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Eight Demographic Trends We’re Watching as the World Population Passes 8 Billion

Here are eight emerging demographic issues we expect to shape our world in the coming decades.

On November 15, the day the world’s total population is projected to reach 8 billion people, PRB and the Center of Excellence for Research in Generational Economics (CREG) join others in highlighting eight notable demographic trends and issues. In the 15 years between today’s population milestone and the projected Day of 9 Billion in 2037, India will overtake China in population, and Democratic Republic of the Congo and Ethiopia will grow to be among the 10 most populous countries in the world. More than 50 other countries will see fertility rates fall below replacement level, and crises driven by climate change will likely fuel migration around the world. Knowledge of the changes to come enables us to make investments today that will better prepare us for the future.

Here are eight emerging demographic issues we expect to shape our world in the coming decades:

  1. As climate change exposes societal inequalities, more attention is needed to the populations unable to migrate when crises occur. Climate change is widely predicted to drive migration within and between countries. But not all populations have the means to uproot their lives in response to climate crises, and often the most vulnerable groups are left behind. While climate migrants have received significant global attention, more should be done to strengthen the resilience of communities unable to migrate out of harm’s way.
  2. For many countries with youthful populations, the “demographic window of opportunity” opens between now and 2050. As fertility declines from high to low levels, countries experience a window of opportunity for sustained economic growth. The window is time limited, closing as the age structure matures and older adults account for a greater share of the population. For some countries, this window may only be open for 10 to 15 years, while an analysis of six countries in the Sahel suggests a window of 30 to 40 years. The actions countries take as they approach this window of opportunity are likely to have long-lasting economic effects.
  3. As the global population ages, understanding older adults’ diverse needs and contributions to families and society is essential to inform policy decisions about effective old-age support. Population aging is already a defining demographic trend of this century, and governments around the world are working to establish and fund systems to support the well-being of older adults. But these structures need to reflect the substantial differences in quality of life among older adults; for example, women generally live longer than men, but with more illness and less financial security. Focusing less on chronological age and more on the diverse characteristics of older adults will result in more effective decisions about social protection systems.
  4. Noncommunicable diseases will be the leading cause of death everywhere by 2030, and health systems must be ready. Some national health systems and many global health donors are not built to respond to this fundamental change in the burden of disease, with noncommunicable diseases such as cardiovascular disease, cancer, and diabetes overtaking infectious diseases as the leading drivers of mortality. Even as the COVID-19 pandemic revealed health systems’ fragility, greater attention and investment to prevent and respond to noncommunicable diseases are urgently needed.
  5. Demographic and societal changes will contribute to the risk of future pandemics and must be considered in the global health security agenda. Scientists and world leaders continue to evaluate lessons and recommendations drawn from the COVID-19 pandemic to inform prevention and mitigation of future pandemics. However, emerging recommendations do not adequately consider the demographic factors that may contribute to the risk of the next emerging novel zoonotic disease (that spills over from animals into human populations), including urbanization and internal migration, changes in where people get their food, and changes in gender norms. The COVID-19 pandemic underscores that such demographic and societal factors can play a pivotal role in the emergence and impact of novel diseases and must be considered in pandemic prevention efforts.
  6. Reproductive justice must be a priority even as fertility continues to decline around the world. As fertility rates fall below replacement level in a growing number of countries, leaders may see population decline as a threat. Advocates must continue to call on policymakers to support women and couples to meet their fertility ideals whether they desire many children or none. Rather than supporting facile, minimally effective incentives such as cash payments or abhorrent restrictions on reproductive freedom, policymakers must confront the intersecting gender, cultural, and economic barriers that influence fertility preferences and cause women to make tradeoffs between having the number of children they want and pursuing other opportunities.
  7. The Africa region will experience a confluence of demographic events, including significant changes in population age structure, urbanization, a shifting burden of disease, and likely climate migration. To prepare for these events, leaders must address the well-being of the region’s burgeoning youth population by harnessing the first demographic dividend through complementary investments in health, education, governance, and the economy. In addition, the relatively young populations of sub-Saharan Africa can mask that the absolute number of older adults in the region is projected to nearly triple in the next three decades. Leaders must anticipate the shift toward an aging population through adequate investments in social protection systems for seniors.
  8. In the United States, urgent investments are needed to foster better prospects for young adults, who are worse off in many ways relative to their parents’ generation. Mortality rates are stagnant or rising among every age group under age 25, with poverty, race and ethnicity, and parental education identified as important risk factors. Young adults have been disproportionately affected by the economic fallout from the COVID-19 pandemic. Reduced abortion access following the Dobbs decision will further erode the well-being of a generation of women entering their reproductive years. Together, these declines in the well-being of young people represent a crisis that warrants a robust national policy response, including urgent investments to reduce child poverty, address racial and ethnic barriers to health care access, and greatly expand the availability of mental health and substance abuse prevention and treatment resources.