Urban agriculture is expected to be an important feature of 21st century sustainability and can have many benefits for communities and cities, including providing fresh produce in neighborhoods with few other options.
Among those benefits, growing food in backyards, community gardens or urban farms can shrink the distance fruits and vegetables have to travel between producers and consumers – what’s known as the “food mile” problem. With transportation’s greenhouse gas emissions eliminated, it’s a small leap to assume that urban agriculture is a simple climate solution.
But is urban agriculture really as climate-friendly as many people think?
Our team of researchers partnered with individual gardeners, community garden volunteers and urban farm managers at 73 sites across five countries in North America and Europe to test this assumption.
We found that urban agriculture, while it has many community benefits, isn’t always better for the climate than conventional agriculture over the life cycle, even with transportation factored in. In fact, on average, the urban agriculture sites we studied were six times more carbon intensive per serving of fruit or vegetables than conventional farming.
However, we also found several practices that stood out for how effectively they can make fruits and vegetables grown in cities more climate-friendly.
Community gardens like Baltimore’s Plantation Park Heights Urban Farm provide a wide range of benefits to the community, including providing fresh produce in areas with few places to buy fresh fruits and vegetables and having a positive impact on young people’s lives. Preston Keres/USDA/FPAC
What makes urban ag more carbon-intensive?
Most research on urban agriculture has focused on a single type of urban farming, often high-tech projects, such as aquaponic tanks, rooftop greenhouses or vertical farms. Electricity consumption often means the food grown in these high-tech environments has a big carbon footprint.
We looked instead at the life cycle emissions of more common low-tech urban agriculture – the kind found in urban backyards, vacant lots and urban farms.
Our study, published Jan. 22, 2024, modeled carbon emissions from farming activities like watering and fertilizing crops and from building and maintaining the farms. Surprisingly, from a life cycle emissions perspective, the most common source at these sites turned out to be infrastructure. From raised beds to sheds and concrete pathways, this gardening infrastructure means more carbon emissions per serving of produce than the average wide-open fields on conventional farms.
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