Climatic impacts of different vegetable oils: A measurement-based life cycle analysis

The production of vegetable oils takes up a considerable portion of global arable land and has steadily increased during the 21st century. In the European Union, the growing of oil crops covers approximately 17% of arable land but the region also relies heavily on imports, particularly of palm oil and sunflower seed oil. So far, there are only few measurement-based estimates of the greenhouse gas budgets of agricultural systems, including the growing of vegetable oil crops. In this study, we evaluate and compare the global warming potential of cultivating four commonly used vegetable oils. Two of the oils, palm oil and soybean oil, are largely imported to the EU while the other two, olive oil and rapeseed oil are largely produced within the region. We use a comprehensive measurement-based Life Cycle Analysis (LCA) framework, combining the traditional LCA (using OpenLCA software and data from Ecoinvent database) with detailed greenhouse gas flux measurements of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) from existing agricultural fields. We selected existing measurement sites in Indonesia for palm oil, Spain for olive oil, Argentina for soybean oil and Germany for rapeseed oil. Measurements of ecosystem CO₂ fluxes were done using eddy covariance while chamber methods were used for N₂O and CH₄ fluxes. This approach allows us to provide a detailed assessment of the emissions from the cultivation, including all the inputs and field emissions, to the production of these oils. These results contribute to understanding the climatic impacts of vegetable oil production, providing valuable insights for policy-making, agricultural management, and consumer choices aiming at mitigating the environmental footprint of agriculture, both from the production and consumer’s point of view.