The production and use of biofuels such as ethanol would contribute to global warming more than simply using gasoline, according to two studies published in the journal Science.
One study, conducted by a scientist from the Nature Conservancy and researchers from the University of Minnesota, concluded that the conversion of the Southeast Asian or Latin American grasslands, savannas, peatlands or forests into biofuel plantations would result in a net increase in greenhouse gas levels for decades or even centuries.
Biofuels are often touted as being “carbon neutral,” because the carbon released by burning them is supposedly the same as the carbon they removed from the atmosphere while growing. Yet clearing land for biofuel production destroys areas that would otherwise remove carbon without emitting any in turn.
A second related study, conducted by researchers from Princeton University, Woods Hold Research Center and Iowa State University, concluded that it would take 167 years of use before biofuels stopped contributing to global warming.
“The land we’re likely to plow up is the land that we’ve had taking up carbon for decades,” said lead author Tim Searchinger. “We can’t get to a result, no matter how heroically we make assumptions on behalf of corn ethanol, where it will actually generate greenhouse-gas benefits.”
Searchinger and colleagues noted that while their calculations used corn-based ethanol, any type of ethanol would still be worse for the climate than gasoline.
The findings come as the United States and Europe are aggressively pushing the expansion of biofuels as a solution to global warming. Spurred by the recent Science articles, a group of 10 senior climate scientists sent a letter to President Bush and U.S. congressional leaders urging them to reassess this stance.
“While politicians in the United States and Europe have tried to craft policies dictating that new biofuels will not come at the expense of clearing land, the papers show that sometimes land conversion is often an indirect result of this expansion,” the scientists wrote.
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