Urban Growth in Africa

Taking a look on how Africa´s cities took growth

For most time within human history, living in rural areas was quite the usual scenario. A century ago, only about five percent of the world people were living in urban areas. While some cities like London grew early, these were an exception to the norm of rural living conditions. Suddently, within a short interval of time, urbanization took place. By 1900 one out of ten persons was living in an urban area. Today every second does: tendency increasing, especially in less developed countries. Within this short piece, we cover the process of urban growth in Africa how it differs from an overall trend.

Here, an open dataset provided by Africapolis is analyzed. It maps urban agglomerations on the African continent and their population development from 1950 until 2015. To the right, all of these agglomerations are displayed which are mapped within the dataset, roughly 90000. A special geographic characteristics to be recognized is the coastal-heavy distribution of urban spaces. Not only for the sea, water bodies in general such as the Nile, initially provided best locations to develop settlement structures. In a similar sense, the Saharan-conditions or general climate/soil-conditions situated country-inwards reduced chances of settlement development.

The 93.278 captured urban gatherings within the dataset follow a 'power-law-distribution': few cities with very many inhabitants, many more with lower population numbers. Here, we focus on those with more than a million inhabitants which we frame as megacities (even though the formal definition of a megacity for applies a minimum of ten million people).

By 1950, only two cities in Africa reached a million citizens: Alexandria and Cairo. None in sub-Saharan Africa. As time went on, the continent observed a steep incline in the number of megacities. As by 2015, we count 74.

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Africa´s current mega-cities historic development

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For the 74 megacities of 2015, the development of each is tracked within the graphic to the right. While Cairo is excluded from the visualization (as it´ a population size exceeds a reasonable scale), we see most cities crossing the threshold of a million people between 1980 and 2000. At latest in 2000, all cities crossed the magic bar.
Over time, different scientific theories arose on the reasons of urbanization. The classic economic theory goes that with increased employment opportunities in cities, people are more likely to stick around. Thus, linking economic growth and urbanization. In the initial theory, people were assumed to make rational decisions on moving to cities for employment. At some point, growth of cities could not be explained anymore by only accounting for rationally motivated search for employment. Thus, theory shifted the perspective on human decision-making on migrating to cities. Now, decisions were theorized to be based on the believe to find employment (where there were actually significantly fewer opportunities available than people moving to cities). Recent decades of research provided an increasing integration of social factors to the reasoning of urban growth. Most recently, for example, climate change and wars are discussed to influence the migration to urban spaces.

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Urbanization on the African continent is different to this process in other parts of the globe in terms of both the timing and magnitude. Here, the theoreized link of economic growth and urbanization does not hold as the entire continent aggegates to a GDP growth of -0.1 percent between 1975 and 2005 (Fox, 2012) Still, the level of urban growth within that period surpassed other global regions showcasing significantly stronger economic growth. "Urbanization without growth",as described by Fay and Opal (2000) rather suits the African urbanization process.

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Following the argument by social scientist Sean Fox, two important factors are responsible for urban growth. First, a decrease in death rates in general, even more salient in urban areas. Historically, there has always been a migration towards cities. During times of high fatality rates though, cities remained a "demographic sink" even while experiencing migration, thus unable to grow larger. Seconnd, he ability to provide more densely populated areas with food. Fox describes, especially from the post-colonial era, technology, institutions, and international aid and assistance decreased fatality rates and enabled supply of food.
Taking a look to the future, the impacts of climate change are thought of to significantly foster migration towards African cities. Where conditions to practice agriculture are more and more threatened, people will seek employment and livelihood security within the city.

Africa´s 10 biggest cities by 2015 (according to Africapolis)

Editors note: We are currently working on an interactive version to let you explore the urban growth dataset. Find the source code here.

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