Carbon accounting used in the Kyoto Protocol and other climate legislation currently neglects CO2 emissions from the production of biofuels, a loophole that could drive large-scale destruction of tropical forests and exacerbate global warming, warned researchers writing last week in the journal Science.
Jerry Melillo and a dozen co-authors noted that the Kyoto Protocol, the European Union’s cap-and-trade law, and the American Clean Energy and Security Act all fail to account for emissions resulting from production and use of biofuels. Instead the carbon accounting systems erroneously assume that biofuel production is carbon neutral. In reality, establishing bioenergy crops in place of carbon-dense ecosystems like tropical rainforests and peatlands results in substantial greenhouse gas emissions.
“When forests or other plants are harvested for bioenergy, the resulting carbon release must be counted either as land-use emissions or energy emissions,” said Melillo in a statement. “If this is not done, the use of bioenergy will contribute to our greenhouse gas problem rather than help to solve it.”
 Chart modified from Science. A February 2007 study published in Science showed that production of some biofuels can result in emissions greater than those from fossil fuels. The analysis looked at the lifecycle emissions from various biofuel feedstocks and presented the results as a “carbon debt” ranking. |
The authors urge policymakers to fix the the accounting flaw by establishing a system that counts all emissions, whether from fossil fuels or bioenergy. They system should also include other greenhouse gas emissions associated with bioenergy production and use, like methane and nitrous oxide.
“Bioenergy has the potential to provide a substantial amount of energy and help nations meet greenhouse caps, but correct accounting must be in place to prevent unintended consequences of unsustainable bioenergy production,” said Melillo.
“As we approach the most important climate treaty negotiations in history, it is vital that technologies, such as biofuels, that are proposed as solutions to global warming, are properly evaluated,” said co-author Daniel Kammen, a University of California, Berkeley, professor of energy and resources and of public policy. “Our paper builds on recent work on the direct and indirect land use impacts of biofuels, and clarifies how the accounting should be done.”
CITATION: Melillo et al. Indirect Emissions from Biofuels: How Important? Science 22 October 2009.
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