32
2 The Contested Sustainability of Biofuels …
2008; Butler and Laurance 2008). Moreover, most areas suitable for feedstock agriculture are near biodiversity hotspots (e.g., the Cerrado in Brazil, Southeast Asia’s
rainforest), heightening the risks (Koh 2007). Finally, biofuel production expansion
occurs largely in the developing world, where infrastructure, monitoring capacity,
and funds available for conservation programs are limited. As such, the implementation of ecosystem protection strategies tends to become even more challenging (see
Boyd 2008; Bastos Lima 2018). Biofuels might thus be intensifying pressures on
particularly sensitive areas that are both valuable and vulnerable.
Given this pressure on biodiversity, there have been many estimations of how much
land could be sustainably used for biofuels (see Hoogwijk et al. 2003; Cai et al. 2011).
For decades this has been an object of debate. Some indicate that an additional 250–
800 Mha of rain-fed land are available, most of it in Africa and Latin America (Fischer
2008), while others suggest more than 1100 Mha available, combining pasturelands,
idle lands, and grass and shrublands of marginal productivity (Cai et al. 2011). These
broad estimates tend to assume a more extensive use of feedstocks that can grow on
marginal soils and under water stress, such as jatropha or perennial grasses used for
cellulosic ethanol production (see Achten et al. 2008; Tilman et al. 2006). However,
the Food and Agriculture Organization of the United Nations (FAO) has warned that
yields on such lower-quality lands are also expected to be low. Therefore, it may
not be commercially viable in some cases (FAO 2008, p. 67). Besides, many authors
have asked for caution when looking at those estimates of land availability that do
not consider social and political aspects (Rhodes and Keith 2008; Cotula et al. 2008).
The impacts of biofuel production on land and biodiversity also largely depend on
the agricultural system being promoted. It is well known, for instance, that chemicalintensive monocultures degrade the soil and reduce its fertility and biodiversity (Ye
and Van Ranst 2009; Tilman et al. 2002). Regardless of its purpose, such conventional
industrial agriculture has created serious ecological problems through nitrogen deposition, soil acidification, ecosystem eutrophication, and habitat contamination from
toxic chemicals used as pesticides (Altieri 2000; Tilman et al. 2002). Those contaminants are directly detrimental to human health (WHO 1990). Moreover, industrial
agriculture has severely eroded agrobiodiversity, which is crucial for maintaining
ecosystem services and the very genetic base on which crop breeding depends (Altieri
2000; Tilman et al. 2002; FAO 2004). Biofuels may, therefore, add to those impacts
if they are produced under such conventional systems (Bastos Lima 2018). It may
also aggravate soil degradation in case crop residues are taken as feedstocks, as
this would reduce the availability of organic matter (Muller 2009; Langeveld et al.
2010a). In a comparison among crops, sugarcane tends to perform somewhat better
than corn, soybean or rapeseed, partly because sugar-mill and distillery wastes typically are used to help replenish soil nutrients (IEA 2006, p. 393). Also, sugarcane
requires less pesticide use than corn or soybean cultivation, and it also causes less
soil erosion (Goldemberg et al. 2008). Generally, agricultural practices such as crop
rotation, riparian vegetation maintenance, and conservation tillage or no-till agriculture can improve environmental performance. However, these techniques just reduce
impacts; they do not eliminate them (Robertson et al. 2008).
2 The Contested Sustainability of Biofuels …
2008; Butler and Laurance 2008). Moreover, most areas suitable for feedstock agriculture are near biodiversity hotspots (e.g., the Cerrado in Brazil, Southeast Asia’s
rainforest), heightening the risks (Koh 2007). Finally, biofuel production expansion
occurs largely in the developing world, where infrastructure, monitoring capacity,
and funds available for conservation programs are limited. As such, the implementation of ecosystem protection strategies tends to become even more challenging (see
Boyd 2008; Bastos Lima 2018). Biofuels might thus be intensifying pressures on
particularly sensitive areas that are both valuable and vulnerable.
Given this pressure on biodiversity, there have been many estimations of how much
land could be sustainably used for biofuels (see Hoogwijk et al. 2003; Cai et al. 2011).
For decades this has been an object of debate. Some indicate that an additional 250–
800 Mha of rain-fed land are available, most of it in Africa and Latin America (Fischer
2008), while others suggest more than 1100 Mha available, combining pasturelands,
idle lands, and grass and shrublands of marginal productivity (Cai et al. 2011). These
broad estimates tend to assume a more extensive use of feedstocks that can grow on
marginal soils and under water stress, such as jatropha or perennial grasses used for
cellulosic ethanol production (see Achten et al. 2008; Tilman et al. 2006). However,
the Food and Agriculture Organization of the United Nations (FAO) has warned that
yields on such lower-quality lands are also expected to be low. Therefore, it may
not be commercially viable in some cases (FAO 2008, p. 67). Besides, many authors
have asked for caution when looking at those estimates of land availability that do
not consider social and political aspects (Rhodes and Keith 2008; Cotula et al. 2008).
The impacts of biofuel production on land and biodiversity also largely depend on
the agricultural system being promoted. It is well known, for instance, that chemicalintensive monocultures degrade the soil and reduce its fertility and biodiversity (Ye
and Van Ranst 2009; Tilman et al. 2002). Regardless of its purpose, such conventional
industrial agriculture has created serious ecological problems through nitrogen deposition, soil acidification, ecosystem eutrophication, and habitat contamination from
toxic chemicals used as pesticides (Altieri 2000; Tilman et al. 2002). Those contaminants are directly detrimental to human health (WHO 1990). Moreover, industrial
agriculture has severely eroded agrobiodiversity, which is crucial for maintaining
ecosystem services and the very genetic base on which crop breeding depends (Altieri
2000; Tilman et al. 2002; FAO 2004). Biofuels may, therefore, add to those impacts
if they are produced under such conventional systems (Bastos Lima 2018). It may
also aggravate soil degradation in case crop residues are taken as feedstocks, as
this would reduce the availability of organic matter (Muller 2009; Langeveld et al.
2010a). In a comparison among crops, sugarcane tends to perform somewhat better
than corn, soybean or rapeseed, partly because sugar-mill and distillery wastes typically are used to help replenish soil nutrients (IEA 2006, p. 393). Also, sugarcane
requires less pesticide use than corn or soybean cultivation, and it also causes less
soil erosion (Goldemberg et al. 2008). Generally, agricultural practices such as crop
rotation, riparian vegetation maintenance, and conservation tillage or no-till agriculture can improve environmental performance. However, these techniques just reduce
impacts; they do not eliminate them (Robertson et al. 2008).