Ageing and Shrinking Populations Reshape Global Societies

Global life expectancy at birth has increased from 46 years in 1950 to 74 in 2025, with a growing number of individuals reaching centenarian status.

Ageing and shrinking populations are becoming increasingly prevalent in many countries around the world.

A growing number of governments are grappling with these dual demographic challenges, which are becoming more pronounced. The demographic pressures created by ageing and shrinking populations have significant societal impacts, affecting economic, social, and political systems.

Governments are increasingly being forced to address the economic burden of supporting a growing number of retirees who are living longer, while the number of working-age people continues to decline. These changes are already having visible effects on pension programmes, healthcare systems, and social safety nets.

In approximately 63 countries and areas, accounting for about 28 percent of the world’s population of 8.2 billion in 2024, population size peaked before 2024 and is now declining. In another 48 countries and areas, representing around 10 percent of the global population, population size is projected to peak within the next 50 years.

In the remaining 126 countries and areas, which together account for 62 percent of the world’s population, population growth is expected to continue until at least 2055, with peaks occurring later in the 21st century or beyond.

Alongside population decline, many countries have experienced a “historic reversal” in their age structures. This demographic milestone occurs when the share of people aged 65 and over exceeds the share of those aged 17 and under. In simple terms, older adults outnumber children.

The first such reversal occurred in Italy in 1995. Five years later, it was recorded in six more countries: Bulgaria, Germany, Greece, Japan, Portugal, and Spain.

By 2025, 55 countries and areas had experienced this historic reversal, with more expected to follow. Particularly striking are the cases of Italy and Japan, where the proportion of people aged 65 and older is roughly twice that of those aged 17 and younger, alongside overall population decline.

The main forces driving population ageing and decline include fertility rates below replacement level, increased life expectancy, and limited immigration. Globally, more than half of all countries and areas now have fertility rates below 2.1 births per woman, the level required for population replacement.

In many countries, fertility rates in 2024 had fallen well below this threshold. For example, South Korea (0.73), China (1.01), Italy (1.21), Japan (1.22), Canada (1.34), Germany (1.45), Russia (1.46), the United Kingdom (1.55), the United States (1.62), and France (1.64) all recorded sub-replacement fertility rates.

At the same time, global life expectancy at birth has risen from 46 years in 1950 to 74 years in 2025, with a growing number of people living to 100 years and beyond. In around 50 countries and areas, immigration is expected to partially offset future population decline.

One approach to addressing ageing and shrinking populations is for governments to recognise demographic realities and adapt policies and programmes accordingly. However, many governments remain reluctant to accept these trends and have instead adopted measures aimed at reversing them.

Around 55 countries have introduced policies and incentives designed to raise fertility rates. Yet, given current economic, social, cultural, and personal factors, it appears unlikely that fertility levels will return to replacement rates in the near future.

Governments have also implemented a wide range of policies to respond to demographic change. These include increasing taxes, raising retirement ages, boosting productivity, expanding female labour force participation, relying on labour immigration, promoting gender equality, and reducing pension and healthcare expenditures for older adults.

Most governments continue to invest heavily in pensions and healthcare for ageing populations. Some officials argue that such spending is economically unsustainable as the workforce shrinks. They claim that high expenditures on older adults generate limited economic returns and advocate raising retirement ages and encouraging longer working lives, particularly among pension recipients.

Rather than relying on state-funded programmes, some policymakers argue that families should assume greater responsibility for caring for elderly and frail relatives, as was common historically. Others suggest encouraging older adults who depend on public assistance to re-enter the workforce and pursue financial independence.

While governments play a major role in providing pensions and healthcare, the scope and nature of this role remain subjects of political and economic debate. Public opinion, however, largely supports continued government involvement.

Surveys conducted in six European countries—Britain, France, Germany, Italy, Poland, and Spain—as well as in the United States, show that most citizens recognise future financial challenges facing pension systems. Many respondents believe state pensions are inadequate and oppose reforms such as raising retirement ages or cutting services. Additionally, many working-age individuals doubt they will be able to retire comfortably.

Ageing and shrinking populations represent two of the most significant demographic trends of the 21st century. Rather than attempting to reverse these shifts, governments may be better served by acknowledging them and developing policies that effectively address the complex challenges they create.

Joseph Chamie is a consulting demographer, former director of the United Nations Population Division, and author of numerous publications on population issues.