The environmental impact of fresh tomatoes consumed in cities: A comparative LCA of long-distance transportation and local production

Abstract

Eight scenarios of fresh tomato supply to urban citizens were analysed using a Life Cycle Analysis (LCA) approach. Two of the scenarios corresponded to unheated greenhouses and a long distance transportation to the final consumer; four scenarios corresponded to zero-miles agriculture in a rural environment, including heated greenhouses, unheated greenhouses and open-field production; another two scenarios corresponded to Urban Agriculture (UA). The objective was to compare the environmental impacts of the production and transportation of tomatoes to the final consumer. Zero-miles production in heated greenhouses had the highest environmental impact (e.g. the Global Warming Potential GWP was 0.33 kg CO2 eq per kg of tomato), to such an extent that production in unheated greenhouses far away was comparatively better (GWP was 0.21 kg CO2 eq). Conversely, zero-miles production in the open-field was, environmentally, the best option with a GWP of 0.12 kg CO2 eq. Interestingly, the distance travelled by the product was less important than the efficiency of the transport. Other important environmental burdens were inefficient irrigation, chemical disinfection of the soil and the technological appliances used for micro-agriculture. As a consequence, the best zero-miles agriculture scenario was not the one where tomatoes were grown closest to the consumer's table, but the one that used the most efficient and less contaminating agronomic management and transport strategy. Thus, UA was not environmentally superior to zero-miles agriculture carried out in rural areas; conversely, rural horticulture helps to stabilize the population in regions suffering from depopulation.