Abstract The food supply chains have significant impacts on the environment, consuming 30% of primary energy and 70% of freshwater withdrawals, and generating more than 20% of greenhouse gas emissions globally. The growing population and climate change will further escalate the stress on these resources, as the demand is expected to increase by 30%-50% in the next 20-30 years. Most importantly, the food, energy and water systems are inextricably linked and must be addressed on a nexus basis to avoid shifting of impacts from one system to another and to ensure the sustainability of their supply. This research has evaluated for the first time life cycle environmental impacts on the food-energy-water (FEW) nexus in the UK food sector, focusing on the following four subsectors, which together represent 70% of the food consumed in the UK: dairy, meat, fruits and vegetables. Life cycle assessment (LCA) has been used to quantify the impacts on the nexus of 127 products in these subsectors, considering fresh, frozen, canned, dried, fried and concentrated products produced domestically and imported from abroad. The LCA results have been used to estimate the impacts on the FEW nexus following a new methodology developed further as part of this work. The analysis has been carried out at both the product and sectoral levels. At the product level, meat and most dairy products have the highest impacts on the nexus per kg of produce, while fruits, vegetables, milk and yogurt have the lowest. However, if fruits and vegetables are air-freighted, grown in heated greenhouses, frozen and/or packed in glass/can packaging, their impacts increase significantly. For example, asparagus and mangoes have the highest nexus impact among the vegetables and fruits as a high proportion is air-freighted. Melons and cabbage have the lowest impact as they are consumed fresh and travel short distances. In the meat sector, lamb has the highest and poultry the lowest impact on the nexus. Generally, the key hotspots for the nexus are farming, including heated greenhouse cultivation, air-freighting, processing, refrigerated storage, oven cooking at home and packaging, but their contribution varies widely among the products. Taking the annual consumption into account at the sectoral level, the four sectors use 800.4 PJ of primary energy and 814.8 Mm3 eq. of water, occupying 8 Mha of agricultural land and generating 91.3 Mt of CO2 eq./yr. The meat supply chain accounts for the highest overall impact on the nexus (62%), despite occupying only 17% of the total food sector in terms of consumption. The vegetables and dairy sectors account for 21% and 13%, respectively. The contribution of the fruits sector to the total nexus impact is small (4%), despite having the highest water footprint among the sectors. The meat sector stresses the food and energy aspects the most while the dairy sector has the highest impact on the water aspect. The food aspect is affected the least by the fruits and vegetables, but they affect the water and energy aspects, respectively. In the vegetables sector, potatoes cause the highest FEW nexus impact due to their large consumption, while in the fruits sector, oranges are responsible for the highest impact due to their processing into juice, which represents 80% of the consumption in this sector. In the dairy and meat sectors, milk and beef are the most significant contributors to the overall nexus impact. These results indicate the necessity for reducing meat and moderating dairy consumption to reduce the impacts on the nexus. Imports of fruits and vegetables from water-stressed regions and air-freighting should also be avoided, eating instead seasonally and locally grown produce. Open-display cabinets at the retailer should be replaced by glass-door cabinets and oven-cooking at home should be minimised. The results of this work will be of interest to food producers, manufacturers, retailers and consumers to help them make more informed decisions towards reducing the environmental impacts in the FEW nexus.
|Date of Award||1 Aug 2019|
- The University of Manchester
|Supervisor||Adisa Azapagic (Supervisor) & Harish Jeswani (Supervisor)|