Some hail ethanol as the methadone needed to wean Western countries off fossil fuels. Others deplore it as environmental sabotage.
The effects of Brazil’s growing sugarcane industry have prompted scientists to ask the question: are biofuels sustainable?
Prof. Luiz Martinelli, ecology, University of São Paulo in Brazil, presented his assessment of Brazilian biofuels on Friday.
In 2008, he published a divisive article in the journal, “Ecological Applications.”
“I published a paper just summarizing what was the environmental and social aspects of the sugar cane industry. And a lot of people [got] really mad at me, and this … incentivated me to continue studying sugar cane growers,” he explained. Ever since, Martinelli has refined his assessment of the overall impact of sugarcane ethanol on his country.
Martinelli opened the seminar with a picture of Brazilian president Luiz Inacio Lula da Silva and former U.S. president George Bush. In the photo, the leaders of the two largest biofuel-producing countries in the world donned matching biodiesel company hardhats. Martinelli used the photograph to underscore the role of government in biofuel production in both countries.
In Brazil, the government has strongly promoted the production of sugarcane ethanol in the country with its national alcohol program, Proalcool, for the past 30 years. Law mandates that all gasoline must contain at least 20% ethanol, and the government artificially lowers the price of ethanol below the price of gas at fuel stations.
According to Martinelli, ethanol production and land-use disturb the environment.
To make ethanol, yeast cells are added to vats of sugar cane juice, producing a liquid product that contains about 6-11% ethanol. This liquid is distilled, and nearly pure ethanol is collected. The remaining sludge from the distillation is collected, forming a thick by-product, called “vinasse.” For every liter of ethanol produced, 10 liters of vinasse are also made.
Growers spread the vinasse liquid back on their crop as a fertilizer. The nutrient content makes vinasse a good fertilizer.
However, this nutrient content pollutes the streams and rivers near the sugarcane mills. The increased nitrogen and organic carbon in the vinasse kills fish and disrupts aquatic systems. Mill owners claim vinasse management isn’t a problem, Martinelli pointed out, “Accidents do happen because you are transporting large amount of vinasse.”
Burning is another growing practice associated with negative long-term effects. Martinelli joked, “Brazilians are really pyromaniacs. We burn the Amazon. We burn sugar cane. We burn everything.”
Sugar cane growers use fires to burn the leaves and straw, making harvest easier. Repeated burning, however, leads to soil erosion and soil compaction. Fire also releases aerosolized particles into the air, which are harmful to nearby residents. Martinelli suggests expansion of sugarcane land may increase respiratory problems in young and elderly Brazilian.
Ethanol production fosters deforestation in Brazil. Sugarcane needs a well-defined drought season to concentrate sugars in the cane stalk, making the wetter Amazon region less than ideal for growth. Consequently, growers convert increasing areas of land in the transitional area between the cerrado grasslands and the Amazon forests to sugarcane. As a result, the increase may indirectly lead to deforestation as other crops, like soybean, are pushed into the Amazon.
“We don’t have much room for deforestation. If sugarcane causes 1,000 of squared kilometers of deforestation, we’ve set off any savings [of avoided carbon emissions] that we have saved,” emphasized Martinelli.
Martinelli favors other solutions to rising carbons levels, saying, “If you think that your cars are inefficient in terms of gasoline use, our cars are much more inefficient than yours … If we increase the fuel efficiency of the Brazilian car by 20-30%, we would save the same amount of the ethanol savings [as ] carbon emissions.”
According to Martinelli, “Agriculture is a valid way to develop a country, but not the way that we are doing with sugarcane. I hope I have proved to you that ethanol is good for economical growth but it is not bringing economical development. It is not saving the world. It’s concentrating more money in fewer hands, and more land in fewer hands.”