the rash adoption of policies to aggressively bring the global population to a perceived optimal level.