HEALTH
Eight Billion People
2022 CE
History · Contemporary · Holocene · Meghalayan
World population passed eight billion in November 2022, eight times its size two centuries earlier, while growth slows and fertility falls below replacement across most of the world.
World population passed eight billion in November 2022 according to the United Nations Population Division, eight times its size two centuries earlier. Growth is slowing: fertility has fallen below replacement level across most of the world, each decade adds fewer people than the last, and recent projections place a maximum before the end of the century. A projection is not a forecast of events but the arithmetical unfolding of a hypothesis: a number of children per woman, a mortality schedule and migration are posited, then the generations are computed. A difference of a tenth of a child per woman, imperceptible over a lifetime, multiplies from generation to generation and shifts the expected 2100 total by billions, which explains why ten years of falling fertility sufficed to bring the projected maximum both nearer and lower.
Why it matters
Humanity numbered fewer than two billion people simultaneously for almost the whole of its existence, and most of the events on this timeline took place in populations of a few thousand to a few million individuals. The present situation is therefore atypical and recent, constituted over some ten generations. The expected reversal moves the questions posed to societies from growth towards ageing and contraction.
Dating & uncertainty
15 November 2022 was designated a symbolic date by the United Nations, the actual crossing being uncertain by several months. The date and level of the maximum are considerably more so: projections published in 2014 did not see growth stopping before 2100 and gave eight chances in ten for a population between 9.6 and 12.3 billion at that date.
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