Are biofuels earth-friendly?

Two recent studies in the journal Science argue that biofuels like ethanol might contribute to global warming. As the U.S. looks increasingly at alternatives to fossil fuel, how much should we rely on biofuels?

Joe Fargione: Regional science director for the Nature Conservancy.

Timothy Searchinger: Researcher at the Woodrow Wilson School of Public and International Affairs at Princeton University.

Bill Lee: General manager of the Chippewa Valley Ethanol Company in Benson, MN. He is the former chairman of the Renewable Fuels Association.