H. Josef Hebert, Associated Press Yahoo News 8 Feb 08;
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.
During the recent congressional debate over energy legislation, lawmakers frequently cited estimates that corn-based ethanol produces 20 percent less greenhouse gases in production, transportation and use than gasoline, and that cellulosic ethanol has an even greater benefit of 70 percent less emissions.
The study released Thursday by researchers affiliated with Princeton University and a number of other institutions maintains that these analyses "were one-sided" and counted the carbon benefits of using land for biofuels but not the carbon costs of diverting land from its existing uses.
"The other studies missed a key factor that everyone agrees should have been included, the land use changes that actually are going to increase greenhouse gas emissions," said Tim Searchinger, a research scholar at Princeton University's Woodrow Wilson School of Public and International Affairs and lead author of the study.
The study said that after taking into account expected worldwide land-use changes, corn-based ethanol, instead of reducing greenhouse gases by 20 percent, will increases it by 93 percent compared to using gasoline over a 30-year period. Biofuels from switchgrass, if they replace croplands and other carbon-absorbing lands, would result in 50 percent more greenhouse gas emissions, the researchers concluded.
Not all ethanol would be affected by the land-use changes, the study said.
"We should be focusing on our use of biofuels from waste products" such as garbage, which would not result in changes in agricultural land use, Searchinger said in an interview. "And you have to be careful how much you require. Use the right biofuels, but don't require too much too fast. Right now we're making almost exclusively the wrong biofuels."
The study included co-authors affiliated with Iowa State University, the Woods Hole Research Center and the Agricultural Conservation Economics. It was supported in part indirectly by a grants from NASA's Terrestrial Ecology Program, and by the William and Flora Hewlett Foundation. Searchinger, in addition to his affiliation with Princeton, is a fellow at the Washington-based German Marshall Fund of the United States.
The study prompted a letter Thursday to President Bush and Democratic and Republican leaders in Congress from nearly a dozen scientists who urged them to pursue a policy "that ensures biofuels are not produced on productive forests, grassland or cropland."
"Some opportunities remain to produce environmentally beneficial biofuels" while "unsound biofuel policies could sacrifice tens of hundreds of million of acres" of grasslands and forests while increasing global warming, said the scientists, including four members of the National Academy of Sciences.
Food-Based Biofuels Can Spur Climate Change - Study
Deborah Zabarenko, PlanetArk 8 Feb 08;
WASHINGTON - Alternative fuels made from corn, soybeans, sugarcane and palm trees can in some cases increase the amount of climate-warming carbon dioxide that goes into the atmosphere, US researchers reported on Thursday.
These so-called food-based biofuels can actually hurt the environment if they are produced on land that was formerly grassland, rainforest or savanna, the scientists said in the journal Science.
Nonfossil fuels -- ethanol made from corn or sugarcane and biodiesel made from palm trees or soybeans -- are meant to lessen dependence on petroleum products, which release the greenhouse gas carbon dioxide when they burn.
However, biofuels can release carbon even before they are burned, depending on how they are made, said study co-author Jason Hill of the University of Minnesota.
As demand for these alternative fuels grows, farmers are plowing under forests and grasslands that used to store carbon and keep it from getting into the atmosphere, and using these lands to grow the food crops that now can be used for ethanol or biodiesel.
Biofuels grown this way come with a "carbon debt," the researchers found. Instead of cutting greenhouse pollution, the net effect is to increase it.
The carbon lost by converting rainforests, peatlands, savannas and grasslands outweighs the carbon savings from biofuels. Some conversions release hundreds of times more carbon than the annual savings from replacing fossil fuels.
CENTURIES OF CARBON DEBT
For example, the scientists wrote, Indonesia's conversion of peatlands for palm oil plantations had the world's greatest carbon debt, one that would take 423 years to repay.
The next worst case was the planting of soybeans in the Amazon, which would not pay for itself in renewable soy biodiesel for 319 years.
There are biofuel sources that do not rack up these formidable carbon debts, Hill said: nonfood plants including perennial grasses that only have to be harvested, without plowing under existing species that hold on to carbon.
"Our group has looked at using diverse mixtures of native species ... (on) prairie land, land that's restored back into prairies," Hill said in a telephone interview. "We essentially have no native prairies left in this nation but we can restore land into prairies, thereby restoring an ecosystem that was natural and also getting the biofuel benefit from it."
Biofuels, whether made from prairie plants, corn or soybeans, lack the potential to satisfy US fuel needs, Hill said.
"If we take every corn kernel we produce in this nation and convert it to ethanol, we would offset only 12 percent of our gasoline use," he said. "And that doesn't include the energy it took to produce that ethanol in the first place.
"None of these are solutions, but we better be sure we're not making the problem worse, and that's what's happening with the current generation of food-based biofuels," Hill said. (Editing by Xavier Briand)
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