Policymakers need to rethink the idea of promoting biofuels to protect the climate because the methods used to justify such policies are inherently flawed, according to a University of Michigan energy researcher.
In a new paper published online in the journal Climatic Change, John DeCicco takes on the widespread but scientifically simplistic perception that biofuels such as ethanol are inherently “carbon neutral,” meaning that the heat-trapping carbon dioxide gas emitted when the fuels are burned is fully balanced by the carbon dioxide uptake that occurs as the plants grow.
That view is misguided because the plants used to make biofuels — including corn, soybeans and sugarcane —already are pulling carbon dioxide out of the atmosphere through photosynthesis, said DeCicco, a research professor at the U-M Energy Institute and a professor of practice at the School of Natural Resources and Environment.
DeCicco’s paper is unique because it methodically deconstructs the life-cycle-analysis approach that forms a basis for current environmental policies promoting biofuels. Instead, he presents a rigorous carbon cycle analysis based on biogeochemical fundamentals to identify conditions under which biofuels might have a climatic benefit. These conditions are much more limited than has been presumed.
“Plants used to make biofuels do not remove any additional carbon dioxide just because they are used to make fuel as opposed to, say, corn flakes,” DeCicco said.
DeCicco stressed that research and development are important to create better options for the future. R&D is especially needed for bio-based or other technologies able to efficiently capture and use more carbon dioxide than is already being captured and stored by natural vegetation. But going beyond R&D and into subsidies, mandates and other programs to prop up biofuels is unwarranted, he said.
DeCicco’s direct carbon accounting examines carbon sources and sinks (storage sites, such as forests or crop fields) separately, an approach that lends greater clarity about options for addressing carbon dioxide emissions from liquid fuels.
“Biofuels have no benefit at the tailpipe,” DeCicco said.
