Over the past century the population of Africa has grown exponentially. In 1950, the total population of Africa was no higher than 224 million while today it just crossed 1 billion.

Another major problem affecting the demographics of Africa is the fact that the continent has the lowest life expectancy in the entire world. In most African countries people die on average before they reach the age of 50. Only the Northern rim of the continent, being the countries that border the Mediterranean Sea, reaches a life expectancy of 70 and higher. 

The combination of a high fertility and a low life expectancy results in a very young population.

Nevertheless Africa keeps on growing, and it does so on an unprecedented scale. According to the United Nations Population Division, at the height of the population boom (during the early eighties, before the disastrous effects of HIV became one of the major brakes on demographic growth), annual growth rates reached as high as 2.89%, which would have resulted in a doubling of the African population in less than 25 years' time. The current growth rate is lower, about 2.25%, but still far higher than the global equivalent of 1.09% (the European growth rate is even negative: -0.02%).

Since the eighties, life expectancy has fallen dramatically in these selected hard-hit African countries. The reason for this drop is the rise of HIV/AIDS. Today, in Botswana, Zimbabwe and Swaziland more than 30% of the population has been infected with HIV.
Source: Wikimedia Commons

Life expectancy of the world (2009 estimates by CIA). The African continent jumps out with its low life expectancy. - Source: Wikipedia 

Most African countries have annual population growth rates above 2% (2009 estimates by CIA) - Source: Wikipedia

Urbanization, a new trend

The urbanization of the world occurs in an unprecedented pace. Each week the urban regions gain one million new inhabitants - about 180,000 per day. A growth which is irreversible, according to the UN. Today almost 3.3 billion people live in urban areas. By 2030, according to the predictions of the UNDP as much as 5 billion people will be living in cities. That is about 60% of all world citizens.

Urbanization in Africa

Although it is still one of the least urbanized continents in the world, urbanization takes place faster in Africa than in any other continent. It is estimated that between 2000 and 2030 the number of people in Africa living in a city will rise from 294 million to 742 million.

The great wave of urbanization, which is taking place in the third world now, is radically different from the western urbanisation that started in the second half of the eighteenth century. The growth is much more massive and much faster. The exodus from the countryside has other causes than the Western urbanization, which was inspired by the Industrial Revolution in the eighteenth century. In developing countries, many people are driven to the city because of war and insecurity, failed harvests and climate change such as drought and floods.

Millions of people in Africa are on the run, for a variety of reasons. Many of these end up in refugee camps or informal settlements, some manage to flee the continent and arrive in Europe, but many others seek refuge in the big cities of the continent. They often end up in the suburban slums, on the edge of society.

Cairo, the biggest city of the continent, is a good illustration of this urban growth. During the twentieth century the city expended explosively. On the image on the left the edge of the city in 1965 (yellow) and 2008 (red) is visualized: over those 33 years the number of inhabitants increased from 5 to 12 million. Almost half of them are living in slums, the result of a year's long lack of money and regulation combined with strong population growth.

More to the south the situation is sometimes even worse: 72% of the urban population south of the Sahara live in slums, and that number is rapidly increasing, with 4.53% per year the highest of all continents.

Kibera, for example, is one of the biggest sub-Saharan slums. At the edge of Nairobi, it counts over a million inhabitants, with an estimated population density of a staggering 200,000 to 300,000 people per square kilometer.

Because of the many wars and the devastating impact of the tsunami in 2004, Somalia leads the list of African countries by as much as 97% of the urban population living in slums. Other countries do much better: according to the same figures only 3.4% of the urban population in Zimbabwe would be living in slums.

With the current trends of population growth and urbanisation, Africa is heading towards an unprecedented urban crisis and must face up to new economic, social, and environmental problems.

Sources

Kibera: Africa’s largest slum - Affordable Housing institute
Managing rapid urbanization in Africa: Some aspects of policy - Journal of Third World Studies
State of World Population 2008 - UNFPA
UNDERSTANDING SLUMS: Case Studies for the Global Report 2003 - UN Development Planning Unit 
UN Population Division- World Population Prospects
Urbanization in Africa - The encyclopedia of Earth