Reducing greenhouse gas emissions with urban agriculture: A Life Cycle Assessment perspective

The production and supply of food currently accounts for 20–30% of greenhouse gas (GHG) emissions in the UK and the government and nongovernmental organisations are seeking to reduce these environmental burdens. Local authorities all over UK establish community farms with the aim to produce more sustainable food for citizens. This study used environmental Life Cycle Assessment (LCA) to quantify the potential savings of food-related GHG emissions that may be achieved with the establishment of an urban community farm, based on a case study recently found in the London Borough of Sutton. The work identified elements of the farm design that require the greatest attention to maximise these savings. The greatest reductions can be achieved by selecting the right crops: (i) providing the highest yields in local conditions and (ii) usually produced in energy-intensive greenhouses or air-freighted to UK from outside Europe. Implications from further development of the farm on the local, unused land were examined, taking into account market requirements. This showed that land used on an urban fringe for food production could potentially reduce greenhouse gas emissions in Sutton by up to 34 t CO2e ha−1 a−1. Although the percentage of this reduction in total diet emissions is relatively low, the result exceeds carbon sequestration rates for the conventional urban green space projects, such as parks and forests.

► Community farms can help to reduce greenhouse gas burdens from food.
► Reductions highly depend on the design of the cropping pattern.
► LCA can be used strategically to examine various available options.
► Conventional supply attributes and local market requirements must be considered.