How does urbanization lead to population growth

Immigration, Displacement and Asylum: Current Issues

Jochen Oltmer

Dr. phil. habil., born in 1965, is apl. Professor of Modern History and Migration History and member of the board of the Institute for Migration Research and Intercultural Studies (IMIS) at the University of Osnabrück.

More and more people around the world are living in cities. Various factors contribute to this development, including migratory movements. An overview of trends in urbanization in different regions of the world.

Countless cars and people packed together on a street in a very populous part of Lagos, Nigeria. (& copy picture-alliance, AA)

According to the United Nations, in 2007 the number of city dwellers worldwide exceeded those of people who lived in rural areas for the first time. In 2018, 55 percent of the world's population lived in cities - that was around 4.2 billion people. The UN estimates that their number will grow to 6.7 billion by 2050. Then two thirds of the world's population would live in cities. Almost 90 percent of this growth is concentrated in Asia and Africa. [1] This trend is called urbanization - or urbanization.

Why are cities growing?

Different factors contribute to the growth of the urban population. One element is natural growth, which occurs when the number of births in a city is higher than that of deaths. Because the birth rates are usually not very high, especially in the big cities, natural population growth often remains quite low. Migrations from rural areas in the immediate vicinity or further afield, but to a lesser extent also from other countries, can also contribute to urban population growth. It is not uncommon for such country-to-city walks to be more important for the increase in the number of residents than for natural growth. Another, albeit usually less important, factor that leads to a population growth in a city is incorporation: Neighboring communities in a large city that is growing in area lose their independence and are added to it.

The UN surveyed the degree of urbanization of the continents for the last time in 2018. A global comparison shows that the degree of urbanization is lowest in Africa at 42.5 percent and in Asia at 49.9 percent. North America has the highest proportion of the urban population with 82.2 percent, followed by the South America and Caribbean region with 80.7 percent. Europe achieved 74.5 percent, Oceania 68.2 percent. In addition to city states such as Singapore, countries such as Belgium with 98.5 percent and Japan with 91.9 percent as well as individual emirates on the Persian Gulf such as Kuwait (100 percent) and Qatar (99.6 percent) have extremely high degrees of urbanization.

The urban population is growing - worldwide

As the following diagram shows by comparing the continents for 1950, 2018 and 2050, urbanization has increased worldwide since the middle of the 20th century. Especially in the societies of the Global South, the size of the urban population has skyrocketed - a development that is likely to continue.

By 1900, nine out of ten of the world's largest cities were in Europe or the United States. In 1950 only two cities worldwide had more than ten million inhabitants each; in 1990 there were ten such "megacities", which together numbered 153 million people. In 2018 there were already 33 megacities with a total of 529 million inhabitants. These 33 cities, of which 20 were in Asia, six in Latin America, three in Africa, and two each in Europe and North America, housed 13 percent of the world's urban population and 7 percent of the world's population. By 2030, the number of megacities is expected to rise to 43, which will then accommodate almost 15 percent of the world's population.


By far the largest megacity in 2018 was the Tokyo (Japan) metropolitan area with around 37 million inhabitants, followed by Delhi (India) with 29 million, Shanghai (China) with 26 million, and Mexico City and São Paulo (Brazil) with each around 22 million. Since it can be assumed that, due to the current high average age of the Japanese population and the low birth rates, Tokyo's population will decline from 2020, Delhi is likely to replace the Japanese capital as the world's largest city by 2030 with an estimated 39 million people.

The development of "mega-regions", also known as "metacities", is also well advanced. These are urban areas with more than 20 million inhabitants each. They also develop their growth dynamics because individual megacities are merging with one another. In 2010/11, the UN assumed that the Japanese mega-region Tokyo-Nagoya-Osaka-Kyoto-Kobe would comprise around 60 million people in 2015. The distance Tokyo-Kobe is just under 430 kilometers; almost half of the Japanese population lives in this mega-region. In Brazil, the converging belt of large cities from São Paulo to Rio de Janeiro should have around 43 million residents in 2015. And the Chinese mega-region Hong Kong-Shenzhen-Guangzhou is estimated by the UN to have a population of 120 million. [2] More recent information that is directly comparable is not available, but the estimates for 2010/11 certainly show the magnitude of such new urban agglomerations. [3]

Growth especially in the Global South

More than 85 percent of the world's urban population growth is expected to occur in Africa and Asia by 2030. In the Global South, the UN estimates that the urban population will almost double from 3.2 billion in 2018 to 5.6 billion by 2050. How quickly the urban population has grown in the past decades and will continue to grow in the future is illustrated by the following data for the African population: In 1910 the number of urban dwellers in Africa is said to have been four million, in 1950 it was 33 million, in 1990 it was 200 million , In 2018 it was 548 million. According to UN estimates, 824 million people will be living in African cities in 2030 and almost 1.5 billion in 2050. [4] The Nigerian city of Lagos offers an impressive example of the growth of African cities: in 1950 there were around 325,000 people there; today, with a population of around 13.5 million, it is the second largest city on the continent after Cairo. And by 2030, Lagos is expected to have 20.6 million people. Cairo, on the other hand, had a population of almost 2.5 million in 1950, and 25.5 million are expected in 2030. [5] It is currently assumed that from 2033 onwards, more people will live in cities than in rural areas on the African continent.

A large part of the cities and urban agglomerations in Africa, Asia or South America grew unplanned in the past decades. The infrastructure (roads, water supply and sanitation, electricity, garbage disposal, etc.) mostly did not keep pace. Social conflicts and the formation of slums were often the result. Slums can be defined as informal settlements with a high population density, which are characterized by a precarious building fabric, poorly developed infrastructure, little protection from the weather and from intruders (animal and human).

As the cities grow, so do the slums

In 2014 around 881 million people worldwide lived in slums, the UN estimates - that is, almost one in eight people and almost 30 percent of the global urban population. While the absolute numbers have increased since 1990 (around 689 million), they have declined in percentage terms (1990: 46.2 percent). There are also immense differences in the regional distribution: in sub-Saharan Africa in particular, more than half of the city dwellers were slum-dwellers, in the cities of South Asia it was almost a third. [6] One of the largest slums in the world, Nezahualcóyotl, part of Mexico City, is home to around 1.2 million people. Together with other neighboring settlements, the district is also known as the "mega-slum".

Even if they are characterized by large slums, (large) cities still remain attractive immigration destinations for many people: They are centers of economic growth, economic and social innovation and, compared to rural regions, usually offer more numerous and differentiated employment opportunities in the formal and informal sector . Health care is usually better, and this also applies to the supply of daily necessities or educational opportunities. [7] Overall, immigration to the city appears to many people as an opportunity to open up more opportunities for action. In addition to natural population growth, urban growth in the future will therefore continue to be largely the result of rural-urban migration. [8th]