Biofuels Deemed a Greenhouse Threat
- Biofuels Deemed a Greenhouse Threat
By ELISABETH ROSENTHAL
Published: February 8, 2008
Almost all biofuels used today cause more greenhouse gas emissions than
conventional fuels if the full emissions costs of producing these "green"
fuels are taken into account, two studies being published Thursday have
The benefits of biofuels have come under increasing attack in recent months,
as scientists took a closer look at the global environmental cost of their
production. These latest studies, published in the prestigious journal
Science, are likely to add to the controversy.
These studies for the first time take a detailed, comprehensive look at the
emissions effects of the huge amount of natural land that is being converted
to cropland globally to support biofuels development.
The destruction of natural ecosystems - whether rain forest in the tropics
or grasslands in South America - not only releases greenhouse gases into the
atmosphere when they are burned and plowed, but also deprives the planet of
natural sponges to absorb carbon emissions. Cropland also absorbs far less
carbon than the rain forests or even scrubland that it replaces.
Together the two studies offer sweeping conclusions: It does not matter if
it is rain forest or scrubland that is cleared, the greenhouse gas
contribution is significant. More important, they discovered that, taken
globally, the production of almost all biofuels resulted, directly or
indirectly, intentionally or not, in new lands being cleared, either for
food or fuel.
"When you take this into account, most of the biofuel that people are using
or planning to use would probably increase greenhouse gasses substantially,"
said Timothy Searchinger, lead author of one of the studies and a researcher
in environment and economics at Princeton University. "Previously there's
been an accounting error: land use change has been left out of prior
These plant-based fuels were originally billed as better than fossil fuels
because the carbon released when they were burned was balanced by the carbon
absorbed when the plants grew. But even that equation proved overly
simplistic because the process of turning plants into fuels causes its own
emissions - for refining and transport, for example.
The clearance of grassland releases 93 times the amount of greenhouse gas
that would be saved by the fuel made annually on that land, said Joseph
Fargione, lead author of the second paper, and a scientist at the Nature
Conservancy. "So for the next 93 years you're making climate change worse,
just at the time when we need to be bringing down carbon emissions."
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