The "Dark Side" of Sugar-Cane Ethanol Production

CO2 Science
Reviewed 4 July 2012


Reference
Tsao, C.-C., Campbell, J.E., Mena-Carrasco. M., Spak, S.N., Carmichael, G.R. and Chen, Y. 2011. Increased estimates of air-pollution emissions from Brazilian sugar-cane ethanol. Nature Climate Change 2: 53-57.

Background
The authors write that "accelerating biofuel production has been promoted as an opportunity to enhance energy security, offset greenhouse-gas emissions and support rural economies." However, they indicate that "air-pollutant emissions from biofuel production and combustion may have significant impacts on climate and air quality," and that "the change in vehicle emissions that would result from a large-scale conversion from gasoline to E85 (a blend of up to 85% ethanol with gasoline or another hydrocarbon) in the United States could have significant health consequences, by increasing tropospheric ozone concentrations," citing Jacobsen (2007). And they add that Hill et al. (2009) have also demonstrated that "the use of corn ethanol has higher health costs than gasoline."

What was done
Noting that that sugar-cane ethanol is one of the most widely used biofuels, and that Brazil is its largest producer, Tsao et al. developed a set of spatially and temporally explicit estimates of air-pollutant emissions - including volatile organic compounds, nitrogen oxides, particulate matter less than 10 and 2.5 µm in diameter, sulfur oxides and carbon monoxide - over the entire life cycle of sugar-cane ethanol as produced in Brazil.

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