The human population has surpassed 8 billion, with longer lifespans offsetting fewer births, but global population growth is slowing, according to the United States Census Bureau on Thursday.
The bureau estimates that the global population surpassed the threshold on September 26, a date that the agency advises taking with a grain of salt.
The disparity is caused by countries counting people in different ways
The United Nations estimated the number was passed 10 months earlier, having declared November 22, 2022, the “Day of 8 Billion,” according to a statement from the Census Bureau.
The disparity is caused by countries counting people in different ways—or not at all. Many countries lack systems for recording births and deaths. According to the bureau, some of the most populous countries, such as India and Nigeria, have not conducted censuses in over a decade.
While global population growth has remained rapid, increasing from 6 billion to 8 billion since the millennium’s turn, the rate has slowed since doubling between 1960 and 2000.
People living in old age account for a large portion of the recent increase. The global median age is now 32, and this trend is expected to continue until 2060, when it will be 39.
Countries such as Canada have been aging with declining older-age mortality, whereas countries such as Nigeria have seen dramatic decreases in child mortality under the age of five.
Fertility rates, or the number of births per woman of childbearing age, are also declining, falling below replacement levels in much of the world and contributing to a more than 50-year trend of slower population growth on average.
Demographers estimate that the minimum number of such births required to replace both the father and mother for a neutral world population is 2.1. Almost three-quarters of the world’s population now lives in countries with fertility rates close to or below that level.
India, Tunisia, and Argentina have fertility rates that are close to replacement levels.
Global fertility rates are expected to fall at least through 2060
Around 15% of people live in areas where fertility rates are lower than the replacement level. Brazil, Mexico, the United States, and Sweden have low fertility rates, while China, South Korea, and Spain have very low fertility rates.
Israel, Ethiopia, and Papua New Guinea are among the countries with fertility rates higher than replacement, up to 5. Such countries have almost one-quarter of the world’s population.
Countries with fertility rates above 5 account for only about 4% of the global population. They are all in Africa.
According to the bureau, global fertility rates are expected to fall at least through 2060, with no country expected to have a rate higher than 4 by then.