Abstract
Understanding the underlying causes and consequences of Africa’s rapid urban population growth is crucial to improving long-term prosperity. There are various schools of thought on the matter. One perspective holds that, whatever the causes, dense concentrations of population have the potential to transform economic circumstances and reduce poverty, provided that an efficient urban form is created (Collier and Venables, 2015). Many influential international organisations endorse this view and are actively encouraging African governments to embrace urbanisation and reap the benefits of an ‘urban dividend’ (Lall et al., 2017; United Nations, 2016; United Nations Economic Commission for Africa, 2017).
A contrary standpoint is that urbanisation driven by rural destitution, civil wars and environmental problems is likely to aggravate hardship, spread disease and increase congestion because resources available to invest in expensive urban infrastructure are deficient (Buckley and Kallergis, 2014). Accordingly, many governments believe that curbing the growth of large cities and skewing public finds towards the countryside will reduce pressure on urban systems, limit social discontent and avoid disasters (United Cities and Local Governments of Africa and Cities Alliance, 2013; Turok, 2015).
A third possibility reflects the experience of many Asian countries, where rising agricultural productivity and urban industrialisation have fuelled a virtuous circle of rising household incomes and higher tax revenues. The result has been ever-increasing investment in urban infrastructure, competitive businesses and decent housing (Ellis and Roberts, 2016; UN-Habitat, 2014; World Bank, 2013).
Government action depends on recognising why urbanisation is so significant. It also requires going beyond the symptoms of current urban problems to focus on the root causes. Securing high level political commitment requires reliable information on the broad dimensions of urban change, as well as finer-grained data on the structure and performance of settlements. Detailed evidence on the scale and determinants of population shifts is also necessary for more responsive spatial planning and for identifying future development land that can be formally registered, valued and taxed to generate revenues to finance urban infrastructure (Turok, 2016).
Therefore, information about the urbanisation process and its outcomes is an essential input – perhaps the vital first step – to persuade Africa’s decision-makers to support the growth of cities. Yet the quality of data on urban growth across the continent is surprisingly poor. Even basic statistics on city demographics, economic growth rates and forms of physical expansion are uneven and unreliable. This evidence is needed to inform a range of development policies, including investment in mass transit systems, adequate housing and schools in the right locations, assembly of suitable land for industrial uses, protection of water courses and other ecosystems, and cooperation between municipalities with boundaries affected by urban growth. Without robust information, it is difficult to rectify exaggerated claims that Africa’s urbanisation must be curtailed because it is unprecedented, explosive and catastrophic.
The purpose of the papers by Fox et al. (2017) and Potts (2017) is to clear up some of the empirical and conceptual confusion surrounding urbanisation on the continent. They seek to provide hard-headed assessments of changing urban patterns and dynamics. Key questions include: is urbanisation accelerating or slowing; how is the process affected by shifting economic conditions; and are (ungovernable) megacities growing more quickly than secondary cities and towns? These are weighty issues with far-reaching consequences for the sustainability of Africa’s urban growth and for the quality of life.
An immediate difficulty revealed by both papers is that countries define and measure urban centres in different ways, using various criteria and size thresholds. In some places these categories have also been altered over time and in arbitrary ways, raising suspicions of interference to divert resource allocations towards favoured regions. This creates real problems for comprehending what is happening and embarking on policies to manage urban development more effectively. Inconsistent urban definitions yield different portraits of the national urban system, different accounts of rural–urban migration, and different interpretations of how territories are being reshaped. Incompatible definitions also complicate cross-country comparisons and confound efforts to develop more general understandings of urban growth dynamics.
Urbanisation itself is also defined differently, sometimes going beyond the common-sense net shift in the population from rural to urban areas, to include the overall growth in the urban population and even the physical expansion of urban centres (Fox et al., 2017). International and domestic analysts alike rely heavily on population census data, but censuses are infrequent in many places, so the basic information for future projections can be very old. Fortunately the situation is beginning to improve with the increasing availability of satellite imagery and more regular household surveys in many nations.
Incorporating the economic drivers of urbanisation
Potts (2017) is particularly concerned that countries define urban areas inappropriately, so that both the level of urbanisation and the rate of urban population growth are overstated. She provides striking examples of deficiencies in urban data, as well as glaring errors in how people and organisations have interpreted the data. Basic measurement flaws and inaccuracies mean that Africa’s changing urban landscape is regularly misrepresented and misunderstood. In some instances, urban areas only appear to be growing because boundaries or population thresholds have been altered, and analysts have somehow overlooked these simple explanations!
The most thought-provoking phenomenon discussed by Potts is the growth in size of many human settlements without their economies seeming to develop from agricultural activities (farming, forestry and fishing) towards other, higher productivity sectors. This is a puzzling occurrence involving rural consolidation and densification that clearly warrants further research. It carries risks as well as opportunities for these communities, because average incomes remain low, thereby constraining investment in public services and housing. Potts argues that these settlements should not be classified as urban because they remain dependent on rural activities. To avoid this distortion, the economic function of settlements should be factored into how they are defined.
She maintains that on logical grounds the transition from rural to urban societies necessitates a change in what settlements produce. Livelihoods should diversify from primary industries involving the husbandry of crops, animals and natural resources to other sectors that are less land-intensive. Settlements that grow larger and denser do not automatically become ‘urban’. Yet most African countries ignore this: agricultural occupations dominate the urban economies in four of the five countries Potts examines. This is most apparent for smaller settlements below about 15,000–20,000 population. Many seem to be hamlets, villages and small towns that have merged over time to create larger built-up areas. She maintains that they are merely enlarged rural settlements without the key characteristics of urban centres. Urbanisation is a more complex, thoroughgoing process associated with economic growth and reorganisation.
The flawed urban definition means that governments and international agencies frequently exaggerate the implications of settlement growth for societal wellbeing. By assuming that the concentration of population will almost inevitably raise productivity and stimulate economic growth (World Bank, 2009), some of them articulate an inflated narrative that places are becoming more prosperous than they really are. If economic criteria were embedded in their definition, there would be no pretence.
One has some sympathy for this broad proposition, given the importance of economic progress for urbanisation to be durable and liveable. Serious problems emerge when urban population growth is under-resourced. The low income, low investment character of urban growth fuels insecurity, overloads public services and degrades the environment. In addition, there is a compelling case for tackling the scarcity of economic data at the subnational scale, which is even worse than population data. However, Potts’ argument for ensuring that economic criteria are intrinsic to defining the urban is less convincing.
First, from a practical perspective, it would complicate efforts to document urbanisation. In many African countries the collection of primary data at this scale is already infrequent and uneven in quality. A more sophisticated urban definition would worsen the situation and reduce the amount of essential information on settlement patterns. Basic population data (a headcount) is simpler than economic data on jobs, occupations or incomes, and the key distinction in economic data between people’s place of work and residence does not arise to complicate matters further.
Second, from a comparative perspective, the need to include economic data would jeopardise historical analysis of trends because of the lack of consistent information for earlier periods. It would also make it more difficult to compare urbanisation in Africa with most other countries around the world, which do not incorporate economic criteria.
Third, from a conceptual perspective, there are difficulties in defining an appropriate economic threshold between urban and rural settlements, so it would be hard to operationalise. On what basis could one say that a settlement with, say, 40% agricultural employment was rural, whereas one with 30% agricultural employment was urban? Any meaningful threshold in a particular region and point in time is bound to vary greatly over time and between regions, depending on prevailing technology, natural resources, land availability and opportunities for other economic activities.
Agriculture may also be bound up with other occupations in ways that cannot easily be separated. Poor communities maintain multiple livelihoods to diversify their income sources and reduce the risk of destitution. The weakness of African urban economies is reflected in the co-existence of many informal activities, industries and occupations, including urban agriculture. Many households cultivate some crops or keep a few livestock on small plots in backyards or communal spaces to supplement meagre incomes and diets, but this does not define them as rural.
Summing up, efforts to bolster economic information for localities and regions, in parallel with more accurate demographic data, are crucial for improved understanding and policy action. However, it is probably sensible to keep these indicators separate and retain a simple, readily applied urban definition, rather than to conflate them and risk further confusion. Separate variables would also enable robust statistical analysis of the relationship between demographic trends and economic dynamics.
Downgrading the economic forces behind urbanisation
Nigeria has the biggest urban population in Africa and is projected to make the third largest contribution to the world’s urban population over the next few decades, after China and India (United Nations, Department of Economic and Social Affairs, Population Division (UNDESA), 2015). The size and location of its expanding cities have been heavily contested since independence, reflecting wider ethnic and religious tensions. Fox et al. (2017) analyse spatial demographic trends using a variety of data sources to consider whether the pace of urbanisation has slowed in recent years. They critique an earlier paper by Potts who claimed that urbanisation in Nigeria has stalled following an economic slowdown.
Fox et al. (2017) confirm the limitations of the country’s urban data, but stress the value of combining information from multiple sources, including satellites. The data drawbacks are serious when examining specific settlements, but less significant for discerning broad patterns and trends. Their main conclusion is that Nigeria’s urban population is continuing to grow quickly, despite the country’s economic difficulties. This is attributable mainly to the natural increase in the population, following a decline in mortality and continuing high fertility. Rural–urban migration is far less important, although it has also been spurred by pressures associated with demographic growth in the countryside. Rural conflict and climate change could contribute to substantial out-migration in the future.
Despite the sizeable increase in Nigeria’s urban population, the authors appear sanguine about its balanced distribution across the urban system. There does not seem to be a hazardous overconcentration in Lagos or other megacities. Instead, four new multi-polar urban regions are emerging. These are poorly grasped by traditional measures of city size, which treat cities as stand-alone phenomena. Against this, a potential concern is that the physical footprint of urban areas is outpacing population growth because of the lower density form of new development. Fox et al. do not discuss the consequences, but sprawling new and expanded settlements could have detrimental impacts on the costs of infrastructure, on energy consumption and on the condition of ecosystems.
Fox et al. are also critical of Potts’ assumption that urbanisation in intimately bound up with economic change. The fact that the natural increase in the urban population exceeds net migration, and that both continue despite a stagnant economy, is used to argue that urbanisation proceeds with considerable autonomy from economic conditions. There are separate demographic processes at work with different causal mechanisms related to human fertility and mortality. These need to be understood independently of changing economic circumstances.
This gets to the crux of the matter – how the relationship between urbanisation and economic development is conceptualised. Potts sees economic growth and reorganisation as the paramount driving force behind urbanisation. Urban population growth is deemed to have no influence back on the economy. It is purely a consequence rather than a cause of economic change, and there are no feedback effects, either positive or negative. This perspective is arguably partial and one-dimensional. It precludes the possibility of a two-way relationship between urbanisation and economic development in which the former either supports the latter through proximity and agglomeration economies, or hampers it through the drawbacks and diseconomies of urban density. There is no scope for urban population and economic growth to be interdependent and co-evolving processes (Turok, forthcoming). The narrow focus on the economy also denies the possibility of wider social and environmental influences on the pace of urbanisation, such as rural poverty and food insecurity.
In criticising Potts’ position, Fox et al. risk going to the opposite extreme and under-estimating the role of economic forces. Their preoccupation with the demographic drivers of urbanisation plays down the impact of shifting economic conditions. The state of the economy is seen merely as one of many factors influencing urban population growth. It appears to have no special significance, despite all the historic and contemporary evidence linking economic transformation and urbanisation around the world (Scott and Storper, 2015). Just as important, in examining the determinants of urbanisation Fox et al. say nothing at all about its various consequences. This is surprising bearing in mind how important it is to consider the repercussions and ramifications of Nigeria’s rapid urban population growth for its economy, society and environment. Will it help to raise living standards and improve resource efficiency, or exacerbate overcrowding and provoke social discontent?
Conclusion
There is considerable scope for improved information and research on the dynamics of urbanisation in Africa. There is insufficient investment in regular primary data collection and a lack of consistency in the definition and measurement of urban areas. Improved national statistics systems are necessary, perhaps supplemented by external arrangements to check and build confidence in the quality of these systems. Additional independent sources of data could play a helpful role in supplementing official statistics, taking advantage of the increasing availability of satellite imagery, administrative data, cell-phone records and other ‘big data’.
The case for better information and understanding of urban processes is compelling because of the momentous urban challenges and opportunities facing the continent. Improved evidence and knowledge about planning and managing urban growth could make a difference to the wellbeing of a sizeable section of global humanity. The recent burgeoning of interest in policies to shape Africa’s urbanisation by the UN, World Bank, African Union and other international organisations should be supported by an ambitious effort to strengthen the quantity and quality of urban statistics, data analysis and capacity building for urban research.
Reliable and regular data on three particular facets of urban change seem particularly important. First, demographic data are a fundamental requirement to monitor shifting patterns of human settlement, and to inform all kinds of development policies and resource allocation decisions. Second, enhanced economic data are also vital to document the changing economic functions of urban areas, and shifts in jobs, livelihoods and incomes across space and time. A third requirement is for better information on the changing physical footprint and spatial structure of urban areas, including population and building densities, the availability of public space and the existence of essential infrastructure. Robust information on these three inter-linked dimensions of urban transformation, organised on a common spatial platform for comparability, would go a long way to improve understanding of the urbanisation–development puzzle in Africa.
Footnotes
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.