Making Urban Agriculture More Carbon-Efficient

A recent study in Nature Cities found that urban agriculture has a carbon footprint significantly higher than that of traditional agriculture. On average, urban agriculture’s carbon footprint was six times larger per serving of food than conventional methods—0.42 kg CO2e versus 0.07 kg CO2e.

But according to the study’s authors, including CUNY SPH Associate Professor Nevin Cohen and CUNY Urban Food Policy Institute Director of Policy Rositsa Ilieva, there are steps urban farmers can take to make their projects less carbon intensive.

The study measured the lifecycle of urban agriculture infrastructure and activities in 73 sites in five countries, from individual gardens to large-scale urban farms. The greenhouse gas emissions from the urban sites were compared to conventional farming methods.

The results suggest that most of the carbon impact of urban farms comes from physical infrastructure like raised beds and fencing and other material inputs. To make urban agriculture more carbon-efficient, the sites and their infrastructure need to have longer lifespans. The material used to build farms and keep them running should be recycled and reused.

This is the first large-scale study that accounts for how most crops are grown in urban settings, with previous research focusing mostly on high-tech, energy-intensive methods like rooftop greenhouses and vertical farms as opposed to more traditional farming techniques like growing crops on open-air plots.

“Our findings are not a critique of urban agriculture, but instead indicate opportunities to make urban farms and gardens more efficient,” Dr. Cohen noted. “Urban farms and gardens are critical assets because they provide tremendous co-benefits, from improved health and wellbeing to spaces for people to socialize. They grow fresh healthy produce, cool our streets, and are spaces for kids to learn and have fun. But to have a smaller carbon footprint, cities need to ensure long-term tenure, and support a circular urban farm economy through programs like municipal composting and rainwater capture for irrigation.”

“As mayors, urban policymakers, and city planners seek to institutionalize urban farming into mainstream urban policy and develop comprehensive urban agriculture plans, it is key that we gain a deeper and holistic understanding of urban farming and its interconnected social and environmental dimensions,” says Dr. Ilieva.