By the beginning of 2008, the share of transport biofuels in the worldwide consump­tion of transport fuels was below 1%, and land use for transport biofuels was esti­mated at 13.8 Mha in the USA, Brazil, China and the EU (Renewable Fuels Agency 2008), but significant upward impacts on the conversion of nature into cropland could be noted (OECD-FAO 2007; Nepstad et al. 2008; Chap. 5). Current policy targets for the expansion of transport biofuel production have been estimated to re­quire between 55 and 166 Mha land (Renewable Fuels Agency 2008). Such a major further expansion of transport biofuel production will (ceteris paribus) stimulate the conversion of nature into cropland (Searchinger et al. 2008; Sukhdev 2008).

Moreover, as indicated in Chaps. 2 and 5, it is to be expected that part of a further expansion of transport biofuel production will come from intensification of agricul­ture. Intensification of agriculture is expected to be associated with higher inputs of nutrients and pesticides and increased irrigation and drainage (Tilman et al. 2001; Datta et al. 2004; Tscharntke et al. 2005; Liira et al. 2008). This, in turn, is expected to lead to a decline in biodiversity among many taxa and a loss of ecosystem services (Tscharntke et al. 2005; Liira et al. 2008).

When, unlike current practice, low-quality land is used for the expansion of bio­fuel production (as suggested in Sects. 6.3 and 6.5) and there is a fixed amount of transport biofuel to be produced, such as mandated under several current regula­tions, then — in view of the probably relatively low productivity of the land — larger areas will be needed than in the case of the use of good-quality land. Moreover, as pointed out in Chap. 5, abandoned and fallow lands by themselves rather often har­bour substantial biodiversity. When such relatively biodiverse abandoned and fallow agricultural lands are exploited, the negative impact on biodiversity may be large (Huston and Marland 2003; Marland and Obersteiner 2008). On the other hand, as pointed out in Chap. 5, there are also fallow and abandoned agricultural lands with relatively low biodiversity, such as parts of the Imperata cylindrica and Saccharum spontaneum grasslands, which may be exploited for transport biofuel production with a relatively low impact on biodiversity.

The size of the impact of expanding transport biofuel production is also depen­dent on other factors. Effects on biodiversity would, for example, be relatively large when current hotspots of biodiversity, such as tropical rainforests, the Cerrado sa­vannah or nature in the Cape region of South Africa (Darkoh 2003; Koh 2007; Danielsen et al. 2008), are converted into land for the production of transport biofuel feedstocks. Also, if precision agriculture and water-efficient irrigation techniques are used for the expansion of feedstock production (cf. Sects. 3.4 and 4.6), the im­pact thereof on biodiversity may well be lower than in the case of conventional practices, because water consumption and the emissions of nutrients and pesticides may be lower.

Though the impact of a maj or expansion of transport biofuel production on living nature may be variable, there would seem to be no scope for a major expansion of biofuel production in such a way that biodiversity loss will be zero. It is likely that a major expansion of transport biofuel production will have a major negative effect on biodiversity and ecosystem services.