The World’s Population Now - and where it’s heading!
- Tom McAndrew
- Oct 11
- 7 min read
You’ve probably heard the headline numbers: there are roughly eight billion people on Earth, the world keeps growing, but not everywhere at the same speed. That’s the short story - the longer, more interesting story is how patterns of birth, death, migration and ageing are reshaping the planet’s human geography. This article walks through the most current trends (as of the United Nations’ 2024 assessment and recent analyses), explains why those trends matter, and lays out the main projections for 2050 and 2100 so you can see the different futures demographers imagine.
The headline numbers are straightforward but important. In 2024 the global population passed roughly 8.1 billion people. Under the UN’s medium-fertility scenario - the baseline used by most commentators - the world is projected to have about 9.6 to 9.8 billion people by 2050 and around 10.2 to 11.2 billion by 2100 depending on the variant you read. Those figures are no longer simply ‘more and more’: recent revisions have nudged the probable peak forward in time and lowered some long-term estimates compared with older projections. In plain terms, the world will almost certainly add another billion people or so by mid-century, but after that the path is less certain and depends mainly on how fast fertility falls in the countries that still have high birth rates.
Why the change to previous thinking? Two linked processes are driving the shift. First, fertility - the average number of children per woman - has declined dramatically worldwide since the 1960s. Where women once had five or six children on average in many regions, global fertility is now close to 2.3 children per woman and continuing to fall in many places. Second, improvements in health and longevity mean more people survive to older ages, so population momentum (the built-in tendency of a population to keep growing as large cohorts pass through reproductive ages) still produces growth even as family sizes shrink. Combined, these trends create a world that grows more slowly, ages, and becomes more uneven in where growth occurs.
A closer look at the projections: 2050, 2100 and the idea of a population peak
The UN’s 2024 revision remains the most widely used baseline. It suggests the global population will continue growing through the middle of the century and is likely to peak sometime during the late 2060s to the 2080s under its median assumptions. In plain language: expect around another two billion people by mid-century, but the size and timing of the eventual peak - and whether the population declines or plateaus afterwards - depend heavily on fertility trends in a relatively small group of countries. Some alternative studies, which assume more rapid reductions in fertility thanks to changes in education, contraception and health, produce much lower totals by 2100. Others that assume slower fertility decline produce totals higher than the UN’s median. That range - from perhaps under 9 billion to above 11 billion by 2100 — is what makes population projections both powerful and uncertain.
Put the numbers into classroom terms. If you are studying how population links to development, urbanisation and resources, the 2050 figure matters because it is close enough that the policies and social changes of today will largely determine outcomes. The 2100 figures are useful for thinking about very long-term consequences - climate, land use and economic structures - but remember they are conditional projections, not predictions.
Where growth will (and won’t) happen: regional differences
Not all parts of the world contribute equally to future growth. Much of the increase between now and 2050 will be concentrated in sub-Saharan Africa and parts of South Asia. Countries with high fertility rates and relatively young age structures such as Nigeria, the Democratic Republic of Congo, Pakistan and a handful of other nations - are projected to add the most people in coming decades. In contrast, East Asia (notably China) and much of Europe are already experiencing low fertility and, in some cases, shrinking populations. Because of those regional contrasts, the global picture is one of both big-city expansion in some countries and population contraction in others.
This uneven geography has concrete consequences. Countries with expanding populations will need major investment in schools, jobs and infrastructure or risk very large cohorts of young people becoming unemployed or under-employed. Countries with falling populations face different challenges: ageing workforces, higher pension costs and possible labour shortages unless balanced by migration or productivity increases. That difference helps explain why population policy is not ‘one size fits all’ and why migration and urban policy sit at the centre of so many national debates.
The demographic transition and ageing populations
The concept of the demographic transition helps to make sense of modern population change. Countries typically move from a regime of high birth and death rates to one of low birth and death rates as they develop. That transition brings a temporary ‘bonus’, a large working-age population relative to dependants, which can boost economic growth if labour and investment opportunities exist. But once fertility falls below the replacement level (roughly 2.1 children per woman), ageing and population decline become possibilities unless offset by migration.
Across much of Europe, East Asia and parts of Latin America the fertility rate is already below replacement, meaning these regions face rapid population ageing. The number of people aged 65 and over is rising fast worldwide, even in some lower-income countries, because of longer life expectancy. By mid-century, many countries will look very different demographically: older, smaller families, and often more urban. For cities and planners, that means thinking differently about housing types, transport and services so they meet the needs of older residents as well as younger ones.
Urbanisation, megacities and spatial change
Population trends are not just numbers on a chart, they reshape where people live. The world has moved decisively towards urban living: over half of humanity already lives in cities, a share that will rise further by 2050. That growth feeds the rise of megacities (urban areas with more than 10 million people), mostly in Asia and Africa, and it concentrates resources, economic activity and, sometimes, vulnerabilities. Urban growth can foster innovation and growth, but rapid unplanned expansion can also create sprawling informal settlements, pressure on water and sanitation, and heightened exposure to hazards such as floods and heatwaves.
Migration: the balancing force
Migration reshuffles population between countries and regions and helps to cushion some of the economic strains that ageing or shrinking populations create. Many high-income countries rely on migration to sustain their labour forces and to offset low birth rates. However, migration does not solve the very different challenges of countries with youthful, growing populations: simply moving people does not automatically create jobs or public services in source countries. Migration is also politically charged and shaped by policy, geography and global inequalities, so its role in future population trends will be as much political as demographic.
Health, education and the ‘what if’ scenarios
Population futures are not pre-written; they depend on policies and social changes. Two of the most powerful levers are education (especially for girls) and access to reproductive health and family planning. If countries with high fertility see fast improvements in girls’ education and in access to contraception and maternal health, fertility can fall faster than in baseline projections and that, in turn, reduces long-term population size. Some alternative models, which assume rapid gains in those areas, project a considerably smaller global population by 2100 than the UN’s median. Those scenarios are useful to study: they show how investment in education and health can change the planet’s demographic and environmental trajectory.
Environmental, economic and social implications
Whether the world reaches 9.6 billion or 11.2 billion by 2100 matters for resource use, climate policy and inequality. A larger population increases demand for food, energy and land, but the way those needs are met depends on technology, consumption patterns and political choices. Richer countries tend to have much higher per-person resource use; therefore, population change interacts with patterns of wealth and consumption to determine environmental impact. Economically, a well-managed transition from youthful to older societies can be an advantage (the demographic dividend), but it demands investment in education, health and jobs. Socially, changing age structures can alter family forms, intergenerational relationships and social policy priorities.
Key uncertainties and why demographers disagree
You’ll notice that different reputable sources sometimes give different long-run totals. Why? The dominant source of uncertainty is future fertility in the countries that still have high birth rates — many of them in sub-Saharan Africa. Small differences in how quickly fertility falls translate into very large long-term differences because of two compounding effects: the size of the cohorts that reproduce and the number of reproductive years available across large populations. Other sources of uncertainty include mortality (especially if new health crises arise), future migration patterns, and policy changes that affect family size or labour mobility. That’s why projections are best treated as scenarios that help us think about possibilities, not precise forecasts.
The trend in a nutshell
The world is still growing, but the pace has slowed and the geography of growth has shifted. Expect roughly 9.6–9.8 billion people by 2050 under the UN’s medium scenario, and a range of possible outcomes by 2100 that depend mainly on how rapidly fertility falls in a handful of high-fertility countries. Populations will age, cities will grow, and migration will remain a central feature of how regions balance labour and demographic pressures. These are not abstract trends, they shape the places you live in, the jobs you might do, and the environmental challenges humanity faces. Look at the numbers critically, and always ask which assumptions lie behind a projection.
Sources and further reading
United Nations, Department of Economic and Social Affairs, Population Division, World Population Prospects 2024: Summary of Results (2024). World Population Prospects
United Nations press release: World population projected to reach 9.8 billion in 2050, and 11.2 billion by 2100 (UN DESA). United Nations
Our World in Data — Explainer and charts on the UN 2024 population revision (Ritchie, Our World in Data, 2024). Our World in Data+1
Our World in Data — population datasets and long-run charts. Our World in Data
Gu, D. et al., Major Trends in Population Growth Around the World (review article on demographic transitions and ageing). PMC/NCBI. PMC
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