sábado, febrero 09, 2008

The Un-Greening of Biofuels

Two new studies published online by the prestigious journal Science on Thursday raise serious questions about the green credentials of biofuels. The studies conclude that all or almost all biofuels in use today cause a net increase in greenhouse gas emissions, when scientists add in the environmental costs of their production.

In particular, the studies note, that the cultivation of crops for biofuels has in every case, directly and indirectly, caused the destruction of natural habitats, from rainforests to peat land, to savannahs. Those habitats are important global carbon sinks. When they are destroyed and plowed a huge amount of CO2 is released into the air that will be present for decades.

When you take such land use changes into account, “most of the biofuel that people are using or planning to use would probably increase greenhouse gas emissions substantially,” said Timothy Searchinger, a lead author on one of the papers.

Last year, the Dutch government stopped subsidizing the import of South East Asian palm oil — a green fuel that was used to generate “clean” electricity — after discovering that the palm oil was being harvested from new plantations created from drained peat land. (see article) Ouch.

The newly proposed European Union biofuels directive would forbid import of biofuels that are not produced sustainably, for example those grown on fields created from felled rainforest.

But the Science papers suggest such precautions are not enough to give them a good greenhouse gas profile, if the global effects are taken into account: Europe’s purchasing power has already driven up the price of vegetable oils (which can be used for either fuel or food). Lured by profits, farmers are already pulling acres of formerly pristine land into

The biofuels industry, fast growing and heavily subsidized, immediately condemned the studies. They say that biofuels are far cleaner than fossil fuels (though their calculation doesn’t include land use change).

The point is that the world really needs to figure out –quickly — what makes a fuel green — and what not. With just a few years to reverse emissions trends, it is important to support biofuels that will help the planet, and to reject the vast number that will merely spew more CO2 into the air.

By the end of the day, 10 of the most prominent environmental scientists in the U.S. sent a letter to President Bush urging him to re-think U.S. biofuel policy.