DURHAM, N.C. – An important but fixable error in legal accounting rules for bioenergy could undermine efforts to reduce greenhouse gases by encouraging deforestation, accounting to new analysis by 13 prominent scientists and land-use experts, including both the current and former deans of the Nicholas School of the Environment at Duke University.
The team of experts published its analysis as a “Policy Forum” article in the Oct. 23 issue of the journal Science.
In the article, the team explains that rules for applying the Kyoto Protocol and national cap and trade laws make a mistake by exempting the carbon dioxide emitted by bioenergy – energy derived from burning wood and other vegetation – regardless of its source. This legally makes bioenergy from any source, even that generated by clearing the world’s forests, a potentially cheap, yet false, way to reduce greenhouse gas emissions by foresters and farmers as well as oil companies, power plants and industry as they face tighter pollution limits.
According to a number of studies, including one by the U.S. Department of Energy, replicating this loophole in a global climate treaty could lead to the loss of most of the world’s natural forests as carbon caps tighten.
“The error is serious, but readily fixable,” says Timothy Searchinger, a research scholar at Princeton University and a fellow with the U.S. German Marshall Fund.
William L. Chameides, dean of the Nicholas School, notes that neither the Kyoto Protocol, which first contained the mistake, nor the European Union’s Emissions Trading System or the U.S. climate change bill passed by the House of Representatives this past summer, apply limits to emissions from land use. Because these laws nevertheless exempt all emissions from bioenergy use, they can unintentionally create large, perverse incentives to clear land.
“The solution, which we explain in our paper, is to count all carbon dioxide emissions from energy use, whether from fossil fuels or bioenergy,” says Chameides, “and then develop a system to credit bioenergy to the extent it uses biomass derived from ‘additional’ carbon sources, which offset energy emissions.”
The burning of bioenergy and fossil energy release comparable amounts of carbon dioxide from tailpipes or smokestacks, but bioenergy use may reduce emissions overall if the biomass results from additional plant growth, which absorbs carbon dioxide from the atmosphere and offsets the emissions from the eventual burning of the biomass for energy.
On the other hand, using carbon that would otherwise be stored in forests adds carbon to the atmosphere in the same way as using carbon otherwise stored underground in carbon or crude oil.
The Science article explains that the carbon accounting error stems from a misapplication of guidance by the Intergovernmental Panel on Climate Change (IPCC) at the time of the Kyoto Protocol. According to the IPCC, exempting carbon dioxide from bioenergy use is appropriate only if an accounting system also counts emissions from clearing land and other land-use activities.
This error in the system for administering carbon caps is distinct from other laws that require minimum quantities of biofuels. Many of these other laws, while imperfect, do attempt to account for at least some of the emissions from land use activities.
In addition to Searchinger and Chameides, the article’s authors are: Steven Hamburg of the Environmental Defense Fund; Jerry Melillo of the Woods Hole Oceanographic Institute’s Marine Biological Laboratory; Petr Havlik and Michael Obersteiner of the International Institute for Applied Systems Analysis; Daniel M. Kammen of the University of California at Berkeley; former Nicholas School dean William Schlesinger and Gene Likens, both of the Cary Institute for Ecosystems Studies; Ruben Lubowski and G. Philip Robertson of Michigan State University; Michael Oppenheimer of Princeton University; and G. David Tilman of the University of Minnesota.