Are biofuels really 'green' as they claim to be? This subject has come up before on this blog, usually on the side of 'no'.
A recent piece of correspondence to Nature (caution: paywall) from two scholars at the Federal University of Alagoas in Brazil points out the real costs associated with Brazil's experiment in sugarcane farming for bioethanol. Brazil was a pioneer in using sugar for vehicular fuel, decades before biofuels became fashionable in the rest of the world. They say that over 85% of the rainforest cover in the state of Alagoas in Brazil has been destroyed over the period of 35 years, since the beginning of the sugarcane to biofuel program. The loss of rainforest cover is thought to be responsible for landslides and flooding associated with heavy rains.
They call it "a dirty footprint in one of Brazil's poorest states." Biofuels gained popularity because they are supposedly 'renewable', as opposed to finite fossil fuels. Nothing comes for free, however, and this small planet we live on has only limited land available. For fuel crops to be grown, additional forested land has to be cleared, or land that would otherwise have grown food crops have to be converted. The former causes a net carbon gain to the atmosphere as well as a loss of biodiversity. The latter straitens the food supply, risking higher prices and endangering vulnerable populations.
There's no way to win!