Exploring Population Growth Patterns in Key Countries

Population growth is rarely uniform. While some countries are adding millions every year, others are shrinking. Behind every number lies a story of fertility, migration, mortality, and policy choices that shape how nations grow, age, and adapt. Understanding these patterns is essential to grasp the future of food systems, labour markets, climate goals, and social welfare across the world.

The global picture of population growth 🔗

According to the United Nations World Population Prospects 2024, the world had around 8.2 billion people in 2024 and is projected to peak at roughly 10.3 billion in the mid-2080s before gradually declining to 10.2 billion by 2100. This is a major shift from earlier forecasts, which assumed the global population would keep rising throughout the century.

The slowdown is being driven mainly by a sharp fall in fertility rates. The global average fertility rate is now around 2.3 children per woman, down from more than 5 in the 1960s. Yet the pace of change varies enormously between regions, and that variation is what makes the population story so layered.

Where growth is concentrated 🔗

Asia and Africa account for almost all of the world’s current population increase. More than half of the projected rise in global population through 2050 will come from just eight countries: India, Nigeria, Pakistan, the Democratic Republic of the Congo, Ethiopia, Tanzania, Egypt, and Indonesia. Sub-Saharan Africa, in particular, is expected to keep growing well into the second half of the century because of persistently high fertility rates and a very young population structure.

In contrast, Europe and East Asia are seeing the opposite trend. Countries such as China, Japan, South Korea, Italy, and Germany have populations that have already peaked and are now declining. In 2024, 61 countries were experiencing population shrinkage, mostly due to low fertility combined with limited or negative net migration.

Factors influencing population growth 🔗

Population growth is determined by the interaction of four core demographic components: fertility, mortality, migration, and population momentum. The first three are direct drivers. The fourth is more subtle but equally powerful.

Fertility 🔗

Fertility refers to the number of children a woman has on average during her reproductive years. A Total Fertility Rate (TFR) of about 2.1 is considered the replacement level, meaning the level at which a population would remain stable in the long run without migration. Today, more than half of all countries have a TFR below 2.1, which means their populations would eventually decline without migration.

Mortality 🔗

Falling mortality and rising life expectancy add to population growth even when birth rates drop. Global life expectancy at birth reached 73.3 years in 2024, an increase of more than 8 years since 1995, and is projected to climb to around 77.4 years by 2054. As more people live longer, populations grow older and the share of elderly citizens rises rapidly.

Migration 🔗

Migration redistributes people across borders. For countries with low fertility, migration can be the difference between gradual decline and continued growth. The United States, Australia, Canada, and several European nations rely heavily on immigration to sustain workforce size and economic output.

Population momentum 🔗

Even when fertility falls to replacement level, a population with many young people will keep growing for decades simply because a large cohort is still entering reproductive age. The UN estimates that population momentum from today’s youthful age structure will account for 79 per cent of the global population increase through 2054, adding about 1.4 billion people. This is why India’s population continues to rise even though its fertility rate has dropped below replacement.

India: the world’s most populous country 🔗

According to UN estimates, India surpassed China as the world’s most populous country in April 2023, when its population reached approximately 1.426 billion. India is expected to continue growing for several more decades, with projections suggesting the population could peak at around 1.7 billion by the 2060s before slowly declining.

What makes India’s case fascinating is that this growth is happening even as fertility falls. The UNFPA notes that India’s TFR is now 2.0, slightly below the replacement level of 2.1. Most southern and western states, including Kerala, Tamil Nadu, Karnataka, Andhra Pradesh, and Maharashtra, have fertility well below replacement, while northern states such as Bihar, Uttar Pradesh, Jharkhand, and Madhya Pradesh still report higher rates.

This divergence creates a layered demographic picture. The fertility rate in Sikkim has dropped to 1.1, while Bihar remains well above 3. The state of Andhra Pradesh recently rolled back a long-standing policy that disqualified people with more than two children from contesting local elections, signalling a shift in concern from overpopulation to under-replacement fertility in some regions.

India’s growth is now driven mainly by population momentum rather than high birth rates. A youthful population means around 65 per cent of Indians are below 35, providing a potential demographic dividend if enough jobs and skills are created. By 2030, roughly one in five working-age people in the world is projected to be Indian.

China: from rapid growth to decline 🔗

China’s trajectory is a striking contrast. After decades of rapid expansion, China’s population peaked at 1.426 billion in 2022 and has begun to fall. Projections suggest the country could lose more than half its population by 2100, dropping to around 633 million.

The reason lies in China’s earlier and steeper fertility decline, driven by the one-child policy introduced in 1979 along with rapid urbanisation, rising education levels, and changing social norms. Even after the policy was relaxed and finally replaced with a three-child policy, birth rates have continued to fall. China’s current TFR is roughly 1.0, far below replacement, and the country is now ageing faster than almost any other large economy.

Australia and New Zealand: slow, migration-driven growth 🔗

Australia and New Zealand sit at the opposite end of the spectrum from sub-Saharan Africa. Both countries have low fertility rates and rely heavily on migration to maintain population growth. Australia’s TFR fell to 1.48 in 2024, the lowest on record, while New Zealand sits at a similar level.

Despite this low fertility, Australia’s population crossed 27.5 million in 2025 and is forecast to reach 31.5 million by 2035-36. According to the 2025 Population Statement from Australia’s Centre for Population, net overseas migration in 2024-25 was about 306,000 people, making it the dominant driver of growth. The annual growth rate is expected to ease from a recent peak of 2.5 per cent to about 1.2 per cent over the coming decade.

New Zealand shows a similar pattern. Migration has played a defining role in shaping its demographic composition, with Asian, Pasifika, and Middle Eastern communities driving much of the recent population growth. Both countries face the classic challenge of low-fertility, high-income nations: how to sustain workforce numbers, fund pensions, and support an ageing population without overreliance on immigration.

The role of fertility and migration in future growth 🔗

Looking ahead, the world is splitting into roughly three demographic groups based on the timing of their population peak.

Countries that have already peaked 🔗

About 63 countries with 28 per cent of the world’s population have already passed their peak. This group includes China, Japan, Germany, Italy, Spain, Russia, South Korea, and Thailand. For these countries, the main challenges are ageing, shrinking workforces, and rising health and pension costs. Policy responses range from pro-natalist incentives such as cash benefits and parental leave to easier immigration pathways for skilled workers.

Countries peaking between 2025 and 2054 🔗

Around 48 countries with about 10 per cent of the world’s population are expected to peak within the next three decades. This group includes Brazil, Indonesia, Iran, Türkiye, Argentina, and the Netherlands. These countries are still growing but are nearing the turning point of their demographic transition.

Countries that will keep growing 🔗

The remaining 126 countries, including India, Pakistan, Nigeria, Indonesia, the United States, and the Democratic Republic of the Congo, are projected to continue growing well past 2054. Many high-fertility African nations such as Niger, Somalia, and Angola will see the fastest growth, raising urgent questions about food security, education capacity, employment, and climate vulnerability.

Why these patterns matter 🔗

Population dynamics shape almost every public policy question. High-growth countries need to invest in schools, jobs, healthcare, and housing while protecting natural resources. Low-growth and shrinking nations must rethink retirement ages, immigration systems, productivity, and care economies. India’s situation is particularly delicate because the country must get richer before it gets older, creating jobs for millions entering the workforce while also preparing for an elderly population that is expected to more than double by 2050.

Government interventions, from family planning programmes to migration rules, do influence these trajectories, but the deeper drivers are usually social: women’s education, urbanisation, access to contraception, economic opportunity, and changing aspirations within families. Policies that work with these forces, rather than against them, tend to be the most effective.

What do you think? If your home state continues on its current fertility path, what kind of demographic future do you see in the next 30 years? And how should countries balance the rights and choices of individuals with the longer-term needs of a sustainable population structure?

References

1. https://www.un.org/development/desa/pd/content/world-population-prospects-2024-summary-results-0
2. https://ourworldindata.org/un-population-2024-revision
3. https://www.ined.fr/en/everything_about_population/demographic-facts-sheets/focus-on/2024-les-nations-unies-publient-de-nouvelles-projections-de-population-mondiale
4. https://reliefweb.int/report/world/world-population-prospects-2024-summary-results
5. https://population.un.org/wpp/assets/Files/WPP2024_Summary-of-Results.pdf
6. https://www.un.org/en/desa/india-overtake-china-world-most-populous-country-april-2023-united-nations-projects
7. https://india.unfpa.org/en/publications/indias-population-growth-and-policy-implications
8. https://www.lowyinstitute.org/the-interpreter/population-paradox-india
9. https://populationconnection.org/blog/new-un-population-projections-where-are-we-headed/
10. https://www.deloitte.com/au/en/services/economics/blogs/baby-blues-australia-becomes-more-reliant-migration.html
11. https://population.gov.au/sites/population.gov.au/files/2026-03/population-statement-2025.pdf