The World May Face Population Decline Later This Century — What Does This Mean for Society?

In the U.S., a baby is born every 9 seconds. A person dies every 9 seconds. An international migrant enters the country every 90 seconds. This means the U.S. gains one person every 57 seconds, according to the Census Bureau's U.S. and World Population Clock.

Meanwhile, the world population clock shows about 2.5 children being born every second. Based on these counters, it appears the global population is steadily growing.

But demographers anticipate that the population will peak over the next 55 years and then begin a rapid decline. Researchers don’t agree on what the consequences of a falling fertility rate might mean for both society and science, and that’s because population loss may look very different from one part of the globe to the next.

Read More: Prehistoric Human Populations Shifted East at the End of the Ice Age

What Is Needed for Steady Population Growth?

For the population to remain steady, the average woman needs to have 2.1 children in her lifetime. The average replacement rate, however, has been falling in the past few decades, according to a report in the American Economic Review. The U.S. is currently at a replacement rate of 1.8, and the world average for wealthy countries is 1.7, although some countries like Italy, Japan, and Spain are lower.

“Demographic change has already arrived. Over the last 25 years, fertility rates declined in every region of the world and in every World Bank country income group,” David E. Bloom, the Clarence James Gamble professor of economics and demography in the department of global health and population at Harvard T.H. Chan School of Public Health, told Discover.

In 1960, the fertility rate averaged 3.29 across member countries of the Organisation for Economic Co-operation and Development (OECD), a public policy group with more than 100 members, including the U.S.

By 2023, the OECD average had dropped to 1.54, well below the replacement rate. The global average is also expected to drop to 2.1 by 2050. This could mean the global population, currently around 8.3 billion, could peak at 10.3 billion in 2084 and then begin to decline, according to Bloom.

Dwindling Replacement Rates

So why has the replacement rate dwindled in just a few decades? Answers vary across the globe.

In the U.S., there’s a lack of desire: 57 percent of childfree people under 50 say they don’t want to be parents, according to Pew Research Center findings.

In China, the one-child policy prevented families from having more than one child from 1980 to 2015. The policy was meant to prevent a population explosion, but China is now expected to experience one of the most drastic population declines. In the next 75 years, the Chinese population is expected to decline by 786 million people, which is half of their current population, according to the United Nations. This means the size of the Chinese population in 2100 will resemble that of 1950.

In the U.S., immigration is helping to keep the population stable. But without immigration, the U.S. population would drop by 100 million by 2100, about one-third of its current size, according to research from Brookings.

What Population Decline Means for the Future

There are many ideas about how falling fertility rates will change a society. One concern is that an aging population will lack a younger workforce to provide care services or to pay the taxes needed to fund eldercare benefits or services, according to the International Monetary Fund.

Another concern is that science and innovation could be halted when the stream of people entering these fields decreases to a mere trickle. Fewer people means fewer ideas.

But some researchers caution that population growth isn’t the driver of improved living standards, according to a study in Economics and Business Review. The world population has steadily grown over thousands of years, but only in the past two centuries have technological developments been significant enough to raise prosperity levels, enabling people to live better and longer.

“With respect to economic growth, research shows that a population’s productive characteristics are more important than its size,” Bloom told Discover. “That is, it’s not the sheer number of total people as much as it is the number of healthy and well-educated people that determine productivity.”

Societies that invest in building the skill-set of the working population may be able to offset the losses from declining fertility.

Read More: We’ve Been Worried About Overpopulation for Millenia

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from the United States Census Bureau:
  U.S. and World Population Clock
• This article references information from the American Economic Review: The End of Economic Growth? Unintended Consequences of a Declining Population
• This article references information from the Pew Research Center: The Experiences of U.S. Adults Who Don’t Have Children
• This article references information from the United Nations: Population
• This article references information from Brookings: New census projections show immigration is essential to the growth and vitality of a more diverse US population
• This article references information from the International Monetary Fund: The Debate over Falling Fertility
• This article references information from the Economics and Business Review: The journey of humanity: Roots of inequality in the wealth of nations