Will the World Population Peak and Then Decline? Debates on Global Fertility and Policy

Science Weekly investigates a turning point in global demography. As birth rates fall in many countries, researchers warn against fatalistic depopulation fears while examining what a shrinking population could mean for economies, aging societies, and policy. The episode features Dean Spears of the University of Texas at Austin and Jennifer Scher of the Population Reference Bureau, who explain why global fertility is slipping, how the world might move from a population peak to decline, and what governments can and cannot do to shape family size. They discuss the origins of low fertility beyond simple gender politics, the costs of raising children, housing and childcare barriers, and the political risks of draconian measures. The episode sets up a second part that asks what a future without robust population growth could look like and what policies might be most effective.

Overview

Science Weekly investigates a turning point in global demography. While in the past century the world surged from roughly 1 billion to around 8 billion people, the trajectory is shifting. Projections from the United Nations anticipate a peak around 2084 at about 10.3 billion, followed by a potential decline. A striking takeaway is that roughly two-thirds of the world currently live in countries with birth rates below the replacement level of two children per couple, fueling debates about depopulation and its implications for aging populations and economies.

Key Voices

Economist and demographer Dean Spears of the University of Texas at Austin explains that the long-standing overpopulation anxiety has shifted as fertility falls globally. Jennifer Scher, president and CEO of the Population Reference Bureau, emphasizes that an exponential decline in birth rates is not guaranteed and that cohorts may adjust over time as life patterns shift and long-run data mature.

Drivers Beyond Contraception

The discussion moves beyond contraception to consider factors such as rising opportunity costs, costs of childcare and housing, and changing views about childrearing. India’s birth rate has fallen below replacement despite relatively low female labor force participation and persistent marriage norms, suggesting multiple pathways to low fertility exist across very different societies. The narrative also examines gender dynamics, religiosity, and the perception of what it costs to raise children.

Policy Tools and Dangers

Policy responses have ranged from financial incentives like baby bonuses and tax credits to childcare subsidies. Spears emphasizes that such carrots may adjust timing but rarely raise lifetime fertility significantly. The program also surveys the darker side of policy: coercive measures during regimes that sought to prop up populations, underscoring the immediate human rights costs and the risk of backsliding once incentives are removed. The episode flags a growing anxiety among policymakers about aging populations and the potential for right-wing, nationalist, or eugenic ideologies to seize the narrative around depopulation.