PRB

The U.S. population has grown from decade to decade since its founding. But growth has slowed in recent decades, which raises the question: Could the U.S. population ever shrink? 

Based on new population projections from the U.S. Census Bureau, the answer is yes. And a better question might be when—not if—the nation will change from a growing to a shrinking population. 

What Is Driving the Slowdown, and Possible Reversal, in U.S. Population Growth? 

Recent declines in fertility and immigration have slowed growth in the share of children in the population and accelerated U.S. population aging. An aging population and falling birth rates mean that deaths will likely begin to outnumber births within the next 20 years.  

With deaths outnumbering births in all scenarios, the pace of future population growth hinges on immigration. The Census Bureau predicts that immigration will become the largest contributor to population growth, and the level of immigration will determine when (or if) the population begins to decline. 

Under their scenario with the fastest population growth rate (high immigration scenario), the Census Bureau predicts that the nation’s deaths will outnumber births beginning in 2042. The more likely scenario (main series) is that this milestone will occur in 2038. And if immigration stopped completely, the turning point could be as soon as 2033.  

Under the most likely scenario, population will peak at 369 million in 2080 and decline slowly after that. Under the low-immigration scenario, the turning point could be as soon as 2044, and if immigration stopped completely, we could see population begin to decline in the next year or two. Of all the projection scenarios, only the high–immigration scenario avoids a dip.

Compared with earlier projections, which had the United States crossing the 400-million mark by 2058, the latest scenarios present a very different picture of how the U.S. population may change. Key trends reflected in the current projections include the population lost during the COVID-19 pandemic, declines in international migration from 2017 to 2021, and rapidly falling birth rates. 

Will Any Population Groups in the United States Grow? 

The new projections also highlight that the U.S. population is expected to age dramatically. Population growth will be fastest in the oldest age groups.  

The population of centenarians, those ages 100 and older, is expected to see a nearly 12-fold increase by 2100.  

The Census Bureau projects a four-fold increase in the number of adults ages 85 and older by 2100. In 2022, less than 2% of the population, or about 6.5 million people, were ages 85 and older. In the main series projection that number rises to 17 million (nearly 5% of the total) by 2050, and to more than 27 million (7% of the total) by 2100. 

The population ages 65 to 84 is also expected to grow, although at a less rapid rate, between now and 2100. The population of adults ages 25 to 64 is expected to remain roughly constant over the next eight decades. 

At the other end of the age spectrum, the U.S. child population is expected to shrink. The United States had about 72 million children ages 0 to 17 (about 22% of the population) in 2022. That number is expected to fall to 66 million (18%) by 2050, and to less than 60 million (16%) by 2100.  

The population of young adults, ages 18 to 24, is expected to see a similar rate of decline. 

While the magnitude and timing of population aging varies across the projection scenarios, all show substantial aging of the population (see figure).

Figure. U.S. Population Growth Will Be Rapid at Oldest Ages While Younger Populations Shrink

What Are the Implications of an Older, Smaller Population? 

Population aging and shrinking have dramatic implications—affecting everything from the health care workforce to transportation infrastructure. For example, the shifting U.S. age structure may lead to higher levels of public spending on the health and economic well-being of older adults relative to young families and children. The demand for caregivers among older Americans will increase dramatically. 

The United States isn’t the first country that will face a shrinking population. Others, like Italy, are already in the thick of population loss. Countries that reach this milestone later can look to the frontrunners for guidance on navigating the seismic shifts. 

For a discussion of how communities can prepare for demographic change, watch PRB x TED: How Do We Respond to an Aging World?