The Role of Climate Change in Africa’s Urbanization

Globalization and structural changes in African economies are contributing to rapid urbanization—with 50 percent of the population predicted to live in urban areas by 2030, compared to 36 percent in 2010. Simultaneously, climate change is projected to have significant impacts on the African landscape with decreased precipitation, increased aridity, and declining agricultural productivity. With the majority of rural communities relying heavily on agriculture for food and employment, these predicted environmental changes are leading academics and policy makers to place a higher emphasis on the role of climate change in influencing rural-to-urban migration.

In a recent paper published in the Journal of Development Economics, Henderson et al. examine urbanization trends in Sub-Saharan Africa, acknowledging that climate change will lead to a loss of up to 15 percent in predicted agricultural yield by 2050, and up to 47 percent by 2090. The economic implications of these changes are explored in two ways: Does climate change incentivize rural-to-urban migration? If so, does this increase incomes in nearby cities by providing additional labor?

The authors explore these questions by first analyzing within-district urbanization using census data for 359 districts in 29 Sub-Saharan African countries coupled with temperature and rainfall data to measure climate variability and local urban migration patterns. Second, satellite data measuring growth in night lights—previously shown to be highly correlated with income—was added to measure the effects on city incomes resulting from urban migration.

In answering these questions, the level of industrialization in a district served as a key factor in predicting urbanization due to climate change. Compared to districts solely focused on agricultural production, districts that also had manufacturing industries producing tradable goods to be sent out of the district had much higher urban migration rates, under similar climate scenarios. In districts with a high manufacturing presence, urban migration provides an escape from declining rural agricultural productivity by providing alternative economic opportunities, consequently raising cities’ total income. These urban push factors increase with industry presence, meaning that migration was more likely in cities with a greater number of industries present.

In districts without manufacturing, rural-to-urban migration was little to none, as urban migration served no added economic benefit. These districts also experience zero or slightly negative income effects as agricultural productivity declines due to climate change.

Climate change, however, is only one of many factors affecting urbanization in Sub-Saharan Africa. For example, previous research has argued that climate change engenders violent conflict, which may indirectly result in urbanization as displaced persons seek refuge in cities. In order to measure if violent conflict was causing the observed migration patterns, the authors believed they would need to observe differing levels of conflict between the most and least industrialized districts. To rule out this concern, the researchers compared detailed conflict data to the rainfall and night lights data, and found no statistically significant support for violent conflict driving climate related urbanization.

With the expected declines in agricultural productivity in Sub-Saharan Africa, these results suggest an increased rate of urbanization in districts that are more industrialized. However, with only 23 percent of the 359 districts sampled having some degree of industrialization, the large majority of districts facing little or no economic benefits from urban migration due to climate change will require alternative solutions.

In addressing sustainable solutions to climate change, good policy should account for the level of economic diversification and its role in urbanization and internal migration. Adopting modern agricultural practices, expanding irrigation, and encouraging the use of fertilizers and composting may prove effective in supporting at-risk communities. While such adoptions may provide only partial relief to the effects of climate change, continued research on climate related migration will be vital in adapting to the world’s changing economic and environmental reality.

Article source: Henderson, J. Vernon, Adam Storeygard, and Uwe Deichmann. “Has Climate Change Driven Urbanization in Africa?” Journal of Development Economics 124. (2017): 60–82.

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