What is it about?
The urban population is growing fast in Africa. Is this population increase concentrating in the existing cities and towns or joining new settlements scattered across the geographical space? Using a panel dataset of 3.8 million rectangle-shaped cells covering the entire territory of Ghana between 1975 and 2014, we find a large increase in small and medium urban settlements: urbanization happened not just in a few large cities. More importantly, urban growth in Ghana has not taken the form of a disproportionate expansion of partially built cells. Rather, towns and cities crowded out their hinterland, following a more compact growth than evenly spread urban growth.
Featured Image
Photo by The Artboard on Unsplash
Why is it important?
How the rapid expansion of human settlements unfolds over geographical space has deep consequences for inequality, poverty, climate mitigation, and urban planning. If partially built-up areas grow disproportionately over time because of the growth of urban areas, this creates different needs for public infrastructure investment and market development than if population growth concentrates in a few high-density areas. Our evidence suggests that Ghana can use two important predictors of future build-up areas to locate its provision of urban infrastructure and services: the presence of a road and the existence of already built-up areas.
Perspectives
Traveling through developing countries, we are often struck by the apparently haphazard placement of human settlements. My long-term co-author and I often wondered how these settlements are formed and how infrastructure and services should be planned to service them. We were pleasantly surprised with two findings from this study: (i) densely built areas do not necessarily sprout at regular intervals along roads or across the landscape; yet (ii) the growth of built-up areas is not randomly distributed, it concentrates around already built-up areas, indicating the presence of agglomeration externality. We hope that this type of analysis will become an important part of the design of urbanization and infrastructure policies in developing countries.
Forhad Shilpi
World Bank
Read the Original
This page is a summary of: The evolution of built-up areas in Ghana since 1975, PLoS ONE, May 2021, PLOS,
DOI: 10.1371/journal.pone.0250847.
You can read the full text:
Contributors
The following have contributed to this page
