In the debate on the future of transport biofuels, environmental matters have also become important. Slowing down climate change is often mentioned as an impor­tant reason for expanding the use of biofuels, as CO2 that is released on burning this biomass is supposed to be rapidly sequestered again by re-growth of biomass. How­ever, this is not the whole story. Because fossil fuels are used for powering biofuel production, biofuel production may be associated with the emission of greenhouse gases other than CO2, such as N2O and CH4, and biofuel production can be associ­ated with changes in the carbon content of ecosystems. Thus, a lively discussion has originated on whether promoting transport biofuels does indeed slow down climate change. And there is a longstanding discussion as to whether the overall environ­mental impacts of biofuels are positive (e. g. Healy 1994), which has focused on the impacts of agricultural chemicals used in biomass production and water use. Also, the impact of transport biofuel production on nature has emerged as an issue. In particular, the importation by industrialized countries of palm oil from Southeast Asia, of biofuels from South America and the cutting of tropical forests for the es­tablishment of biofuel plantations in Africa have sparked a debate on the impact of transport biofuels on living nature. In turn, environmental concerns contribute to the emergence of regulations and certification schemes that aim to address such concerns (Mathews 2008b; van Dam et al. 2008).