New study casts doubt on ethanol's climate benefits

A new study is casting doubt on the climate benefits of using ethanol as a fuel, finding that it may actually contribute more to global warming than gasoline.

Researchers found that emissions from changes in land use to account for the growing demand for corn make corn-based ethanol no cleaner than gasoline.

In fact, they determined that these changes likely make ethanol's emissions at least 24 percent higher than those for gasoline, according to their study, which was published in the Proceedings of the National Academy of Sciences.

A 2005 law established what's known as the "Renewable Fuel Standard" requiring a certain quantity of biofuels, a category that includes ethanol, to be blended into gasoline.

Under that law, the Environmental Protection Agency (EPA) annually sets standards for the amount of biofuels that need to be blended in.

Study author Tyler Lark said his findings suggest that the agency should not increase blending requirements, saying it would "likely result in greater greenhouse gas emissions."

The findings differ from prior studies which found that ethanol was more climate-friendly than gasoline, like a study from the Agriculture Department which found that ethanol contributed between 39 and 43 percent less to climate change.

Lark said that unlike past findings, the latest study was able to use new information to look at what happened retroactively, instead of using models of future changes.

It's also not the first study to suggest that biofuels are not so climate friendly. A 2008 study determined that over a 30-year period, biofuels could cause twice as much carbon dioxide to be released as gasoline when global impacts are considered.