Backlash against biofuels continues

The studies, published in Science, the magazine published by the American Association for the Advancement of Science (AAAS), look at the consequences in terms of emissions of the global conversion of large amounts of land to grow biofuels.

Land use
The first report, Use of US croplands for biofuels increases greenhouse gases through emissions from land-use change¹ (there is a clue in the title!), concludes that corn-based ethanol, the most popular biofuel in the US, instead of producing the widely quoted 20 per cent greenhouse gas emissions savings, actually nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. By the same measure, biofuels from switchgrass, if grown on land formerly used to grow corn, increase emissions by 50 per cent.

Proposals
The EU and a number of European countries have recently tried to address the land use issue with proposals stipulating that imported biofuels cannot come from land that was previously rainforest. But even with restrictions in place, the study says that the purchase of biofuels in Europe and the US leads indirectly to the destruction of natural habitats elsewhere.

It cites the example of vegetable oil prices rising due to increased demand for biofuel crops, which leads to more land being cleared as farmers in developing countries try to take advantage of the higher prices.

Second generation
The second report, Land clearing and the biofuel carbon debt², takes a more international outlook but its main finding is similarly gloomy. It says that converting rainforests, peatlands, savannas or grasslands to produce food crop-based biofuels in Brazil, Southeast Asia and the United States, creates a ‘biofuel carbon debt’ by releasing 17 to 420 times more CO2 than the annual greenhouse gas reductions that these biofuels would provide by displacing fossil fuels.

However, the second report also has a less widely publicised secondary conclusion, one which will come as no surprise to those who follow the biofuels sector a little more closely. It found that biofuels made from waste biomass or from biomass grown on degraded and abandoned agricultural lands incur little or no carbon debt and can offer immediate and sustained greenhouse gas advantages.

Gentlemen, welcome to second generation biofuels…

1 T. Searchinger, R. Heimlich, R.A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, S. Tokgoz, D. Hayes and T.-H. Yu, ‘Use of US Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change’, Science 319, (2008) 1238-1240.
2 J. Fargione, J. Hill, D. Tilman, S. Polasky and P. Hawthorne, ‘Land clearing and the biofuel carbon debt’, Science 319,(2008) 1235 – 1238.

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