Assessing the Environmental Impacts of Palm Oil
Kapitel i bok, 2011
Palm oil is used for cooking in Southeast Asia and Africa and as a food additive in a number of processed foods world-wide. The production of palm oil is increasing, and it is of special interest from a nutritional point of view due to its high energy content and its significant content of micronutrients. In addition, palm oil is increasingly used to produce various biofuels. Due to large production volumes and diverse applications of palm oil, it is highly interesting and important to study the environmental impacts of its production. This chapter discusses how the environmental impacts of palm oil can be assessed, focusing on the life cycle environmental impacts of palm oil in comparison to similar products. A brief overview of life cycle assessment as a method is given, and results are presented together with suggestions for environmental improvements of palm oil cultivation and production. It is shown that the magnitude of the environmental impacts connected to palm oil in relation to other products is heavily affected by the choice of environmental indicators, which in LCA studies consist of both an environmental impact category and a so-called functional unit. Regarding impact categories, the global warming and acidification potentials of palm oil are lower than those of rapeseed oil per kg oil. The water footprint of palm oil and rapeseed oil are about the same on a mass basis, but for the two land use indicators soil erosion and heavy metal accumulation, rapeseed oil has a lower impact than palm oil. Specific interest is given to the life cycle energy use of palm oil in response to the unclear and diverse definitions of this impact category in different studies. It is concluded that there is a need to carefully define the energy use impact category when reporting on palm oil or similar products, and also to differentiate between different kinds of energy sources. If instead of mass the micronutrient content is applied as functional unit, palm oil still has lower global warming potential and acidification than rapeseed oil when compared on the basis of vitamin E content. However, if β-carotene content is used as functional unit, rapeseed oil is not relevant for comparison due to its negligible content of β-carotene. For that case, palm oil is therefore instead compared to tomatoes on a β-carotene basis, since tomatoes are rich in β-carotene. The tomatoes were shown to perform better then palm oil regarding global warming potential on a β-carotene basis. The effects of time and scale on the environmental impacts of palm oil, which includes changes in technical performance and electricity sources, are also discussed in this chapter. It is shown that combustion of the methane formed from the palm oil mill effluent can significantly reduce the global warming potential.