HEALTH

The First Billion People

~1804 CE

History · Contemporary · Holocene · Meghalayan

Humanity passed one billion people around 1804, after some three hundred thousand years of existence, as the demographic transition opened in Europe.

The crossing of the first billion inhabitants, conventionally placed around 1804, occurs after about three hundred thousand years of the species' existence. It coincides with the opening, in Europe, of the demographic transition, a process in which mortality declines under the effect of food, hygiene and medicine, while fertility remains high. The gap between the two curves constitutes the entire mechanism of growth: for one to two generations, the number of children per family remains that of a regime in which many died in infancy, whereas a far higher proportion now reaches adulthood. Growth abates only with the later decline of fertility. The second billion is reached 123 years later, the fifth in thirteen years.

Why it matters

Almost all of the species' demographic growth is concentrated in the last two centuries. The transition producing it, combining lengthened lifespan and reduced family size, has since extended to most societies and remains under way across much of Africa.

Dating & uncertainty

No census documents the crossing; demographic reconstructions conventionally place the first billion between 1800 and 1804. The demographic transition, characterised by the decline of mortality preceding that of fertility, then begins in Europe.

Our species’ history as one day

23:58:591 min 1 s before midnight

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