HEALTH

Eight Billion, and Slowing

2022 CE

History · Contemporary · Holocene · Meghalayan

In November 2022, world population passed eight billion, eight times what it was two centuries earlier. The growth curve, though, is bending: fertility has fallen below replacement in most of the world, each decade adds fewer people than the last, and the most recent projections place a peak before the century is out. What follows depends on fertility: should it stay low, humanity would enter something it has rarely known, a sustained global decline.

Why it matters

Nearly every event before this one unfolded among thousands or millions of people; for almost all of its history, humanity numbered fewer than two billion living at once. The world of eight billion is the anomaly, and it was built in ten generations. The coming peak reframes the future: the hard questions shift from endless growth to ageing societies, and to what a smaller humanity would choose to keep. The timeline's rightmost edge is not a trend but a turning.

Dating & uncertainty

The United Nations designated 15 November 2022 as the symbolic day of eight billion; the real crossing is uncertain by months, perhaps years. The timing of the peak, and its height, are less settled still. Projections published in 2014 saw no end to growth before 2100, giving an 80 percent chance of a world of 9.6 to 12.3 billion by then; ten further years of falling fertility have since pulled the expected peak earlier and lower.

Sources

1. Gerland et al. (2014), Science · World population stabilization unlikely this centurydoi:10.1126/science.1257469
2. Spears et al. (2024), PLOS ONE · Long-term population projections: scenarios of low or rebounding fertilitydoi:10.1371/journal.pone.0298190
3. United Nations, Department of Economic and Social Affairs · Day of Eight Billion. Institutional source: designation of the symbolic date, accessed 2026-08-30.

Our species’ history as one day

23:59:581.1 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day