Life cycle assessment of greenhouse gas emissions associated with biofuels should not only consider fossil fuel inputs, but also N(2)O emissions and changes in carbon stocks of (agro) ecosystems linked to the cultivation of biofuel crops. When this is done, current plant oils such as European rapeseed oil and oil from soybeans and oil palms cultivated on recently deforested soils have higher life cycle greenhouse gas emissions than conventional diesel. (C) 2010 Elsevier Ltd. All rights reserved.