U.S. experts warn that rules governing biofuel production encourage deforestation and mean the technology is therefore a "false" method of reducing greenhouse gas emissions.
In a study to published on Oct. 23 in the journal Science, a group of 13 scientists called for the rules, which contain a loophole exempting carbon dioxide emitted by bioenergy regardless of its source, to be overturned.
"The error is serious, but readily fixable," said lead researcher Timothy Searchinger of Princeton University.
The study called for the issue to be addressed in the climate treaty that nations around the world are hoping to sign at the Copenhagen summit in December to supercede the Kyoto Treaty.
Researchers said numerous analyses -- including one released by the U.S. Department of Energy -- have found that this loophole "could lead to the loss of most of the world's natural forests as carbon caps tighten."
The rules were found in the Kyoto Protocol, which was framed in 1997 and put into force in 2005, legally binding 37 industrialized countries to cut their greenhouse gas output, noted researcher Daniel Kammen.
The European Union's Emissions Trading System and this year's climate bill passed by U.S. House members also enable the same loophole, said Kammen, from the University of California in Berkeley.
The study said it meant that "bioenergy from any source, even that generated by clearing the world's forests, a potentially cheap, yet false, way to reduce greenhouse gas emissions."
Research released by the World Wildlife Fund on Thursday found that 13 million hectares (32.1 million acres) of forests are destroyed around the world each year -- equivalent to 36 football fields per minute. Deforestation generates almost 20% of global greenhouse gas emissions, said the environmental group.
"Halting forest loss has been identified as one of the most cost-effective ways to keep the world out of the danger zone of runaway climate change," the group said. Those that benefit most from the loophole are oil companies, power plants and other energy industry firms producing biofuels who engage in deforestation in response to tighter limits on pollution.
Kammen said nations approaching climate treaty negotiations needed to recognize the "vital" importance of properly evaluating technologies proposed as solutions to global warming.
In another study on the subject published in Science Express on Oct. 22, researchers noted how no major countries involved in climate negotiations take into account carbon emissions arising from land-use changes for harvesting biofuels. Not only is there little oversight to how biofuel is developed, said the study, led by Marine Biological Laboratory (MBL) scientist Jerry Melillo, the economic incentives for biofuels to be developed on land reclaimed from forests "add to the climate-change problem rather than helping to solve it."
The study, Melillo added, "shows that direct and indirect land-use changes associated with an aggressive global biofuels program have the potential to release large quantities of greenhouse gases to the atmosphere."
Burning bioenergy and fossil energy release comparable quantities of carbon dioxide. But in a key difference, bioenergy has been seen as preferable for combating climate change because overall emissions are -- in theory -- reduced, because biomass results from additional plant growth.
"This is because plants grown specifically for bioenergy absorb carbon dioxide from the atmosphere, and this offsets the emissions from the eventual burning of the biomass for energy," said the study, adding that in contrast, burning forests releases stored carbon in the same way as burning oil.
However, both the studies note, the positive effect of biofuels on carbon emissions would necessarily be negated if land used to produce them had been cleared of forests to do so.
Melillo's study also predicts the increased use of fertilizer in biofuels production will cause nitrous oxide emissions to become even more important than carbon losses in terms of potential for warming by the end of the century.
Copyright Agence France-Presse, 2009