Ethanol’s Broken Promise: Using Less Corn Ethanol Reduces Greenhouse Gas Emissions
It is now clear that the federal corn ethanol mandate has driven up food prices, strained agricultural markets, increased competition for arable land and promoted conversion of uncultivated land to grow crops. In addition, previous estimates have dramatically underestimated corn ethanol's greenhouse gas emissions by failing to account for changes in land use.
In 2012, an Environmental Working Group study found that from 2008 to 2011, more than 8 million acres of grassland and wetlands were converted for corn alone. EWG's new analysis shows that these land use changes resulted in annual emissions of 85 million to 236 million metric tons (CO2e) of greenhouse gases. In light of these emissions, many scientists now question the environmental benefit of so-called biofuels produced by converting food crops. A few recent studies still claim that corn ethanol produces fewer emissions than gasoline, but a careful look reveals that their methods don't properly account for land use change. Studies that do factor in land use change show that using food crops to produce biofuels - once considered a promising climate change mitigation strategy - is worse for the climate than gasoline.