Population puzzle unfolding

October 18, 2025

Global population trends indicate that in the coming decades, the world may face sustained depopulation , a phenomenon with potentially profound economic and social i m p l i c a t i o n s . I n their book After the Spike, Dean Spears and Michael Geruso, associate professors of economics at the University of Texas at Austin, argue that population decline could slow global progress and reduce innovation, challenging the assumption that a smaller population is inherently beneficial for the environment.

They stress that the time to address depopulation is now, as developing effective solutions could take decades. A shrinking population would affect global living standards and infrastructure. Larger populations generate networks, markets, and resources that make societies more efficient and innovative. Public transportation, green energy infrastructure, vaccines, and cures for rare diseases are examples o f advancement that rely on a critical mass of people to support a n d i m p l e m e n t them.

Historical data from the past two centuries show that expanding populations have coincided with u n p r e c e d e n t e d improvements in health, education, longevity, and economic security. Retreating to a smaller world could stall these gains. Depopulation occurs when birth rates fall below the replacement level of roughly two children per adult, a trend already evident in many countries. Two-thirds of the global population now lives in countries where fertility rates are below this threshold. Even after decades of decline, populations will continue shrinking unless birth rates rise significantly.

Historical evidence from Japan, Italy, and China shows that policy measures to increase fertility have had limited success, with temporary reversals often driven by immigration rather than sustained higher birth rates. Immigration cannot counteract global decline, as births and deaths are the primary determinants of population growth.

The implications are particularly significant for India, home to onesixth of the world’s population. If Indian fertility continues below replacement levels, it could shrink the contribution of Indian society to global markets, innovation, and knowledge. Depopulation is not merely a national issue; the economic and technological benefits of larger populations cross borders, influencing global progress.Spears and Geruso caution a g a i n s t f r a m i n g depopulation debates through ideological or political lenses. They emphasize that stabilizing population growth—not reducing it—is essential to maintaining global d e v e l o p m e n t , infrastructure, and innovation. A declining population could reduce the scale of human collaboration and limit the world’s capacity t o s o l ve co m p l ex challenges, highlighting the need for immediate research and policy attention.