Urban farming isn’t as climate-friendly as it seems, but these best practices can transform gardens and urban farms

Urban agriculture is expected to be an critical part of sustainable development in the 21st century and can bring many benefits to communities and cities, including providing fresh products in neighborhoods where there aren’t many other options.

Among these benefits, growing food in backyards, community gardens or on urban farms can shorten the distance that fruits and vegetables have to travel between producers and consumers, known as the “food chain.” the problem of the “food mile”Once you eliminate greenhouse gas emissions from transportation, it’s a tiny leap to assume that urban agriculture is a basic solution to the climate problem.

But is urban farming really as climate-friendly as many people think?

Our team researchers collaborated with individual gardeners, community garden volunteers, and urban farm managers at 73 sites in five countries in North America and Europe to test this assumption.

We found that urban agriculture, while having many benefits for communities, is not always better for the climate than conventional agriculture over the full life cycle, even when transportation is taken into account. In fact, on average, the urban agriculture areas we studied were six times more emission-prone per serving of fruit or vegetables than conventional farming.

However, we also found several practices that stood out as being effective in making urban-grown fruits and vegetables more climate-friendly.

What makes urban farming more carbon-intensive?

Most of the research on urban agriculture has focused on one type urban farming, often high-tech projects like aquaponics tanks, rooftop greenhouses, or vertical farms. Electricity exploit often means that food grown in these high-tech environments has a gigantic carbon footprint.

Instead we looked at life cycle emissions more common, low-tech urban agriculture – the kind found in urban backyards, vacant lots, and urban farms.

Our study, published on January 22, 2024modeled carbon emissions from agricultural activities, such as watering and fertilizing crops and building and maintaining farms. Surprisingly, from a life-cycle emissions perspective, infrastructure was the most common source in these locations. From raised beds to sheds and concrete paths, this horticultural infrastructure represents more carbon emissions per serving of produce than the average open fields on conventional farms.

But of 73 sites in cities including Fresh York, London and Paris, 17 had lower emissions than conventional farms. By examining what made these sites stand out, we identified several best practices for reducing the carbon footprint of urban food production.

1) Exploit recycled materials, including food waste and water

Using elderly building materials to build agricultural infrastructure, such as raised beds, can reduce the climate impact of recent wood, cement, and glass, among other materials. We found that recycling of building materials could reduce greenhouse gas emissions in a given location by 50% or more.

On average, our facilities used compost to replace 95% of synthetic nutrients. Exploit food waste as compost methane emissions from food waste buried in landfills and the need to synthetic fertilizers made from fossil fuels. We found that carefully managing compost can reduce greenhouse gas emissions by almost 40%.

Catch rainwater or grey water use from shower or sink drains can reduce the need for water pumping, water treatment, and water distribution. However, we found that few places used these techniques for the majority of their water.

2) Grow crops that, when grown conventionally, produce a lot of carbon dioxide

Tomatoes are a great example of a crop that can reduce emissions when grown in low-tech urban agriculture. Commercially, they are often grown in gigantic greenhouses that can be particularly energy-intensive.Asparagus and other products that need to be transported by plane Because they spoil quickly, they are another example of products with a gigantic carbon footprint.

By growing these crops instead of buying them in stores, low-tech urban farmers can reduce their negative impact on the environment (known as carbon emissions).

3) Keep your city gardens in good shape for a long time

Cities are constantly changing, and community gardens can be susceptible to development pressureHowever, if urban agriculture areas can remain in place for many years, the need for recent infrastructure can be avoided and other benefits to communities can still be provided.

Urban agriculture areas provide ecosystem services and social benefits such as: fresh productsCommunity building and education. Urban farms also create homes for bees and urban wildlifewhile offering certain protection against the urban heat island effect.

The practice of growing food in cities is further expansion is expected in the coming years, with many cities seeing it as a key tool for climate adaptation and environmental justice.

We believe that through careful site design and improved land-use policies, urban farmers and gardeners can raise benefits for both local residents and the planet.