Global urbanisation

Urbanisation is the growth in the share of people living in towns and cities.

The United Nations' World Urbanization Prospects 2025 found that:

• in 1950, 20% of the world's 2.5 billion people lived in cities;
• by 2025, 45% of the world's 8.2 billion people did: more than double the share;
• another 36% live in towns, and only 19% in rural areas;
• two-thirds of the world's population growth between now and 2050 is expected to be in cities.

The UN now counts a city as a place with at least 50,000 people, packed at least 1,500 to a square kilometre.

Urbanisation has happened at different times and speeds:

• HICs urbanised early, with industry. By 1957, more of their people lived in cities than in the countryside. Their city populations now grow slowly.
• NEEs, such as China, India and Brazil, have urbanised fast in recent decades: between 2000 and 2025, they were among the countries adding most people to cities.
• LICs started later: in 1950, only 8% of their people lived in cities. They are now urbanising fastest, and the UN expects 40% of their people to live in cities by 2050.

Seven countries, including India, Nigeria and Pakistan, are expected to add over 500 million city residents by 2050.

Rural-urban migration is people moving from the countryside to cities, for a mix of reasons:

Natural increase adds to this: many migrants are young adults, so cities have many births and relatively few deaths.

A megacity is a city of 10 million people or more. According to the UN:

• there were 8 in 1975, and 33 in 2025;
• 19 of them are in Asia, 5 in Latin America, 4 in Africa, 3 in Europe and 2 in Northern America;
• the largest is Jakarta, with nearly 42 million people, then Dhaka, with almost 37 million, and Tokyo, with 33 million;
• by 2050, there should be 37, and Dhaka will probably be the largest.

Most megacities are now in the global South, in NEEs and LICs, where they are growing fast. Tokyo, in an HIC, is expected to shrink.