As I was growing up, there was a fear of a “dark future” defined by overpopulation—a theme portrayed in many movies and series that depicted dystopian worlds overwhelmed by a vast number of people. Some examples include What Happened to Monday, Inferno, Elysium, Terra Nova, The Titan, and even Avengers: Infinity War. All of them share a common theme: humanity will become too numerous, resulting in pollution and the overuse of available resources. In some stories, draconian measures are taken— such as strict control of reproduction or, in more fantastical cases, interplanetary migration or even genocide; but in all of them, the impact on human life is profound. Fortunately, that future will likely never materialize. However, a different kind of future is emerging: one marked not by too many people, but by too few. A future of declining birth rates, closing schools, and an aging population.
One of the constants throughout human history has been population growth. From the earliest Homo sapiens in Africa to today, humans have multiplied and spread across every continent. Since the 1800s, this growth has accelerated dramatically, resulting in soaring population numbers throughout the 20th century. Between 1920 and 1975, the global population doubled— from under 2 billion to 4 billion. According to the United Nations, in just 50 years we have doubled again, reaching 8 billion by 2025. Does this mean we’ll reach 16 billion by 2075? Absolutely not. The UN itself no longer expects another population doubling. In fact, if current trends continue, the UN projects that the global population will begin to decline by the 2070s.
The 1960s marked the peak of population growth, around 2% annual increase—an average of 66 million people added each year (births minus deaths). If that rate continued, the global population would double every 30 years. Since then, however, growth has slowed. By 2025, the annual growth rate is expected to be just 0.8%, which still represents about 65 million people—roughly the population of France. The turning point came in 2013 when the global population increased by 91 million; every year since, that number has declined.
As mentioned, with the current trend, the population will start to decline by the 2070s. The UN, however, has projected alternate scenarios. A medium-growth projection indicates that the population will begin to shrink in the 2080s, while the low-growth projection suggests this could begin as early as the 2050s. There is a high-growth scenario, but it is based on unlikely assumptions— such as an average fertility rate of 2.49 throughout the entire century. This fertility rate has not been reached in any year since 2017.
The fertility rate— the average number of live births per woman— peaked between 1946 and 1965 at around 5. By 2025, it is expected to be around 2.2, very close to the replacement rate of 2.1. This is the rate needed to maintain the current population size.
Fertility rates are declining worldwide—not only in developed nations but also in developing countries. While developed nations in Europe and North America have relied on migration to offset the effects of aging populations, what happens when the countries sending migrants no longer have excess population to spare?
Some nations, like Japan, which have not traditionally relied on immigration, have already begun experiencing population decline— Japan’s started in 2010. Since then, many other countries have followed, and now entire regions, such as Europe and East Asia, are seeing population shrinkage. Asia and the Americas are expected to begin losing population between the 2040s and 2060s, Oceania by the 2070s, and Africa—the last holdout—will begin to see population decline in the late 2080s.
The consequences of global population decline are profound and will significantly affect our everyday lives. As populations shrink, entire towns may become deserted, particularly in rural areas, due to a lack of inhabitants. The demand for new housing will plummet, halting construction projects, as there simply won’t be enough people to fill new homes. Pension systems will come under immense strain, with fewer workers contributing and a growing number of retirees drawing benefits, potentially leading to higher retirement ages and reduced payouts. Schools will shut down as the number of children drops, affecting not only education infrastructure but also employment in the education sector. Healthcare systems will also need to undergo a major transformation. As birth rates decline, the focus will shift away from pediatric care toward geriatric services. Hospitals and healthcare providers will need to invest more in treating chronic illnesses, age-related conditions, and long-term care, putting further pressure on public health budgets. The decline in population will affect the economy in the decades to come, having profound implications on economic growth and fiscal sustainability. Finally, parks may no longer echo with the laughter of children playing together, but instead be filled with seniors quietly sitting on benches, soaking up the sun and enjoying the pensions they have rightfully earned.
Countries are well aware of the challenges posed by declining fertility rates, and for years, nations like Japan and South Korea have made efforts to reverse this trend. There’s a certain irony in the fact that these same countries once implemented aggressive population control policies in the 1960s to reduce birth rates— policies that were so effective they ultimately contributed to today’s record-low fertility levels. China, after enforcing its one-child policy for four decades, is now actively encouraging couples to have more children. Yet, in many of these cases, such efforts may come too little, too late. Social norms have shifted dramatically, and many couples today either choose not to have children or face economic and social barriers that make raising large families increasingly difficult. Moreover, the increasingly desperate attempts by national leaders to reverse this trend have often become the subject of ridicule and internet memes.
The fear of overpopulation has largely faded, only to be replaced by a growing concern over population collapse. You and I— the reader and writer of this article— wishing ourselves a long and happy life, will most likely leave this world on a day when more people will share the same destiny as us than are born.
By Ernesto Santiago
April 3, 2025
Disclaimer: A large amount of the facts in this article were taken from 2024 UN Projection Data. The data is available under this link: https://population.un.org/wpp/downloads?folder=Standard%20Projections&group=Most%20used.
Citation: United Nations, Department of Economic and Social Affairs, Population Division (2024). World Population Prospects 2024, Online Edition. Licensed under CC BY 3.0 IGO Deed.
