Environmental life cycle assessment of organic food: a review

Summary

In recent years, there has been a growing interest in investigating whether the organic food production and consumption result in better environmental profile compared to conventional food. To assess and compare environmental impact of organic food with conventional food as well as to assess impact of life cycle assessment (LCA) methodological choices, this meta-analysis systematically analysed 104 published studies on both animal and plant products. This was done comparing eight impact categories of global warming (GWP), acidification, eutrophication, eco-toxicity potential, biodiversity loss, energy, water and land use for both mass- and area-based functional units from cradle-to-farm gate. The review shows that the majority of studies have been performed in Europe and North America, with a large focus on GWP and little focus on biodiversity loss, eco-toxicity potential and water use. Only few studies included the effect on soil carbon sequestration for estimation of GWP or direct land use change, and such studies were more recent. The meta-analysis showed variation within the results across different studies due to differences in compared systems and research methods. The only impacts that were found to differ significantly between the two production modes were lower GWP per area unit plus higher land use and lower energy use per mass unit for organic compared to conventional food. The key methodological challenges in LCA of food products are to develop methodologies to assess biodiversity, toxicity and land degradation and to improve models for better estimation of changes in soil carbon especially for organic food. Furthermore, the choice of the functional unit can affect the results. Therefore, including several functional units for LCA of organic food and assessing their impacts in a dietary context are required. Including results both at the product and diet level might therefore provide more holistic assessments and allow more comprehensive decisions.