SSS 2008-02-11（在线收听）

This is Scientific American's 60-Second Science. I am Karen Hopkin, this'll just take a minute.

For years, advocates have touted the use of biofuels as a clean burning alternative to gasoline, now a pair of studies published in the Feb 8 issue of Science conclude that biofuels may do more harm to the environment than good.

The researchers calculated the indirect costs of growing the crops that turned into biofuels. To plant the corn or sugarcane or soybeans from which bio-diesel and bio-ethanol are made, farmers were first need to clear forest and grasslands. That process it turns out would actually generate more carbon dioxide than we save by swearing off fossil fuels and would take centuries for us to pay off that carbon debt. For example, the scientists figured it would take 319 years of using ethanol made from soybeans to make up for the extra carbon released by chopping down the forests needed to grow the crop. And of course more CO2 in the atmosphere means more global warming. So Biofuels might actually exacerbate the problem they are meant to solve. Something to think about as we move forward on producing eco-friendly fuels, as one of the scientists put it, we should make sure that our cure isn't worse than the disease.

Thanks for the minute, for Scientific American's 60-Second Science. I am Karen Hopkin.