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

According to a major United Nations report, more than 80 percent of people worldwide now live in cities and towns, and this figure will continue to rise, highlighting the need to ensure that urban areas benefit both our health and the planet.

Latest issue of the magazine Prospects for global urbanization report, published in 2018, found that 55 percent people live in urban areas, but this assessment was based on widely varying countries' definitions of what constitutes an urban or rural settlement. For example, in Denmark, urban areas are defined as areas containing as few as 200 people, but in Japan the figure is 50,000, distorting our understanding of global urbanization.

To get a clearer picture, Sarah Hertog at the UN in New York and its colleagues defined urban areas as cities with a population of at least 50,000 people, with a population density of at least 1,500 people per square kilometer, or cities with a population of at least 5,000 people and a population density of at least 300 people per km.². They classified the remaining areas as rural. “This is the first time we have used the same definition for all countries,” says Hertog.

The researchers then analyzed satellite and national survey data from 237 countries and regions to estimate the degree of urbanization worldwide in 2025. It showed that 45 percent of the world's population now lives in cities, mostly in cities with populations of less than 250,000 people, and 36 percent live in cities, meaning 81 percent of people are city dwellers. The remaining 19 percent live in rural areas.

Using a statistical model that takes into account factors such as aging populations and migration trends, the team also estimated that by 2050, 83 percent of people worldwide will live in urban rather than rural regions. The actual number, not the proportion, of people living in both towns and cities will rise until 2050, while the number of rural residents is projected to peak in the 2040s (largely driven by the Democratic Republic of Congo) and then begin to decline until 2050, Hertog says.

The latest assessments will help the UN assess progress towards its goal. Sustainable Development Goal 11which aims to “make cities and communities inclusive, safe, resilient and sustainable” by 2030, Hertog says. The results will also help shape policies to reduce global warming by being included in reports prepared by the Intergovernmental Panel on Climate Change, she said.

The drivers of urban population growth vary by region. In east and south Asia, this is mainly due to people migrating from rural to urban areas within the country, Hertog said. “People move for education and work, and for a social life,” she says. In Europe and North America, international migration plays a big role, while in sub-Saharan Africa it is mainly due to birth rates exceeding deaths, she said.

Increasing urbanization can benefit or harm the environment. For example, if a city expands its boundaries due to population growth, but public transportation routes are not planned properly, it can lead to urban sprawl where people rely heavily on cars, leading to increased carbon emissions, Hertog says. On the other hand, careful planning can provide more energy-efficient transport than is available in rural areas, she says.

Urbanization also has health consequences. For example, in cities, people tend to be more exposed to air pollution and extreme heat, both of which are associated with worsening cardiovascular health And appear to increase the risk of diseases such as Alzheimer's diseasespeaks Andrea Mechelli at King's College London. Moreover, the lack of green space in some urban areas is due to increased anxiety And depressionhe says.

But urbanization can also bring health benefits. “Healthcare is more responsive; it’s more comprehensive in cities compared to rural areas,” says Mechelli. “There are also a lot of social benefits here: you're more likely to connect with someone who shares the same values ​​as you than in rural areas, where you might have to drive two hours to find someone who shares the same interests,” he says.

“It's not that we should reverse urbanization or that people shouldn't live in cities,” says Mechelli. “The report says it is now more important than ever to think about how to make our cities more liveable, and that means greener – with all the benefits that entails.”