World population tops 8 billion, but there are signs growth is slowing
In the 2006 dystopian action film Children of Men, humanity is in a bit of trouble. For reasons which aren’t wholly understood, humanity has experienced 18 years of infertility. The youngest human on the planet is now an adult and there are no signs that any new people are on the way. Every death decreases the total human population and we’re a single lifetime away — less, actually — from complete annihilation.
The movie takes place in the year 2027, five years into our real future, and the data suggests we’re getting ready for the exact opposite problem. At the turn of the millennium, as the world was waiting for their computers to explode when the clock struck midnight, the global human population had barely crested 6 billion. Now, a little more than two decades later, we’ve hit another milestone. According to a United Nations projection, the global human population topped 8 billion people on Nov. 15. That's pretty impressive for a hairless species of intelligent primates, but it's got nothing on ants.
They attribute population growth to improvements in public health, nutrition, hygiene, and medicine, all of which have reduced infant and early life mortality and kept people alive longer. According to the United Nations’ World Population Prospect 2022 report, global life expectancy reached 72.8 years on average in 2019, an increase of roughly nine years since 1990. They anticipate that life expectancy will increase another five years, to an average of 77.2 by 2050.
The Human Cube: The volume of humanity
Of course, fertility rates play an important role in population increase or decline. Those rates remain high in some parts of the world but appear to be slowing down overall. It took approximately 12 years for the population to grow from 6 billion to 7 billion, and another 12 years to get to 8 billion. We might have expected the last billion to happen more quickly, owing to there being more people to have kids, but that wasn’t the case. Moreover, the United Nations projects that we won’t reach 9 billion until 2037, 15 years from now.
That’s largely due to declining birth rates. Global fertility rates average 2.3 births per female, over the course of a lifetime. That’s down from five births apiece in 1950, and is expected to decline to 2.1 in the next three decades. Although, those numbers vary wildly from culture to culture. In fact, more than half of the expected population growth between now and 2050 is expected to occur in just eight countries. The Democratic Republic of the Congo, Egypt, Ethiopia, Nigeria, the Philippines, the United Republic of Tanzania, and India are expected to have the highest levels of growth. It’s predicted that India will surpass China as the most populated nation on Earth sometime in 2023.
There’s some uncertainty in these numbers, as they rely heavily on population growth in the short-term to predict growth down the line. That’s because if there are fewer people born today, then there are necessarily fewer people to have babies a generation from now. To crunch the numbers, scientists run dozens of simulations with different variables, then they average them to make a prediction about how the human population will trend over the rest of the century.
Recent updates to the projections, taking into account shifting fertility rates as well as the impact of the COVID-19 pandemic, reveal a future Earth with fewer people than we previously expected. Looking further into the future, the global human population is expected to reach 10.4 billion sometime in the 2080s, at which point it should plateau for the rest of the century. The current projection contrasts with a previous one which calculated a population of 11.2 billion by 2100.
While the numbers are shifting downward, population growth remains positive overall and there’s little risk of a species-ending drop in population like the one seen in Children of Men. Instead, the United Nations warns of another impending threat, the increased climate pressure a growing human presence will place on the ecosystem. Maybe a billion fewer people 80 years from now isn’t a bad idea.
