Indirect land-use changes can overcome carbon savings from biofuels in Brazil.
In this article the author discusses the cons of biofuels in Brazil. The major one is caused when biofuel plantations expand and replace rangelands and farmlands. This causes a soil degradation that release carbon emissions. Brazilian sugarcane productions is known to be among the best production systems that produces that least amount of carbon emission; however, soybean production is also used in making biodiesel and emits much carbon. This is caused by the replacement of already cultivated rangelands and farmlands into soybean plantations. Today 35% of soybean plantations are residing on areas that once were a rangeland. Another effect of the soybean expansion that is causing considerable harm is that these rangelands after being replaced by soybean plantations are further expanding to meet their production needs as well. As shown in Fig. 1 there has been a major expansion of forestland to soybean and forestland to rangeland caused by soybean expansion. However, the damage to forestland from sugar cane plantation expansion requires a four-year payback of use instead of fossil fuels to compensate for the emissions that are caused, but with soybean it would take at least 35 years. In the long run by 2020, sugarcane and soybean production would be responsible for 41% and 59% of the indirect deforestation of the Amazon forest. The best crop found to replace soybeans to create a low carbon and indirect deforestation would be oil palm. However large the results of the deforestation are, compared to fossil fuels these long-term damages are relatively small.
Lapola, D. M., Schaldach, R., Alcamo, J., Bondeau, A., Koch, J., Koelking, C., & Priess, J. A. (2010). Indirect land-use changes can overcome carbon savings from biofuels in Brazil. Proceedings of the national Academy of Sciences,107(8), 3388-3393.