Assessing the edible city: environmental consequences of urban agriculture in the US Northeast

Urban agriculture has been proposed as a means to reduce the environmental burdens of supplying cities with food. In relation to this the vision of ‘the edible city’ has emerged, whereby urban farming becomes an important... [ view full abstract ]

Urban agriculture has been proposed as a means to reduce the environmental burdens of supplying cities with food. In relation to this the vision of ‘the edible city’ has emerged, whereby urban farming becomes an important component of the city in form and function. Reviews have revealed significant knowledge gaps surrounding the environmental performance of urban food production. Earlier assessments have focused on single farms, and when scaled to the city level, assessments have used conventional farming as proxy data for urban farms. Here we studied the impacts of urban farming in the Northeast United States (US) using primary data from multiple farms and at the city scale. The Northeast US is chosen as a case since it has seen a fair amount of recent activity in promoting urban farming as a sustainable food supply both by municipal governments and entrepreneurs.

We combined nutritional surveys with the multi-region-input-output tool EXIOBASE 2.2 to develop baseline greenhouse gas and land occupation impacts for the City of Boston at sub-urban granularity. We then used mapping data estimate the space for urban food production between and on buildings in the city. Optimization algorithms were run to use urban farming to maximize reductions in food related carbon and land use impacts. From these simulations we predict that a fully realized urban farming system in Boston reduced food-borne carbon related impacts by less than 5% of the city’s total. Land occupation remained essentially unchanged, with a slight increase of 1%. In terms of interactions with city’s local material and energy metabolism, impacts on the hydrological, solid waste and building energy systems were minimal. The city’s urban farms were estimated to assimilate under 10% of Boston’s household organic waste. Building energy use and surface runoff were both reduced by less than 2%.

Despite the meager environmental gains of the edible city vision in Boston, urban agriculture appeared to be able to make important contributions to the city’s nutritional needs. Gaps in vegetable needs could be met with local agriculture. Moreover, we estimate a market value of over $150,000,000 for the food grown in the city, potentially providing jobs and income in some of Boston’s most impoverished areas.