This study describes how some biofuels are produced, emphasizing agricultural production systems, and considers what is needed in order to measure and communicate environmental performance, and gives examples of how this might be done. We describe a set of seven uses of a Green Biofuels Index, from a wholly market-driven implementation through a set of increasingly intrusive regulatory approaches. We then present several case studies of specific biofuel production pathways using a lifecycle analysis of the inputs to feedstock production and processing, but excluding market-mediated effects...