In the heart of our modern cities, urban agriculture is silently (and slowly) taking hold. Many (including me) see it among the keys to a more sustainable future, and welcome its expansion. However, a recent study from the University of Michigan challenges our perceptions by revealing that, in terms of carbon footprint, urban agriculture may be much less sustainable than its conventional counterpart.
Published in Nature Cities (find the references at the end of this article), the study sheds light on a surprising truth, and also opens an essential dialogue on how we can optimize urban agriculture for a truly positive environmental impact. To live better, using ideas from other articles, in the arcology.
Carbon footprint of urban agriculture
As mentioned, urban agriculture has long been praised as an innovative solution for the sustainability of cities. In particular, its promise to reduce the distance between producers and consumers and improve urban food resilience gives hope. However, research from the University of Michigan offers a new perspective, demonstrating that the carbon footprint of urban agriculture can be significantly higher than traditional farming methodologies. According to the study, on an average basis, food production through urban agriculture emits 0,42 kg of CO2e per portion, six times more than the 0,07 kg CO2e per portion of conventional production.
Detailed analysis
The study analyzed three types of urban farming sites: urban farms, individual gardens and community gardens. This detailed analysis, which included 73 sites in five countries, took into account greenhouse gas emissions associated with agricultural materials and activities, such as infrastructure, supplies and irrigation. The results showed that most of the climate impact on urban farms it is driven by the materials used to build them.
Interestingly, the study identified significant exceptions. For example, tomatoes grown in open urban areas have shown lower carbon intensity than those grown in conventional greenhouses. Furthermore, the difference in emissions between urban and conventional agriculture disappears for products transported by air, such as asparagus. The authors of the study suggest that focusing on crops typically grown in greenhouses or transported by air could reduce environmental impact. Other strategies include extending the life of infrastructure, using municipal waste as an input, and generating high levels of social benefits.
Urban agriculture: social and nutritional impact
Despite the higher carbon footprint, however, urban agriculture continues to offer important social and nutritional benefits. Urban farmers and gardeners report improvements in mental health, diet and social networks. These benefits, together with potential solutions to reduce environmental impact, highlight the importance of considering urban agriculture holistically as part of urban sustainability strategies. However, we must work to ensure that it is truly less polluting, and not just a facade.
It is crucial to explore ways to make urban agriculture more sustainable. The University of Michigan research is a significant step in this direction, providing concrete data and practical suggestions. With an informed and proactive approach, urban agriculture can not only nourish bodies but also support a more sustainable future for our planet.
References and insights
For further information, you can consult the full study published in Nature Cities: “Comparing the carbon footprints of urban and conventional agriculture” (DOI: 10.1038/s44284-023-00023-3), available on the website www.nature.com/articles/s44284-023-00023-3.
