A comprehensive international study led by the University of Michigan unveils a surprising finding: fruits and vegetables cultivated in urban farms and gardens carry an average carbon footprint six times greater than conventionally grown produce. While urban farming offers social and nutritional benefits, the study emphasizes the need for sustainable practices to align with environmental goals.
URBAN FARMING; CARBON FOOTPRINT DISPARITY IN URBAN AGRICULTURE
The study compares the carbon footprints of low-tech urban agriculture to conventional crops, using data from 73 urban farms and gardens across five countries. Urban farms, individual gardens, and collective gardens were analyzed, revealing an average carbon intensity of 0.42 kilograms of CO2 equivalents per serving, six times higher than the 0.07 kg CO2e per serving of conventionally grown produce.
EXCEPTIONAL CASES: TOMATOES, ASPARAGUS, AND CLIMATE IMPACT
Certain urban-grown crops showcased exceptions to the trend. Tomatoes grown in open-air urban plots exhibited lower carbon intensity than those in conventional greenhouses, while air-freighted crops like asparagus eliminated the emissions difference between conventional and urban agriculture. The study suggests cultivating such crops and making site design adjustments for reduced climate impact.
BEST PRACTICES FOR URBAN AGRICULTURE SUSTAINABILITY
Extend Infrastructure Lifetimes: Prolong the lifespan of urban agriculture materials and structures, such as raised beds and composting infrastructure. Infrastructure longevity significantly impacts the carbon footprint, with a raised bed used for 20 years having a lower environmental impact per serving than one used for only five years.
Urban Symbiosis: Engage in “urban symbiosis” by repurposing urban waste, such as construction debris and demolition waste, for urban agriculture inputs. This practice contributes to conserving carbon and includes initiatives like composting and utilizing rainwater and recycled grey water for irrigation.
Maximize Social Benefits: While not directly reducing carbon footprint, maximizing social benefits such as improved mental health, diet, and social networks can enhance the competitiveness of urban agriculture. The study highlights the holistic consideration of nonfood outputs in assessing urban agriculture’s overall impact.
As cities increasingly embrace urban agriculture, this study provides valuable insights for practitioners to balance the environmental impact with the positive social contributions of urban farming.
