The decline in birth rates, an aging population, and slowing immigration are posing new challenges for economic growth, the labor market, and the country’s social sustainability.
The United States is heading toward a turbulent demographic scenario. A sustained drop in birth rates, population aging, and slower immigration could reduce the country’s population to 226 million by the year 2100, according to projections from the U.S. Census Bureau.
These issues were discussed during the briefing “America’s Incredibly Shrinking Population,” held by American Community Media (ACoM), which brought together experts in public health, economics, and environmental sustainability.
Falling Fertility as the Core Driver of Change
Dr. Ana Langer, Director of the Women and Health Initiative at the Harvard T.H. Chan School of Public Health, explained that population growth is determined by four main factors: fertility, mortality, migration, and age structure.
“In 1970, the global fertility rate was nearly five children per woman. By 2024, it stands at approximately 2.2,” Langer said. The decline is widespread: in Latin America and the Caribbean, the average dropped from 4.5 to 1.9; in Asia, from five to 2.1; and in the United States, from 3.5 in the 1960s to 1.6 today.
According to Langer, these figures reflect a complex combination of economic, social, and cultural factors, including the high cost of living, lack of affordable housing, the rising price of childcare, and difficulties balancing work and family life. “The Department of Labor estimates that an American family spends an average of 16% of its income on caring for a single child,” she noted.
Shifts in personal expectations and priorities also play a role. “Twenty-five percent of respondents strongly agree that overpopulation and climate change contribute to their discomfort with raising children on a planet in crisis,” Langer said. In that sense, she emphasized that for a growing number of people, choosing not to have children is a deliberate decision rather than a circumstantial one.
Perhaps most revealing was the emphasis Langer placed on gender inequality. “Women continue to shoulder most domestic and caregiving responsibilities, even when they fully participate in the labor market,” she explained, noting that this imbalance directly influences the postponement of motherhood or the decision not to have children at all.
Economic Consequences of an Aging Nation
Anu Madgavkar, a partner at the McKinsey Global Institute, addressed the socioeconomic shifts that population decline could trigger. “There will be fewer young people and many more older adults. That will force us to rethink our assumptions about how economies grow,” she said.
According to Madgavkar, a shrinking working-age population could reduce economic growth by up to 1.2 percentage points in several countries. In the United States, where annual growth typically ranges between 1% and 2%, such a drop would be significant. At the same time, pressure on systems such as Social Security will intensify as fewer workers support an aging population.
The economist stressed that reversing declining birth rates is not an immediate solution. “Even if we increased fertility today, we would not see economic benefits for the next 20 to 25 years,” she explained. For that reason, she argued that short- and medium-term responses should focus on productivity, labor policies, and social adaptation.
Madgavkar also highlighted the role of technology. “More than half of the work done in the United States today has the technical potential to be enhanced by artificial intelligence,” she said, clarifying that this does not imply mass job losses but rather a transformation of work that will require reskilling and new productive models.
Population, Consumption, and Environmental Crisis
Philip Cafaro, a professor at Colorado State University, offered a critical perspective from the standpoint of environmental sustainability. While acknowledging that the population of the United States and the world continues to grow, he argued that the central issue lies in the ecological impact of today’s consumption patterns.
“A hundred years ago, there were about two billion people. Today, there are more than 8.2 billion—wealthier, more powerful, and using far more intensive technologies,” Cafaro said. That growth, he added, is directly linked to environmental degradation, including melting glaciers, ocean acidification, unprecedented wildfires, and massive biodiversity loss.
For Cafaro, demographic debates cannot be separated from consumption. “It’s not just how many of us there are, but how much we take. We are demanding too much from the planet,” he said. In that sense, he advanced a provocative argument: rather than pursuing policies to boost birth rates or indefinitely expand immigration, developed societies should seriously consider stabilizing—and even gradually reducing—their populations as part of a long-term sustainability strategy.