Four-fifths of the world’s population now live in urban areas

More than 80 per cent of people worldwide now live in towns and cities, according to a major United Nations report, and this figure is set to rise further, underscoring the need to ensure urban areas benefit both our health and the planet.

The most recent edition of the World Urbanisation Prospects report, published in 2018, found that 55 per cent of people live in urban areas, but that estimate relied on countries’ widely varying definitions of what constitutes an urban or rural settlement. For instance, Denmark defines urban areas as those inhabited by as few as 200 people, but this figure is 50,000 in Japan, muddying our view of urbanisation globally.

To gain a clearer picture, Sara Hertog at the UN in New York and her colleagues defined urban areas as either cities inhabited by at least 50,000 people, with at least 1500 individuals per square kilometre, or towns with at least 5000 inhabitants and a density of at least 300 people per km². They classed the remaining areas as rural. “We used the same definition for all countries for the first time,” says Hertog.

Next, the researchers analysed satellite and national survey data from 237 countries and regions to estimate the degree of urbanisation worldwide in 2025. This revealed that 45 per cent of the world’s population now live in cities, mostly in those with fewer than 250,000 people, while 36 per cent live in towns – meaning 81 per cent of people are urban-dwellers. The remaining 19 per cent live in rural regions.

Using a statistical model that accounted for factors like population ageing and migration trends, the team also estimated that by 2050, 83 per cent of people worldwide will live in urban, rather than rural, regions. The actual number – rather than proportion – of people living in both towns and cities is set to rise until 2050, while the number of rural inhabitants is predicted to peak in the 2040s – mostly driven by the Democratic Republic of the Congo – before declining until 2050, says Hertog.

The fresh estimates will help the UN assess progress towards its 11th sustainable development goal, which aims to “make cities and human settlements inclusive, safe, resilient and sustainable” by 2030, says Hertog. The results will also help shape policies to reduce global warming by feeding into reports produced by the Intergovernmental Panel on Climate Change, she says.

The drivers of urban population growth vary between regions. In eastern and southern Asia, it’s mainly driven by people migrating from rural to urban areas within countries, says Hertog. “People move in search of education and employment, but also social life,” she says. In Europe and North America, international migration plays a large role, while in sub-Saharan Africa, it’s mainly down to birth rates exceeding deaths, she says.

Increasing urbanisation can either benefit or harm the environment. For instance, if a city expands its borders due to population growth, but public transport links are not planned appropriately, this can lead to urban sprawl, where people rely heavily on cars – increasing carbon emissions, says Hertog. On the other hand, careful planning can provide transportation that is more energy-efficient than what is available in rural regions, she says.

Urbanisation also has health effects. For instance, people are generally more exposed to air pollution and extreme heat in cities, both of which have been linked to worse cardiovascular health and seem to raise the risk of conditions like Alzheimer’s disease, says Andrea Mechelli at King’s College London. What’s more, a lack of green space in some urban areas is linked to increased anxiety and depression, he says.

But urbanisation can also bring health benefits. “Healthcare is more responsive; it’s more comprehensive in cities compared to rural areas,” says Mechelli. “There are also many social advantages – you’re more likely to connect with someone who shares the same values as you than in rural areas, where you might need to drive 2 hours to find someone who shares the same interests,” he says.

It’s not that we should reverse urbanisation, or people shouldn’t live in cities, says Mechelli. “The report tells us it’s now more urgent than ever to think about how to make our cities more liveable, and this means greener – with all the benefits that brings.”