Life cycle assessment, C footprint and carbon balance of virgin olive oils production from traditional and intensive olive groves in southern Spain

Abstract

Olive oil production shapes the socio-economic and environmental life of many areas of the Mediterranean basin, especially southern Spain, the highest olive oil-producing region worldwide. Olive grove cultivation is tending to intensify from traditional low-density to intensive and high-density cropping systems, which might result in higher environmental impacts. The aim of this study is to estimate the environmental impacts, carbon (C) footprint and carbon balance of producing virgin origin olive oil in Spain from four traditional rainfed, four irrigated, and three intensive olive farms, including the processing phase. Environmental impacts of producing 1 kg of unpacked virgin olive oil at the farm and industrial phases were quantified with the Life Cycle Assessment (LCA) tool and a "cradle-to-gate” approach using data from surveys at these farms and 12 olive oil mills. On average, the farming phase accounted for 76.3% of the EIs. Therefore, to reduce the impact of the virgin olive oils production, most of the efforts should be made especially in the farming phase. Despite the high variability between seasons and between independent replicates of the same farming system, intensive farming had significant higher impacts on most environmental impact categories than traditional rainfed farming, mainly due to the application of nitrogen fertilizer, plant protection products and herbicides. In terms of climate change, the environmental impact of the functional unit is in the ranges of 1.80–2.41, 1.59–2.78 and 2.28–3.26 kg of CO2 eq. for traditional rainfed, irrigated and intensive, respectively. C footprint was negative and averaged −5.5, −4.3 and −2.7 kg CO2 eq. Olive groves are efficient atmospheric CO2 sinks mainly by fixing CO2 into permanent and non-permanent trees structures. The lower intensification of the traditional rainfed groves contributed more in mitigating the increase of atmospheric CO2. Finally, the C footprint and C balance are negative, especially in traditional irrigated and intensive farming. The application of organic sources of fertilizer and the implementation of temporary spontaneous cover crops, both technically and economically feasible, are sound strategies to achieve a positive carbon balance and reduce the impacts of olive cultivation.