Updated Nov 15, 2022 - World

The world is getting older and growing slower

Global fertility rate, 1974-2020
Data: World Bank; Chart: Tory Lysik/Axios Visuals

The global population is surpassing 8 billion this week — despite slowing fertility rates and aging populations, according to the U.N.

What we're watching: The average human is older than they used to be. Earthlings' median age in 2022 is 30.2 years old compared to 20.6 in 1974 when the global population was half what it is today, according to Our World in Data.

  • An aging population can be positive sign — people living longer and having fewer kids. Smaller families can mean women have better access to reproductive health care and are more confident their kids will live to be adults themselves.
  • But aging populations can also lead to stunted economic growth if elderly, non-working generations end up outnumbering the active workforce in a particular country.

Age structures vary drastically by country. Japanese nationals have a median age of 49, while for Nigerians, the median age is just 17.

  • Women typically give birth to 2.4 children in their lifetime today, compared to 4.3 in 1974.
  • A fertility rate of 2.1 is generally considered "replacement level" — meaning there are enough births for the new generation to exactly replace the last generation. 60% of the population lives in countries that are at or below that fertility rate, according to U.N.

Many high-income countries have watched birth rates plummet — leading to population decline in more than 40 nations, including Singapore, Japan, Italy and Russia.

  • Jennifer Sciubba, Wilson Center scholar and author of 8 Billion and Counting, told Axios, told Axios she is concerned about the growing phenomenon of rapidly declining fertility rates as it could be a sign of systems not effectively serving women.
  • She and other population experts are also concerned about a future where fewer people are working to support much larger, longer-living, elderly generations. Immigration will increasingly play an important role in preventing this kind of worst-case scenario in many countries — including the U.S.

The other side: Meanwhile, nearly 3 out of every 10 births worldwide last year took place in sub-Saharan Africa, according to Pew Research Center.

  • The birth rate in sub-Saharan Africa is double the global average at 4.6 births per woman. Such high birthrates are often a sign of troubling social and economic circumstances.
  • For example, if women in a country have an average of four or five or more children, "I bet you anything, it doesn't have great health care and girls don't get to go to school," Sciubba said.

The bottom line: As the global population continues to grow, the human experience — including life expectancy and family size— varies drastically depending on where we are born.

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