In 1960, Mathematicians Said Earth's Population Would Reach Infinity Next Friday

In 1960 mathematician Heinz von Foerster and colleagues fit two millennia of population data to a hyperbolic model and famously extrapolated that human numbers would diverge to infinity on November 13, 2026, effectively predicting human extinction by crowding. The projection was at least partly tongue-in-cheek - November 13th is von Foerster’s birthday - but the hyperbolic fit outperformed conventional demographic forecasts in the 1960s and 1970s, when models repeatedly underestimated rapid growth. That historical success helped fuel alarmist narratives like The Population Bomb, even as later decades undercut the hyperbolic trajectory when fertility declines and social changes altered growth patterns.

An economist revisits the episode to show the real problem was not math but a sampling error: von Foerster treated a temporary demographic regime as permanent. Demographic behavior is historically contingent, so extrapolating recent trends without accounting for structural shifts produces absurd long-term forecasts. Contemporary fears have flipped to underpopulation in wealthy countries, yet global fertility remains near replacement and UN projections put world population near ten billion by 2100. To underscore the point, the economist offers a playful counter‑extrapolation using Japan’s current decline that would depopulate Earth centuries hence - illustrating how simple exponential or hyperbolic extrapolations mislead when they ignore changing human behavior and institutions.