As I mentioned in my previous article, urban farming appears to be a key component in redefining our relationship with food in cities. It can offer numerous opportunities to address issues such as food waste, the accessibility of fresh produce, and the overall efficiency of the urban food system. The positive consequences of this innovative and sustainable approach are abundant. However, it is not without its limitations. One of the central points of debate concerning urban farming revolves around how much food can actually be produced through this practice. A pilot study conducted at the University of Sussex in the UK sought to answer this question. Over a two-year period, two volunteer urban farmers in Brighton and Hove conducted experiments with urban farming in their gardens, balconies, and community spaces, known as "unlockments."

These spaces are designated for people in the neighbourhood to grow food, essentially creating urban vegetable gardens. The results of this study revealed that some participants were able to grow up to one kilogram of fruit per square meter in one season, while others managed to yield as much as 10 kg per square meter. These numbers would place urban farming within the production range of traditional medium-sized or small farms, suggesting that urban farming could potentially make a significant contribution to the food supply, particularly for fresh fruit, vegetables, and herbs.

Simultaneously, an earlier study published in Nature Food argued that in today's globalized food systems, 80 percent of food demand could be met within a distance of 500 kilometres. This implies that, in theory, achieving a high degree of food self-sufficiency could be possible within relatively narrow geographical limits, given that our food sources currently span the entire globe. However, this consideration does not necessarily advocate for total isolation; rather, it suggests that a shift toward more localized production could help address some of the challenges associated with long food supply chains, which are contributing to the destruction of ecosystems in many countries.

Recently, the conflict between Russia and Ukraine has highlighted one of the risks associated with long food supply chains. Indeed, one of the impacts of this conflict was the interruption of Ukrainian grain shipments that were being sent all over the world, with a particular impact on developing countries in Africa. This event underscored the dangers of the overdependence of some regions on production and distribution from others. Africa is a particularly complex region in this context, where climatic factors, such as drought, are intertwined with economic policies that promote the cultivation of some crops for export and the import of others, creating an imbalance driven by unofficial laws set by global powers. However, without delving further into this topic, which, due to its importance, deserves an article of its own, the climate issue remains a key element in this debate.

Indeed, the climate crisis plays a significant role in shaping the future of urban agriculture. On the one hand, these practices represent a mitigation solution, helping to reduce food waste and harmful emissions. On the other hand, not all cities are suitable for urban agriculture, especially considering rising temperatures and global warming. Water availability is a critical issue as well. Urban agriculture must strive to use water efficiently, employing methods such as "precision farming" to utilize precisely the required amount without waste. However, in light of the impending water supply crisis that will threaten many regions, this could become a crucial challenge. Therefore, urban agriculture may be more easily practiced in some parts of the world and less so in others, influenced by climatic conditions and the availability of water resources. An interesting perspective is to create microclimates favourable to urban agriculture within hostile climates.

For example, vertical farms can adjust environmental conditions to create the perfect environment for growing specific foods. This concept challenges the traditional idea of dependence on external climatic conditions and could offer new opportunities for food production in cities. Through this method, food grows in vertically stacked layers or on vertically inclined surfaces, often in controlled environments like warehouses or buildings with controlled climates, lighting, and nutrient conditions. By using techniques such as hydroponics, aquaponics, and aeroponics to cultivate plants, they receive their nutrients through water solutions or mist instead of soil. Its aim is to optimize space and resources, making it possible to grow more food in smaller areas. It reduces the need for traditional farming practices like extensive land use and chemical pesticides and has the potential to revolutionize the agriculture industry by increasing food production efficiency and reducing the environmental impact of food production.

Shifting our focus to policy and institutions, both are beginning to recognize the potential of urban agriculture and consider it a vital component of future food strategies. The European Union, through the Farm to Fork Strategy, has shown a strong interest in urban agriculture as part of Europe's food supply. Numerous investments and support for urban agriculture initiatives are in the pipeline for the coming years. At the local level, many municipalities are actively promoting urban farming as part of their food policies. For instance, in Italy, the municipality of Milan established the Milan Urban Food Policy Pact in 2015, during the EXPO. This global initiative involves mayors from around the world in a commitment to collaborate on creating sustainable, equitable, climate-friendly, safe, and diverse food systems for their citizens. The pact aims to address issues such as food deserts (which were discussed in the previous article), food waste, and food security.

In a world where climate change and food-related challenges demand innovative solutions, urban agriculture is emerging as a promising answer. However, to ensure its long-term success, it is essential to address the challenges posed by climate change, water management, and adaptation to changing environmental conditions. Above all, institutions and policies must become more actively engaged in recognizing this need and supporting urban agriculture as an integral part of our future food security.