Consequential life cycle assessment: A tool to evaluate greenhouse gas emissions from soybean-derived biodiesel in Brazil

Global warming and oil dependency have driven meaningful development in the field of biofuel. Biofuels are expected to create new energy sources and reduce the net greenhouse gases emissions. However, one of the problems raised against the biofuel production growth is its impacts due to the expansion of agricultural area. In Brazil, due to the legislation, a percentage of biodiesel is already mixed with fossil diesel and this amount will increase during the next years. In Brazil, among many resources to produce biodiesel, soybean has an important role, representing around 90% of all sources. In order to supply the increasing demand of biodiesel it is expected that soybeans will occupy more land, including the Amazon Forest. This land transformation is also responsible for the emission of greenhouse gases due to the soil carbon emissions. In this context, this work focuses on how Life Cycle Assessment (LCA) could help in impact assessment on climate change caused by increasing soybean production areas in Brazil. Life Cycle Assessment (LCA), which is standardized according to ISO 14040, is a powerful technique to evaluate environment impacts of products and services, which takes into account all phases from extraction to final disposal. LCA has been used generally to evaluate the current situation, namely attributional LCA. However, soybean expansion is a scenario for the future, as well as its possible impacts. In this case, a Consequential LCA (CLCA) must be performed. CLCA aims at describing the effects of changes. To evaluate the consequences of the soybean increase production in Brazil, it was performed a literature review about the forecasts for biodiesel and soybean expansion in Brazil as well as about specialits opinions related to Amazon forest conversion to agriculture. The results showed that soybean production can not be expanded in the rain forest if it aims to replace fossil fuels for climate change reasons.