Urbanization in Africa is accelerating rapidly and shows no signs of slowing down. An international team of researchers is targeting critical gaps in our understanding of how this urbanization affects local food and ecological systems, highlighting the importance of recognizing shifts in dietary patterns.
Since the early 2000s, Africa's urban population has more than doubled, reaching over 600 million in 2020. If current growth continues, the urban population is expected to double again by 2050. In Africa, the annual rate of urban area expansion exceeds the rate of urban population growth. Globally, future urban expansion is expected to cause significant losses in food production, reduce biodiversity and increase emissions from land-use change, endangering human livelihoods and the natural environment.
Recent research on the environmental impacts of urban expansion typically views this as the conversion of various land covers into urban land, focusing only on the direct impacts. From a new study published in Nature SustainabilityIIASA researchers and their colleagues demonstrate the complexity of expected urbanization and its many environmental consequences.
“Because Africa is urbanizing the fastest, the food system is also transforming rapidly. This puts great pressure on food security in what is already the most food insecure region in the world,” says Koen De Vos, author of the study and guest research assistant at the Integrated Biospheres Futures Research Group of the IIASA Biodiversity and Natural Resources Program. “In our study, we consider both direct land use changes and indirect effects, such as agricultural displacement and dietary changes associated with urbanization, especially with regard to rice consumption.”
The researchers developed a method to integrate all this information using the GLOBIOM model, creating a comprehensive, complex and multi-dimensional study that is unprecedented in its scope. The results show that, contrary to popular belief, the expansion of urban areas has a limited impact on the loss of food production, because agricultural land is simply expanded elsewhere. At the same time, the impact on natural lands is greater, as it includes not only the direct effects of the expansion of urban areas, but also the subsequent movement of agricultural land.
The most important environmental spillovers arise from changes in diet, especially rice consumption. As people eat more rice in African cities, more rice must be produced, resulting in greater dependence on imports and local production. Consequently, this leads to an increase in methane emissions, additional loss of natural lands, changes in water use and loss of biodiversity.
“This result adds to the growing evidence that our diet will be one of the most important factors for the health of the planet,” explains Marta Kozicka, co-author of the study and IIASA researcher at the Integrated Biospheres Futures Research Group.
In their study, the research team emphasizes that policymakers should adopt holistic approaches in the decision-making process. Integrating indirect impacts of land use and dietary changes into land use planning and policy making is essential to address future sustainability challenges.
