West African Urbanisation Trends
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N°01 SAHEL AND WEST AFRICA Club JUNE 2011 Secretariat Secrétariat du WEST DU SAHEL ET DE AFRICAN Club L'AFRIQUE DE L'OU EST FUTURES SETTLEMENT, MARKET AND FOOD SECURITY by LÉONIDAS HITIMANA, PHILIPP HEINRIGS, MARIE TRÉMOLIÈRES (SWAC Secretariat), based on a contribution of Michel Arnaud WEST AFRICAN URBANISATION TRENDS A coherent and reliable West Africa has been experiencing intensive urbanisation 1 retrospective of urbanisation for more than fi fty years. This urbanisation has affected the region’s largest towns and small urban centres alike. The Larger towns and average distance between agglomerations has declined from 2 more towns 111 km to 33 km. However, urbanisation rates vary widely across countries. They are highest in coastal countries that have not Choosing a numerical defi nition been threatened by major socio-political crises. The fi ndings in 3 of urban population the Africapolis study 1, compared to the United Nations data, raise some interesting questions such as: Why has Nigeria’s Large differences in urbanisation rate changed so little? Is the slowdown in the rate 4 urbanisation rates of urbanisation since 1980 structural or cyclical? 1 “Africapolis Urbanisation Trends 1950–2020 – a geostatistical approach – West Africa study”, Why has Nigeria’s urbanisation Paris, 2009. The Africapolis study was supported by AFD and co-ordinated by researchers at 5 rate changed so little? CNRS and Paris Diderot University. The report can be downloaded from: http://www.afd.fr Is the slowdown in the 6 urbanisation rate structural? Varied stages of evolution in 7 the region’s urban systems The opinions and interpretations expressed in this paper do not necessarily reflect the views of the OECD or the SWAC Secretariat. ORIGINAL VERSION: FRENCH A COHERENT AND RELIABLE RETROSPECTIVE 1 OF URBANISATION sound knowledge of population for a thorough analysis of the agglom- obtain reliable data by combining A distribution is essential for food eration process in the region. identification, counting, delimiting policies. Prior to the Africapolis study, spatial boundaries and a historical the only data available was national The Africapolis study’s retrospective reconstitution of spatial growth of data based on different definitions data on West Africa’s urban population over 2 500 agglomerations (from maps, and few and sometimes contested from 1950 to 2000 corrects this situation satellite images and aerial photo- census data published by the United and constitutes a major contribution graphs) with census data and other Nations Population Fund (UNFPA). to knowledge of settlement patterns available population counts. Neither does this data allow for cross- in West Africa. The study explains country comparisons nor does it allow in detail the methodology used to Evolution du niveau d’urbanisation selon l’étude Africapolis (agglomérations de plus de 10 000 habitants) URBANISATION Urban population trends in West Africa RaTE (centres with population over 10 000 inhabitants) Based on the same definitions for urban population, the population data are compa- rable between countries and have been integrated into an international urban database (e-geopolis). Evolution du niveau d’urbanisation selon l’étudein A1950fricapolis : 7.5 % (agglomérations de plus de 10 000 habitants) 125 urban agglomerations 4 million urban dwellers in 2000 : 31 % 992 urban agglomerations 78 million urban dwellers Source : Africapolis 2009 © Sahel and West Africa Club Secretariat (SWAC/OECD), 2011 2 WesT AFRIcaN FUTURes / N°01, JUNE 2011 © Sahel and West Africa Club Secretariat (SWAC/OECD) LARGER TOWNS AND 2 MORE TOWNS or each country and for the is not substantially different from F region as a whole, the report the one established (up to 1990 and gives the same decadal dates (1950, with less precision) by the West 1960…2000); total urban population African Long-Term Perspective Study and a breakdown of urban centres into “Preparing for the Future: A Vision of population size brackets (10–20 000, West Africa in the Year 2020” (WALTPS) 20–50 000, 50–100 000, etc.). This produced by the Club du Sahel in breakdown allows for a “Rank-size 1998. In particular, the Africapolis distribution of agglomerations in West study confirms that the region’s urban Africa” graph. population increased 10 fold between 1950 and 1990 (and 20 fold between The linear shape of the rank-size distri- 1950 and 2010) and that the number bution and its parallel shifts over time of urban centres with populations (1950 to 2000) show that urbanisation above 10000 has grown continuously, and urban growth does not only affect from 125 in 1950 to over 1000 today. the largest cities but also small and The average distance between urban medium-sized urban centres, a fact centres of over 10 000 inhabitants has often overlooked. declined from 111 km to 33 km. This has driven and considerably improved The picture of West African urbani- the integration of rural areas in the sation that emerges from this study market economy. RaNK-SIZE DISTRIBUTION OF URBAN AGGLOMERATIONS This figure presents a ranking (in decreas- ing order of size) of all agglomerations 10 000 000 Lagos identified by Africapolis on a logarithmic scale. Each centre is identified by its place 5 000 000 4 000 000 bidjan a in the ranking order (horizontal axis) and A cr c ar A Ibadan its population Pn (vertical axis). From the Dak ano graph obtained, we can assess the extent 2 000 000 K umasi to which the distribution deviates from K Zipf’s law, which links a centre’s popula- 1 000 000 2000 tion to its rank by the relationship Pn = 1990 A/n, represented by the black dotted line. 500 000 400 000 1980 It shows the trend of this distribution from 1950 to 2000. 1970 200 000 Population 1960 In 2000, the largest city, Lagos, was several times larger than the next four 100 000 1950 cities: Abidjan, Accra, Ibadan and Dakar, but it has not achieved “primatial” status 50 000 40 000 (i.e. having a population five or more times larger than the next largest city. This is 20 000 a sign of the regional market’s gradual integration without total domination by its 10 000 largest city. 5 000 1 2 3 4 5 6 7 10 20 50 100 200 300 500 1.000 Rank by size © Sahel and West Africa Club Secretariat (SWAC/OECD), 2011 © Sahel and West Africa Club Secretariat (SWAC/OECD) WesT AFRIcaN FUTURes / N°01, JUNE 2011 3 CHOOSING A LARGE DIFFERENCES 3 NUMERICAL 4 IN URBANISATION RATES DEFINITION OF URBAN POPULATION Degree of urbanisation in West Africa: results of the Africapolis study 1950 1970 omparing urbanisation trends C over time and across countries requires the definition of some numerical threshold. Yet no definition of an urban area based on numbers (agglomeration of 5 000, 10 000 or MAURITANIA MAURITANIA 20 000 people) is fully satisfactory. An agglomeration of 5 000 inhabitants in a sparsely populated area can be SENEGAL NIGER SENEGAL NIGER MALI MALI characterised as a “town” whereas THE GAMBIA THE GAMBIA another of 10 000 inhabitants in GUINEA BISSAU BURKINA FASO GUINEA BISSAU BURKINA FASO a very dense rural area may be GUINEA GUINEA BENIN BENIN characterised as a “large village”. The NIGERIA NIGERIA SIERRA LEONE authors of Africa polis have opted for SIERRA LEONE TOGO TOGO a threshold of 10 000 inhabitants to CAPE VERDE COTE D’IVOIRE CAPE VERDE COTE D’IVOIRE define an urban area, regardless of its LIBERIA GHANA LIBERIA GHANA economic functions and administrative Degree of urbanistion boundaries. less than 25% 25 > 40% 2000 The linear shape of the rank-size distri- more than 40% butions also suggests that the threshold Degree of urbanistion in percent 50 of approximately 5 000 inhabitants 1950 (used by WALTPS) would increase the 1970 40 number of urban centres and hence 2000 urban population and urbanisation rate at each date by the same amount MAURITANIA 30 as the 10–20 000 bracket (see dotted 20 lines). The relative trend in this data over time would not be significantly SENEGAL NIGER MALI 10 affected; what matters is to keep to the THE GAMBIA same numerical threshold over time. GUINEA BISSAU BURKINA FASO n re a i GUINEA ogo rde BENIN T Ve Mal Niger NIGERIA Beni Ghana Liberia Nigeria Guinea Senegal Cape Mauritani Gambia (the) Côte d’Ivoi Sierra LeoneBurkina Faso SIERRA LEONE TOGO Guinea-Bissau CAPE VERDE COTE D’IVOIRE LIBERIA GHANA Source: Africapolis 2009 4 WesT AFRIcaN FUTURes / N°01, JUNE 2011 © Sahel and West Africa Club Secretariat (SWAC/OECD) LARGE DIFFERENCES 4 IN URBANISATION RATES he study calculates an urbanisation Degree of urbanisation in West Africa: results of the Africapolis study T rate for each country and for the region as a whole. Comparing urbani- sations rates rather than nominal size 1950 1970 of urban population is more inform- ative in terms of settlement transfor- mations in a region where countries differ widely in population size (from Cape Verde’s 500 000 to Nigeria’s 100 million plus). MAURITANIA MAURITANIA The average weighted regional urbani- sation rate (32%) is greatly influenced SENEGAL NIGER SENEGAL NIGER by Nigeria as it accounts for half the MALI MALI THE GAMBIA THE GAMBIA region’s total population. GUINEA BISSAU BURKINA FASO GUINEA BISSAU BURKINA FASO Compared to the regional average in GUINEA GUINEA BENIN BENIN NIGERIA NIGERIA 2 000 (32%), urbanisation rates in the SIERRA LEONE SIERRA LEONE TOGO TOGO region range from 16% in Niger to 46% in Senegal. COTE D’IVOIRE CAPE VERDE COTE D’IVOIRE CAPE VERDE LIBERIA GHANA LIBERIA GHANA Degree of urbanistion Seven countries have urbanisation less than 25% rates close to or above 40%, all 25 > 40% being coastal countries; 2000 more than 40% Four countries have urbanisation Degree of urbanistion in percent rates below 25%, which include 50 1950 the landlocked Sahelian countries 1970 (Burkina Faso, Mali and Niger) 40 2000 already the least urbanised in 1950 and Sierra Leone, among the most MAURITANIA 30 highly urbanised in 1950 but has been through a long socio-political 20 crisis; NIGER SENEGAL Five countries have an urbanisation MALI 10 THE GAMBIA rate between 25 and 40% all being GUINEA BISSAU BURKINA FASO coastal countries.