URBAN FOODPRINTS (UF) - ESTABLISHING BASELINE SCENARIOS FOR THE SUSTAINABILITY ASSESSMENT OF HIGH-YIELD URBAN AGRICULTURE

摘要

Allowing for significant water savings and year-round yields, Controlled-Environment Agriculture (CEA) is oftentimes portrayed as a sustainable alternative to conventional farming, and its practice in urban areas as a food, income and employment generator is expanding worldwide. Particularly in today's fast growing cities, where economic strength is buying food security through imports, a large-scale implementation of such practices should be further investigated as potential contributors - not only to food security but also to self-sufficiency - for the production of horticultural crops. However, further than quantifying the potential for food self-sufficiency of cities through urban cultivation, there is a crucial need for assessing the extent to which such scenarios are effectively more sustainable than existing supply chains. For that purpose, this paper presents the Urban Foodprints (UF) methodology, a fundamental preliminary step in the sustainability assessment of high-yield urban agriculture, consisting of collecting and integrating data on the existing supply chain, to be used as a baseline scenario in the environmental performance analysis. Through the case of Riyadh, Saudi Arabia, where harsh climatic conditions, a heavy reliance on food imports and a growing population constitute major threats to food security, the UF method is described and applied to the top four consumed horticultural crops -watermelon, tomato, onion and carrot. The environmental sustainability of high-yield urban agriculture in Riyadh is subsequently assessed for tomato, as a comparison of the resulting city's current foodprint for the crop vs. a scenario of local production in CEA urban farms. Results show that urban production in high-yield greenhouses has the potential to reduce Global Warming Potential (GWP) by 9%. However, while water savings contribute greatly to reducing irrigation-related emissions and food miles are considerably reduced, the energy needs of the greenhouses a