Biofuels may speed up, not slow global warming: study

CHICAGO, February 14, 2009 (AFP) – The use of crop-based biofuels could speed up rather than slow down global warming by fueling the destruction of rainforests, scientists warned Saturday.

Once heralded as the answer to oil, biofuels have become increasingly controversial because of their impact on food prices and the amount of energy it takes to produce them.

They could also be responsible for pumping far more carbon dioxide into the atmosphere than they could possibly save as a replacement for fossil fuels, according to a study released Saturday.

“If we run our cars on biofuels produced in the tropics, chances will be good that we are effectively burning rainforests in our gas tanks,” warned Holly Gibbs, of Stanford’s Woods Institute for the Environment.

Gibbs studied satellite photos of the tropics from 1980 to 2000 and found that half of new cropland came from intact rainforests and another 30 percent from disturbed forests.

“When trees are cut down to make room for new farmland, they are usually burned, sending their stored carbon to the atmosphere as carbon dioxide,” Gibbs said.

For high-yield crops like sugar cane it would take 40 to 120 years to pay