Renewable fuels such as ethanol have long been hailed as a cleaner-burning alternative to fossil fuels and a potent way to reduce the climate-changing gases pumped out of car tailpipes.
The 2007 Energy Act signed by President Bush last December doubles the nation's use of corn-based ethanol. Ethanol production in Minnesota, a pioneer of the technology, is expected to double during the next three years.
But research by Minnesota scientists is challenging the underpinnings of the biofuel rush. Ethanol and similar products may do more harm than good because of the changes they bring to the landscape, some scientists say.
The exploding demand for ethanol, soy diesel and other products is causing farmers to clear forests, grasslands and peat lands on a massive scale, unleashing far more carbon dioxide than is saved by the lower emissions of the biofuels, the study said.
"If we keep moving to get large amounts of energy by growing it on newly cleared land, which is what's happening around the world, we're going to be releasing much more greenhouse gas than the benefits we get from those biofuels," said David Tilman, ecology professor at the University of Minnesota and one of the study's authors.
The study, published Thursday in the online version of the journal Science, was funded by the National Science Foundation and the University of Minnesota. Another study published Thursday in Science, with estimates from economists at Iowa State University, concluded that corn-based ethanol could double greenhouse gas emissions, rather than reducing them, during the next 30 years because of the dramatic changes in land use.
From another more in-depth article:
I am sure that the ethanol industry is a godsend to the many farmers who are growing corn and actually making some money. And I am sure a similar scenario is playing out in other countries where palm and soy bean plants are replacing grasses and forests. But it is difficult to justify from any other environmental or economic perspective.
The land-use issue makes the balance sheet far more problematic: The clearance of grassland releases 93 times the amount of greenhouse gas that would be saved by the fuel made annually on that land, said Joseph Fargione, the lead author of the other study and a scientist at the Nature Conservancy. "So for the next 93 years, you're making climate change worse, just at the time when we need to be bringing down carbon emissions."