According to a report published by the United Nations, fertility rates around the world are falling faster than expected and this seems likely to lead to a decline in the world population before the end of the century.
More than 60 countries and regions, including Italy, Japan, Russia and China, reached their population peaks in 2021, according to the report published on Thursday. That means 1 in 4 people in the world lives in a country that has reached its population peak.
Changes in population growth and fertility rates are closely monitored because they have major social and economic impacts worldwide. The number of people on Earth also has an impact on the planet itself, affecting consumption rates, energy use, industrial production, resource availability and, to some extent, the rate of human-induced climate change. The global fertility rate is currently 2.25 births per woman, one child less per woman than in 1990.
“The demographic landscape has changed dramatically in recent years,” Li Junhua, assistant secretary-general for economic and social affairs at the United Nations, said in a news release. The report predicts that the world’s population will continue to grow over the next few decades — from 8.2 billion people in 2024 to a peak of about 10.3 billion people in 50 to 60 years. But it won’t grow forever: The global population is expected to return to 10.2 billion people by 2100, 6% lower than U.N. experts predicted a decade ago.
The UN’s previous population assessment, released in 2022, predicted humanity could reach 10.4 billion by the end of the 2000s, but low birth rates in the world’s largest countries, including China, are among the reasons why the population peak could occur earlier than expected.
More than half of all countries have a fertility rate of less than 2.1 children per woman, known as the “replacement rate” because this is the number of children each woman needs to have on average to prevent population decline. Another 48 countries, including Vietnam, Brazil, Turkey and Iran, are expected to see their populations peak in the next 30 years.
India’s population of 1.4 billion is set to become the world’s most populous country, surpassing China’s by 2022. According to the report, India’s population is expected to continue growing until mid-century.
But China’s population is shrinking. “China has seen a very rapid and very significant decline in the number of children born over the last few years,” said Patrick Gerland, head of the Population Estimates and Projections Division at the United Nations Population Division.
“The changes that China has experienced over the last generation have been among the most rapid in the entire world,” Gerland said.
Without immigration, the United States would also face population declines — one of about 50 places projected to continue growing because of immigration gains. The U.S. population is projected to grow from 345 million in 2024 to 421 million by the end of the century.
The country’s growth will likely exacerbate problems around consumption, greenhouse gas emissions and other drivers of global warming. A larger population also means more people will be exposed to climate risks, such as droughts, heat waves and other extreme weather events that global warming intensifies. “Just because a challenge is 60 years away doesn’t mean it doesn’t make sense to talk about it now,” says Dean Spears, an associate professor of economics at the University of Texas at Austin.
“Decades from now, people will be talking about these new population shifts with the same level of academic and social interest as we talk about climate change,” Spears said.
Other countries expected to continue growing through 2054 include India, Indonesia, Pakistan and Nigeria. In some parts of Africa, such as Angola, the Central African Republic, the Democratic Republic of the Congo, Niger and Somalia, the population is growing rapidly and is expected to double between 2024 and 2054, according to the UN.
But adding more people to the planet doesn’t necessarily accelerate the pace of climate change. Many of the fastest-growing regions of the world are the ones that have historically contributed the least to global warming. These same regions are often disproportionately affected by climate change.
The report noted a recovery in life expectancy levels after the pandemic hit them. Globally, life expectancy in 2023 was 73.2 years. This is up from the pandemic low of 70.9 in 2021 and the pre-pandemic low of 72.4 five years ago. Global life expectancy is projected to reach 81.7 years in 2100.
As life expectancies increase and fertility rates decrease, the world’s population will age. Projections suggest that those aged 65 and over will outnumber those under 18 by 2080. By 2023, those aged 65 and over will outnumber those aged 65 and over by almost 3 to 1.
This article was originally published on NBCNews.com