Oh, dear George W. Wasn’t biofuels from corn one of your great ideas? You may have to think again.

Using biofuels made from corn, sugar cane and soy could have a greater environmental impact than burning fossil fuels, according to experts. Although the fuels themselves emit fewer greenhouse gases, they all have higher costs in terms of biodiversity loss and destruction of farmland.

“Regardless of how effective sugar cane is for producing ethanol, its benefits quickly diminish if carbon-rich tropical forests are being razed to make the sugar cane fields, thereby causing vast greenhouse-gas emission increases,” Jörn Scharlemann and William Laurance, of the Smithsonian Tropical Research Institute in Panama, write in Science today.

“Such comparisons become even more lopsided if the full environmental benefits of tropical forests – for example, for biodiversity conservation, hydrological functioning, and soil protection – are included.”

In a study the scientists showed that that 21 fuels reduced greenhouse-gas emissions by more than 30% compared with gasoline when burned. But almost half of the biofuels, a total of 12, had greater total environmental impacts than fossil fuels. These included economically-significant fuels such as US corn ethanol, Brazilian sugar cane ethanol and soy diesel, and Malaysian palm-oil diesel.

Biofuels that fared best were those produced from waste products such as recycled cooking oil, as well as ethanol from grass or wood.

How you going to break that addiction now George?