It seems that global warming could be worsened by destroying native ecosystem for biofuel crops.
According to the study, conducted by the University of Minnesota and the Nature Conservancy, though biofuels are meant to mitigate the effects of globa warming, turning native ecosystems into farms for biofuel crops causes major carbon emissions, that has the opposite effect on the environment.
The carbon lost by converting rainforests, peatlands, savannas, or grasslands outweighs the carbon savings from biofuels, the report indicated.
Such conversions for corn or sugarcane (ethanol), or palms or soybeans (biodiesel) release 17 to 420 times more carbon than the annual savings from replacing fossil fuels, the researchers said.
"This research examines the conversion of land for biofuels and asks the question 'Is it worth it'," said lead author Joe Fargione, a scientist for The Nature Conservancy. "And surprisingly, the answer is no," he added.
According to Farigone, "If you're trying to mitigate global warming, it simply does not make sense to convert land for biofuels production."
"All the biofuels we use now cause habitat destruction, either directly or indirectly. Global agriculture is already producing food for six billion people. Producing food-based biofuel, too, will require that still more land be converted to agriculture," he explained.
The carbon, which is stored in the original plants and soil, is released as carbon dioxide, a process that may take decades. This "carbon debt" must be paid before the biofuels produced on the land can begin to lower greenhouse gas levels and ameliorate global warming.
The conversion of peatlands for palm oil plantations in Indonesia ran up the greatest carbon debt, one that would require 423 years to pay off. The next worst case was the production of soybeans in the Amazon, which would not "pay for itself" in renewable soy biodiesel for 319 years.
The researchers also found significant carbon debt in the conversion of grasslands in the United States and rainforests in Indonesia.
"Creating some sort of incentive for carbon sequestration, or penalty for carbon emissions, from land use is vital if we are serious about addressing this problem," said University of Minnesota Applied Economics professor Stephen Polasky, an author of the study.