Life cycle assessment:: a tool to evaluate and improve the environmental impact of Mediterranean greenhouses

Protected cultivation is aimed at obtaining higher yields by modifying and improving natural climatic conditions. In spite of the fact that Mediterranean horticulture is mainly based on low technology cold greenhouses, protected cultivation has a negative environmental impact. Nowadays, efforts are being made to improve the sustainability level of this cultivation system. This paper presents the adaptation of a known methodology, Life Cycle Assessment, LCA, to determine the environmental burdens associated with protected cultivation. LCA is a tool for assessing the environmental aspects and potential impacts associated with a product or a system. It considers the entire life cycle of a product from resource extraction to waste disposal. According to ISO standardisation guidelines, an LCA study can be divided into four steps: goal and scope definition, inventory analysis, impact assessment, and interpretation. In the goal and scope definition, the aim and the subject of an LCA study are determined and a 'functional unit' is defined, for instance, yield per square meter. In the inventory analysis, all extractions of resources and emissions of substances attributable to the studied functional unit are listed. In the impact assessment, the magnitude of the potential impact of individual substances within each impact category is determined. Impact categories correspond to environmental problems, such as human toxicity or ozone depletion. The final step in an LCA study is the interpretation of the results from the previous three steps, to draw conclusions and to formulate recommendations. This powerful tool can be used to identify the part of the whole production process in which the most important environmental damages are found and consequently apply the best technologies to mitigate them. LCA can also be applied to compare two different procedures to cultivate a crop, and decide which one has the best environmental behaviour considering its whole life cycle.