Fruits and vegetables grown in urban gardens in Europe and the US have a carbon footprint six times larger on average than the same produce grown on conventional farms, according to researchers.

Farmers and gardeners at 73 urban agriculture sites in France, Germany, Poland, the UK, and the US participated as citizen scientists in the research led by scientists at the University of Michigan and published on Monday in Nature Cities. The study is the largest ever conducted comparing the emissions of urban and conventional agriculture.

Researchers tracked greenhouse gas emissions from farm infrastructure, supplies, and irrigation water through daily diary entries made during the 2019 season. They found that, on average, food grown in city gardens emitted 0.42 kilograms (0.9 pounds) of carbon dioxide equivalent per serving, compared to 0.07 kilograms of CO2 equivalent per serving for food from conventional farms.

However, some crops proved to be less carbon-intensive when grown in cities than on conventional farms. Urban tomatoes often outperform conventional tomatoes, mainly due to the energy intensity of commercial greenhouses. Highly perishable conventional vegetables like asparagus, which are often distributed by plane, also have an equal or higher carbon footprint than the same crops grown in cities.

Read the entire article at Bloomberg