Sugarcane is touted as the miracle biofuel even by biofuels' skeptics.
Former President Bill Clinton lauded it at the recent Brazilian ethanol summit, held in São Paulo (although he warned of the dangers of deforestation). Sweden views sugarcane ethanol as a relatively clean proxy for petroleum and has sought to lower EU import tariffs on it, the better to have a more "renewable" energy profile.
By some measures, sugarcane ethanol deserves the accolades.
The governing metric for determining the quality of a given biofuel is the EROEI, or the energy returned on energy invested. For Brazilian sugarcane ethanol, the number is frequently reported as eight or higher—that is, for every unit of fossil energy input, eight units of sugarcane ethanol energy are output. Pretty good.
Except for a niggling problem: The ecology is a bit more complicated than an EROEI calculation. For one thing, a recent study in the journal Science suggests that conversion from rainforests, peat-lands, savannas or grasslands to biofuel plantations can create huge carbon debts that will take decades to repay:
Sugarcane ethanol produced on Cerrado sensu stricto (including Cerrado aberto, Cerrado densu, and Cerradão), which is the wetter and more productive end of this woodland-savanna biome, would take 17 years to repay the biofuel carbon debt.
The cerrado covers 20 percent of the Brazilian landmass, and is home to 10,000 plant species, close to one thousand bird species, and several hundred species of mammals. Such bio-diversity will not bear a massive bio-fuels land-grab without getting pummeled.
The study's authors, from the University of Minnesota and The Nature Conservancy, restricted their analyses to the cerrado, because it's commonly asserted that sugarcane cultivation isn't taking place in the Amazon. Asserted incorrectly. Brazil's National Commodities Supply Corp notes that from 2007 to 2008, Amazonian sugarcane production increased from 17.6 to 19.3 million tons.
As researcher Écio Rodrigues from the Federal University of Acre comments,
"Carbon dioxide released from the destruction of forests cannot be compensated by cane production. This is why everybody is worried about Brazil's transformation into a biofuel superpower."
Furthermore, the fields of cane envisioned by sugarcane ethanol advocates and planted by sugarcane ethanol magnates are very, very big, and they're monocultures. Such monocultures need constant chemical treatment simply to stave off fungi growth and pest infestations, causing pesticide run-off, pollution of underground water resources—in Brazil deleteriously affecting the Guarani aquifer—and soil erosion, because sugarcane planted for ethanol production is ripped off at the roots, ensuring that little of the carbon from the plant can return to the soil.
There are also other ecological costs: Brazilian geographer Ariovaldo Umbelino de Olivera comments that sugarcane has caused corn and black-bean production in Brazil to decline by 10 percent in recent years, because they are planted on land prone to flooding, land that sugarcane is increasingly occupying. The cane-crop displaces other cash-crops toward the cerrado and the Amazon (both regions where cane is anyway cultivated) thereby contributing to deforestation and carbon emissions.
Additionally, according to journalist Philippe Revelli, the method of preparing the cane for cutting is disastrous: The leaves are burnt off the cane stalks, making hand-harvesting easier and increasing the plant's sucrose count. This releases great quantities of toxic particles, carbon monoxide, and greenhouse gases, as well as a layer of ash that litters São Paulo state.
Furthermore, horrific working conditions on sugarcane plantations are systemic. As Brazilian sociologist Maria Aparecida de Moraes Silva comments, cane workers are paid by the quantity harvested:
They work eight not nine hours daily, intensely, from Monday to Saturday. They lose six kilos over the course of the harvest and required to cut, minimally, 12 tons of cane. Cutting 10 tons requires 9,700 cuts, under intense heat, wearing pants, ankle protectors, shoes, gloves, long-sleeves shirts, and hats with scarves.
This is the miracle agro-fuel?