A fixable error in the way carbon is counted in current U.S.
climate legislation and in the Kyoto Protocol could undermine efforts to reduce
greenhouse gas emissions by using biofuels, says a premier group of national
environmental and land use scientists.
"The promise of biofuels made from biomass is huge,
from both climate mitigation and economic perspectives," said Phil
Robertson, Michigan
State University
professor of crop and soil sciences and one of the authors of the paper
"Fixing a Critical Climate Accounting Error" published in the Oct. 23
issue of the journal Science. "But the promise could come up short if we
don't pay attention to the details. One of the most important details is how
the benefits of carbon capture are tallied. If we miscalculate the carbon
benefits, we may find out later that our policies and practices are
counterproductive; that they don't have the positive impact on climate that we
want them to have."
Robertson also is a member of the Great
Lakes Bioenergy Research Center,
a partnership between Michigan State and the University of Wisconsin-Madison
funded by the U.S. Department of Energy to conduct basic research aimed at
solving some of the most complex problems in converting natural materials to
energy.
The paper authors point out that the greenhouse gas
consequences of bioenergy can vary widely, depending on where the plants used
to produce the energy are grown. For example, fast-growing biofuel crops grown
on abandoned farmland can capture more carbon than existing plants and so
reduce greenhouse gas emissions. This is because the biofuel crop absorbs more
carbon from the atmosphere than would otherwise be stored. But if existing
forests are cut down and replaced with bioenergy crops, the carbon released
from the soil and mature trees, plus the loss of future carbon storage, is
greater than the carbon captured by the bioenergy crops.
Current carbon accounting measures mistakenly exempt all the
carbon dioxide emitted from bioenergy, regardless of the source. According to a
number of studies, including one by the U.S. Department of Energy, applying
current carbon accounting measures globally could lead to the loss of most of
the world's natural forests.
"The error is serious, but readily fixable," said
Tim Searchinger of Princeton
University and lead
author of the paper. "The solution is to count all the pollution that
comes out of tailpipes and smokestacks whether from coal and oil or bioenergy
and to credit bioenergy only to the extent it really does reduce greenhouse gas
emissions."
"To avoid environmental regret later and protect both
private and public investments, we need to get the carbon calculations correct
from the start," Robertson added. "Michigan is particularly well positioned to
benefit from correct carbon accounting practices. As the market grows for
cellulosic biofuels, Midwest producers will
benefit by growing biofuel crops on land not now being used for food
production. Correctly crediting our carbon from the start will help to ensure
the long-term market value for these fuels, protecting early investments by
farmers and refiners. Just like with financial audits, it's important for
carbon audits to be correct. We don't want to find out later that we've built
an industry on a false premise. Ultimately, we need to mitigate climate change
and we need practices in place that do so."
Original article
Michigan State
University's biofuel and bioenergy research