World’s Cities at a Glance
Cities have emerged as the dominant form of human settlement, and they are major economic and environmental actors. The data that follow give a sense of cities as a global phenomenon and of their place in human civilization in the twenty-first century.
Since 1950, the global urban population has increased by roughly a factor of five, from 0.7 billion in 1950 to 3.9 billion in 2014. It is expected to increase by another 60 percent by 2050, when 6.3 billion people are projected to live in urban settlements.1
As of 2009, more than half of the world’s people live in cities, and the urbanization trend is continuing. More than 90 percent of urban growth is happening in developing countries, although not all developing regions are majority-urban yet. By 2040, all world regions, including Africa, will be majority-urban.2
Urban growth rates are stable or slow in highly urbanized regions such as Europe, Latin America, and Oceania, but Asia and Africa are urbanizing quickly. The fastest urban growth is in Africa, where growth rates in some countries exceed 5 percent per year. Europe has the world’s lowest urban growth—in some Eastern European countries, rates are actually negative.3
Over the past 65 years, the number of “megacities”—cities with 10 million or more inhabitants—has grown more than 14-fold, from 2 in 1950 to 29 in 2015. By 2030, the world is projected to have 41 megacities. But most urbanites—nearly half of the global total—live in cities of fewer than 500,000 people. The number of cities with more than 500,000 people has grown nearly sixfold since 1950, from 304 to 1,729.4
The Built Environment
The built-up land of cities covers 1–3 percent of global land area, but this could grow to 4–5 percent by 2050 as urban areas expand outward, primarily into prime agricultural land.5
Cities are becoming less dense: for decades, across all world regions, the urban land area has expanded faster than the population. If average densities continue to decline, the built-up areas of developing-country cities will increase threefold by 2030 while their populations double. Industrialized-country cities are projected to expand 150 percent while their populations increase by 20 percent. An estimated 60 percent of the built environment needed to accommodate the earth’s urban population by 2050 is not yet built.6
Household sizes are falling in many countries, which is contributing to an increase in the number of dwellings and the resources required to build them. By 2025, the growth in the number of households is projected to be 2.3 times the population growth rate in the world’s top cities. The construction industry is a major consumer of resources, including 40 percent of all water, 70 percent of timber products, and 45 percent of energy.7
By one estimate, cities will need to double their annual investment in physical capital to $20 trillion annually by 2025, most of this in emerging economies.8
Cities are economic engines: some 80 percent of the global gross domestic product (GDP) is produced in cities, and 60 percent is produced in the 600 most productive cities, where one-fifth of the world’s population now lives. Urban economic activity accounts for up to 55 percent of gross national product (GNP) in low-income countries, 73 percent in middle-income countries, and 85 percent in high-income countries. Cities generate a disproportionate amount of revenue for governments.9
Urban areas account for a high share of global consumption, including 60–80 percent of energy consumption and more than 75 percent of natural resource consumption. They account for 75 percent of the world’s carbon emissions.10
Economic power is increasing in cities in emerging economies. By 2025, many of the cities that currently are in the world’s wealthiest countries will not even make the list of the 600 richest cities (in terms of GDP) as new cities—in China, the Democratic Republic of the Congo, Nigeria, Indonesia, Pakistan, and India, among other countries—displace them.11
An estimated 1 billion people will become part of the global “consuming class” by 2025. They are expected to inject $20 trillion of additional spending annually into the global economy.12
Consumption in the lowest-and highest-consuming megacities differs by a factor of 28 in energy per capita, a factor of 23 in water per capita, a factor of 19 in waste production per capita, a factor of 35 in total steel consumption, and a factor of 6 in total cement consumption. Ten percent of the urban population of developing countries lacks access to electricity, and 18 percent uses wood, dung, or charcoal for cooking. The figures are much higher for urban populations in the least-developed countries.13
Poverty, Sanitation, and Health
Although cities are economic engines, they also can be centers of poverty. Approximately 1 in 7 people in urban areas live in poverty, mostly in informal settlements of the developing world. An estimated 863 million urban residents were living in slum conditions in 2012, up from 650 million in 1990. Yet the overall share of urban populations living in slums fell over this period, from 46 percent to 33 percent.14
Less than 35 percent of cities in developing countries treat their wastewater. About 500 million urban dwellers worldwide share sanitation facilities with other households. More than 170 million urban residents lack access to even the simplest latrine and have no choice but to eliminate their waste in the open.15
Some 1.5 billion urban dwellers face levels of outdoor air pollution that exceed the maximum recommended limits. In 2012, outdoor air pollution killed an estimated 7 million people, representing 1 in 8 deaths globally and making air pollution the largest single environmental health risk. Meanwhile, indoor air pollution (from the burning of solid fuels for cooking) killed an estimated 4 million people in 2014.16
Gary Gardner is director of publications at the Worldwatch Institute and co-director of the State of the World project.
Read more in State of the World: Can a City Be Sustainable?