Biofuels make greenhouse gases worse
Posted by ecoshift on February 10, 2008
Biofuels make greenhouse gases worse, scientists say | Seattle Times Newspaper
By ELISABETH ROSENTHAL
The New York Times
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 published Thursday have concluded.
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 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 that equation proved overly simplistic because the process of turning plants into fuels causes its own emissions — for refining and transport, for example.
These studies, published in the prestigious journal Science, 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, globally, the production of almost all biofuels resulted — directly or indirectly, intentionally or not — in new lands being cleared for food or fuel.