Study: Ethanol may add to global warming

WASHINGTON -- The widespread use of ethanol from corn could result in nearly twice the greenhouse gas emissions as the gasoline it would replace because of expected land-use changes, researchers concluded Thursday. The study challenges the rush to biofuels as a response to global warming.

The researchers said that past studies showing the benefits of ethanol in combating climate change have not taken into account almost certain changes in land use worldwide if ethanol from corn — and in the future from other feedstocks such as switchgrass — become a prized commodity.

"Using good cropland to expand biofuels will probably exacerbate global warming," concludes the study published in Science magazine.

The researchers said that farmers under economic pressure to produce biofuels will increasingly "plow up more forest or grasslands," releasing much of the carbon formerly stored in plants and soils through decomposition or fires. Globally, more grasslands and forests will be converted to growing the crops to replace the loss of grains when U.S. farmers convert land to biofuels, the study said.

The Renewable Fuels Association, which represents ethanol producers, called the researchers' view of land-use changes "simplistic" and said the study "fails to put the issue in context."

"Assigning the blame for rainforest deforestation and grassland conversion to agriculture solely on the renewable fuels industry ignores key factors that play a greater role," said Bob Dinneen, the association's president.

There has been a rush to developing biofuels, especially ethanol from corn and cellulosic feedstock such as switchgrass and wood chips, as a substitute for gasoline. President Bush signed energy legislation in December that mandates a six-fold increase in ethanol use as a fuel to 36 billion gallons a year by 2022, calling the requirement key to weaning the nation from imported oil.

The new "green" fuel, whether made from corn or other feedstocks, has been widely promoted — both in Congress and by the White House — as a key to combating global warming. Burning it produces less carbon dioxide, the leading greenhouse gas, than the fossil fuels it will replace.