One in four people alive today lives in a country whose population has already peaked and is now shrinking, according to the United Nations World Population Prospects 2024. That group includes 63 countries and areas, among them China, Germany, Japan, Italy, and Russia, and their combined population is projected to fall by 14 percent over the next 30 years. This is a genuinely new demographic era. For most of human history, sustained multi-decade population decline outside of war, famine, or plague was essentially unheard of; today it is the expected trajectory for a growing share of the world’s most populous and economically significant countries.
Which Countries Are Losing Population?
A country’s population declines when the number of deaths plus emigrants exceeds the number of births plus immigrants over a sustained period, not merely in a single unusual year. The UN’s medium-variant projection sorts every country and area into three groups based on the timing of this transition.
As of 2024, 63 countries and areas, home to 28 percent of the world’s population, had already passed their peak population size. A further 48 countries, including Brazil, Iran, Turkey, and Vietnam, are projected to peak sometime between 2025 and 2054. The remaining 126 countries, including India, Indonesia, Nigeria, Pakistan, and the United States, are expected to keep growing at least through 2054, with some of them, especially in sub-Saharan Africa, still expanding rapidly for decades after that.
The Three Global Population Trajectory Groups, 2024
| Group | Number of Countries/Areas | Share of World Population (2024) | Examples | Projected Trend |
|---|---|---|---|---|
| Already peaked | 63 | 28% | China, Germany, Japan, Italy, Russia, Spain, South Korea, Thailand | Combined population to fall 14% by 2054 |
| Peaking 2025-2054 | 48 | Not separately reported | Brazil, Iran, Turkey, Vietnam, Denmark, Netherlands, Myanmar, Argentina | Growth continues short-term, then declines |
| Growing through 2054 and beyond | 126 | Remainder of world population | India, Indonesia, Nigeria, Pakistan, United States, Bangladesh, Egypt, Ethiopia, UK | Continued growth, in some cases for the rest of the century |
Source: United Nations World Population Prospects 2024: Summary of Results, medium-variant projection.
Countries Whose Populations Have Already Peaked
China is the most consequential country in the “already peaked” group, both because of its enormous population size and because of how sharply the UN now expects it to shrink. China’s population, which stood at approximately 1.4 billion in 2024, is projected to lose 204 million people between 2024 and 2054 alone, the single largest absolute population decline of any country over that period. Looking further out, China’s population is projected to fall to just 633 million by 2100, meaning it would lose more than half its current population within roughly 75 years and return to a population size last seen in the late 1950s. Japan and Russia follow China in absolute projected losses through 2054, at approximately 21 million and 10 million respectively, though both started from a much smaller population base.
Several already-peaked countries would have peaked even earlier were it not for immigration offsetting an underlying deficit of births relative to deaths. The UN specifically flags Italy, Germany, and Russia as examples where net migration has been actively delaying population decline that low fertility alone would otherwise have produced sooner.
Countries With the Fastest Population Declines
Rate of decline and absolute size of decline are different measures, and conflating them produces misleading comparisons. A small country can post a very high percentage rate of annual decline while adding up to a modest absolute population loss, while a large country like China posts a comparatively moderate percentage decline that nonetheless represents hundreds of millions of people.
Eastern European countries, including Bulgaria, Latvia, and Lithuania, and several small island territories with high emigration rates, have historically ranked among the fastest percentage decliners globally, a pattern driven by the combination of very low fertility and substantial emigration of working-age adults to wealthier parts of the European Union.
Why Populations Shrink
Population decline results from the interaction of four demographic forces, and disentangling which force dominates in a given country matters for understanding whether, and how, the trajectory might change.
Low fertility is the single most important driver identified by the UN across the majority of already-peaked countries. More than half of all countries and territories worldwide now have a total fertility rate below the 2.1 replacement threshold, the global fertility rate having fallen from 3.3 births per woman in 1990 to 2.25 in 2024.
Population aging compounds low fertility over time, because as a population’s age structure shifts toward older ages, an ever-larger share of deaths occur among a growing elderly cohort even as the shrinking cohort of women in their childbearing years produces fewer total births, creating a self-reinforcing dynamic.
Deaths exceeding births, known as natural decrease, is now the dominant proximate cause of population decline in most already-peaked countries, rather than net emigration, which is a secondary factor in most, though not all, cases.
Net migration can either offset or accelerate decline depending on direction. Countries like Italy, Germany, and Russia have had their fertility-driven decline delayed by positive net immigration, while countries experiencing significant net emigration, common across parts of Eastern Europe and some Caribbean nations, see their populations shrink faster than natural increase and decrease figures alone would suggest.
Why Low Fertility Can Cause Long-Term Decline
A single year of below-replacement fertility does not immediately shrink a population, because of a phenomenon called population momentum: a country with a historically young age structure can continue growing for one or two more generations even after fertility falls below replacement, simply because there are still large numbers of people in their reproductive years from earlier, higher-fertility decades. This is precisely why the transition from peak population to actual decline can take decades to materialize after fertility first crosses below 2.1.
China’s fertility rate fell below replacement in the early 1990s, yet its population did not begin actually declining until around 2021 to 2022, roughly three decades later, illustrating how long population momentum can sustain growth even under sustained sub-replacement fertility.
Can Immigration Offset Population Decline?
Immigration can meaningfully delay or soften population decline, and the UN’s own analysis credits net migration with having already postponed peak population in Italy, Germany, and Russia. However, immigration alone has generally proven insufficient to reverse decline entirely in countries with very low fertility and rapidly aging populations, both because the scale of immigration required to fully offset a large fertility deficit is often politically and logistically difficult to sustain, and because migrants themselves tend to adopt fertility patterns closer to their destination country’s norm within one or two generations, limiting how much immigration alone can permanently reshape a country’s underlying demographic trajectory.
What Population Decline Means for Society
A shrinking population reshapes the practical demands placed on nearly every public institution, though not always in the direction popular intuition suggests. Labor supply contracts as the working-age population shrinks relative to the number of retirees, a shift the UN highlights starkly: in the group of 63 countries and areas that have already peaked, the number of people aged 65 and older is projected to reach 409 million by 2027, surpassing the number of children under 18 in that same group. Pension and healthcare systems designed around a much larger working-age tax base face mounting fiscal pressure as the ratio of workers to retirees narrows.
Schools, by contrast, often see falling enrollment and consolidation pressure as smaller birth cohorts move through the education system, while housing markets in shrinking regions can face oversupply and falling property values, a pattern already visible in parts of rural Japan and Eastern Europe experiencing the most acute local depopulation.
Population Decline Versus Population Aging
These two phenomena are closely linked but conceptually distinct, and conflating them obscures useful nuance. A population can age rapidly, meaning its median age rises and the share of older residents grows, without its total population size shrinking at all, if net immigration or a still-large working-age cohort offsets the effect of low fertility on total numbers.
Conversely, in principle a population could theoretically shrink in total size while aging relatively slowly, though this combination is uncommon in practice because the same underlying force, sustained low fertility, tends to drive both aging and eventual decline simultaneously once population momentum is exhausted.
What Happens Next?
The UN’s medium-variant projections are scenarios built on assumptions about future fertility, mortality, and migration trends, not guarantees, and the UN itself revised its outlook meaningfully between its 2013 and 2024 editions, lowering the projected end-of-century global population by roughly 700 million people, or 6 percent, largely because fertility fell faster than previously modeled in several of the world’s most populous countries, especially China.
This history of revision is itself informative: it demonstrates that fertility trends, the single largest driver of long-run population trajectories, are genuinely difficult to forecast decades in advance, and today’s 63-country “already peaked” list, along with the 48-country group projected to peak by 2054, should be read as a well-evidenced current trajectory rather than a fixed certainty.
Conclusion
The defining fact of this data is not any single country’s decline but the scale of the group already experiencing it: 63 countries and areas, more than a quarter of humanity, now live somewhere past its population peak, and demographers expect the number of people aged 65 and older in that group to overtake the number of children under 18 within just a few years, by 2027.
China’s trajectory illustrates how dramatically this can play out at scale, a projected loss of 204 million people by 2054 and more than half its current population by 2100, while the contrast with the 126 countries still expected to grow through at least 2054, including some of the world’s most populous nations, underscores how unevenly this new era of population decline is distributed across the globe.
Frequently Asked Questions
1. Which countries are losing population fastest?
China is losing population in the largest absolute numbers, projected to fall by 204 million people between 2024 and 2054 alone. Several Eastern European countries and small island territories post the fastest percentage rates of annual decline, though on a much smaller population base.
2. Why are populations declining?
The primary driver identified by the UN across most already-peaked countries is sustained low fertility, often reinforced by an aging population structure in which deaths now exceed births. Net emigration is a secondary factor in some countries, while net immigration has actually delayed decline in others, including Italy, Germany, and Russia.
3. Can immigration stop population decline?
Immigration has already delayed peak population timing in several countries, but it has generally not proven sufficient on its own to fully reverse decline in countries with very low fertility, both because of the scale of migration required and because migrants’ fertility tends to converge toward destination-country norms over time.
4. Which countries are expected to shrink most by 2100?
China is projected to see the largest total population decline of any country by 2100, losing an estimated 786 million people from its current size and falling to approximately 633 million, a level last seen in the late 1950s.
5. How many countries have already peaked in population?
63 countries and areas, home to 28 percent of the world’s population in 2024, had already passed peak population size as of the UN’s 2024 assessment.
6. Does a falling population mean falling standard of living?
Not necessarily and not automatically. Population decline creates specific fiscal and labor-supply challenges, particularly for pension and healthcare systems, but it does not mechanically determine economic outcomes, which depend heavily on productivity, labor force participation, immigration policy, and other economic factors.
7. When did China’s population start actually declining?
China’s fertility rate fell below the replacement level of 2.1 in the early 1990s, but its total population did not begin declining until around 2021 to 2022, roughly three decades later, due to population momentum from earlier higher-fertility generations.
8. What is population momentum?
Population momentum is the tendency of a population to keep growing for one or more additional generations after fertility falls below replacement level, because a large number of people already in their reproductive years, a legacy of earlier higher fertility, continue producing births even as each woman has fewer children on average.
9. Are any large, wealthy countries not declining?
Yes. The United States is projected to keep growing through at least 2054, according to the UN’s medium-variant projection, placed in the same group as India, Indonesia, Nigeria, and Pakistan, largely due to continued immigration combined with fertility levels not quite as low as those in China, Japan, or much of Europe.
10. How reliable are these population decline projections?
The UN’s own projections have shifted meaningfully between editions, with the 2024 revision lowering the projected 2100 global population by about 700 million compared to a decade earlier, mainly because fertility declined faster than expected in several large countries. This history suggests current 30-to-75-year projections should be read as well-evidenced scenarios rather than fixed outcomes.
Sources
- United Nations Department of Economic and Social Affairs, World Population Prospects 2024: Summary of Results, July 11, 2024
- United Nations DESA, Policy Brief No. 167, Leveraging Population Trends for a More Sustainable and Inclusive Future
- United Nations DESA, “4 Things to Know About the Latest Global Population Trends,” September 2024
- Population Division presentation, World Population Prospects 2024: Summary of Results, Clare Menozzi, July 11, 2024
