Scientists caution of bioenergy pollutants

By Lisa Gibson
Posted May 26, 2010, at 2:07 p.m. CST

Ninety American scientists are urging U.S. House and Senate leaders to accurately account for carbon dioxide emissions from bioenergy in any climate or energy legislation, saying the public perception that all biofuels and bioenergy are good for the environment is untrue. But Donna Harman, CEO of the American Forest and Paper Association, disagrees.

In a letter to U.S. House Speaker Nancy Pelosi, D-Calif., U.S. Senate Majority Leader Harry Reid, D-Nev., and other key Obama Administration officials, the scientists say ignoring the carbon impact of bioenergy can lead to increases in greenhouse gas emissions because not all forms of bioenergy produce less carbon dioxide pollution than fossil fuels.

The letter reads, "Clearing or cutting forests for energy, either to burn trees directly in power plants or to replace forests with bioenergy crops, has the net effect of releasing otherwise sequestered carbon into the atmosphere, just like the extraction and burning of fossil fuels. That creates a carbon debt, may reduce ongoing carbon uptake by the forest, and as a result may increase net greenhouse gas emissions for an extended time period and thereby undercut greenhouse gas reductions needed over the next several decades." Improper accounting of bioenergy could lead to large-scale clearing of the world's forests, it says. "Replacement of fossil fuels with bioenergy does not directly stop carbon dioxide emissions from tailpipes or smokestacks. Although fossil fuel emissions are reduced or eliminated, the combustion of biomass replaces fossil emissions with its own emissions (which may even be higher per unit of energy because of the lower energy to carbon ratio of biomass)."

Harman disagrees with the language of the letter, saying forest products facilities have used biomass as a renewable fuel and alternative to fossil fuels for two-thirds of their energy needs. "Emissions from the combustion of biomass historically have not been included in greenhouse gas reduction policies because biomass combustion does not increase carbon in the atmosphere when the overall biomass stock is renewed," she said. "When biomass is burned for energy, it releases carbon dioxide that was captured from the atmosphere back into the atmosphere. As trees are replanted, this carbon is reabsorbed, repeating the cycle. EPA's own data show that the biomass carbon cycle in the U.S. removes more carbon dioxide from the atmosphere than it emits."

The letter, complete with signatures, can be found at