Rethinking Urban Spaces to Improve Nutrition Security Through Urban Agriculture

The current food system damages the environment, increases social inequalities, and is vulnerable to climate shocks and supply chain disruptions. This, and the global urbanization trends, pose the question of how cities will ensure food security for their inhabitants in a sustainable way. Within urban contexts, the most marginalized groups are also the most affected by premature deaths and non-communicable diseases, whose first preventable cause is nutrition. Here we analyze the potential of soil-based urban agriculture (UA) in providing fresh and nutritious food to urban populations. Using the megacity of São Paulo, Brazil, as a case study, we identify spaces for UA considering natural and context-related factors and select crops according to the gap between the current diet of the population and a reference balanced diet. To maximize water use efficiency, we test crops with an agro-hydrological model. Finally, we optimize crop-area allocation to find configurations capable of closing the diet gap for most people while minimizing irrigation water demand. The results show that the average hectare of urban garden in São Paulo could provide healthy food to more than 600 people, while theoretical city-scale implementations reach 13%–21% of the city's population. This demonstrates UA's high potential for significant fresh and nutritious food production but also the trade-offs that emerge when upscaling its implementation. While preliminary with respect to socio-economic considerations necessary for the implementation of such a strategy at the city scale, this coupled biophysical and nutritional framework can be repeated in other urban contexts.