Study: Biofuels Reduce Carbon but Cause Other Problems
The study compares 25 fossil, methane, ethanol, and biodiesel fuels on 16 environmental impacts, including global warming potential (GWP), acidification, ozone depletion, human carcinogenicity, and land use. All score better than gasoline on ozone depletion, and all but Brazilian soy score better than gasoline for GWP.
The worst offender is intensively grown Jatropha from India, with impacts significantly greater than gasoline in 11 categories including freshwater ecotoxicity and human cancer effects. Expanding production of palm oil, a major cause of deforestation, is expected to release more than 558 million metric tons of carbon in 2020—more than the entire nation of Canada.
The best overall scores were for methane gas derived from wood chips, manure, and sewage sludge. Ethanol can also score well, depending on its production methods: the authors warn against clearing forests for “energy plants” or, indirectly, for food production displaced by a transition to such plants elsewhere.
Published October 26, 2012