Reviewing models of land availability and dynamics for biofuel crops in the United States and the European Union.

The biofuel-related land use in the USA and the EU has significantly expanded during the last decade; models have been used to estimate land availability and demand in these regions. This paper provides an overview of different land-use modeling practices applicable to first- and second-generation biofuels. We review the importance of different land categories for biofuels, modeling approaches (top-down/bottom-up) and their integration, data availability for calibration and validation, model scale, and uncertainty. Possible future changes of biofuel land use and research gaps and limitations are synthesized. Key issues are the lack of data for independent validation and the need for better integration of dynamic bottom-up models into the top-down policy analysis. More research is needed to deal with the large-scale introduction of second-generation biofuel crops required. The paper culminates in describing how models can help to meet the challenge of supplying more fuel from lignocellulosic crops ( LCC) in ways that reduce indirect land-use change ( iLUC) and how such transition could be implemented in policy and practice. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]