Biofuels do slightly reduce dependence on imported oil, and the ethanol boom has created rural jobs while enriching some farmers and agribusinesses. But the basic problem with most biofuels is amazingly simple, given that researchers have ignored it until now: using land to grow fuel leads to the destruction of forests, wetlands and grasslands that store enormous amounts of carbon.
Backed by billions in investment capital, this alarming phenomenon is replicating itself around the world. Indonesia has bulldozed and burned so much wilderness to grow palm oil trees for biodiesel that its ranking among the world's top carbon emitters has surged from 21st to third according to a report by Wetlands International. Malaysia is converting forests into palm oil farms so rapidly that it's running out of uncultivated land. But most of the damage created by biofuels will be less direct and less obvious. In Brazil, for instance, only a tiny portion of the Amazon is being torn down to grow the sugarcane that fuels most Brazilian cars. More deforestation results from a chain reaction so vast it's subtle: U.S. farmers are selling one-fifth of their corn to ethanol production, so U.S. soybean farmers are switching to corn, so Brazilian soybean farmers are expanding into cattle pastures, so Brazilian cattlemen are displaced to the Amazon. It's the remorseless economics of commodities markets. "The price of soybeans goes up," laments Sandro Menezes, a biologist with Conservation International in Brazil, "and the forest comes down."
Deforestation accounts for 20% of all current carbon emissions. So unless the world can eliminate emissions from all other sources--cars, power plants, factories, even flatulent cows--it needs to reduce deforestation or risk an environmental catastrophe. That means limiting the expansion of agriculture, a daunting task as the world's population keeps expanding. And saving forests is probably an impossibility so long as vast expanses of cropland are used to grow modest amounts of fuel. The biofuels boom, in short, is one that could haunt the planet for generations--and it's only getting started.
So what about those formulas that show that ethanol - particularly from switch grass or sugar cane - is "greener" than gasoline, even when you back out the fuel it takes to till the land and move the crops and everything else? Well, super-whammy, according this piece:
There was just one flaw in the calculation: the studies all credited fuel crops for sequestering carbon, but no one checked whether the crops would ultimately replace vegetation and soils that sucked up even more carbon. It was as if the science world assumed biofuels would be grown in parking lots. The deforestation of Indonesia has shown that's not the case. It turns out that the carbon lost when wilderness is razed overwhelms the gains from cleaner-burning fuels. A study by University of Minnesota ecologist David Tilman concluded that it will take more than 400 years of biodiesel use to "pay back" the carbon emitted by directly clearing peat lands to grow palm oil; clearing grasslands to grow corn for ethanol has a payback period of 93 years. The result is that biofuels increase demand for crops, which boosts prices, which drives agricultural expansion, which eats forests. Searchinger's study concluded that overall, corn ethanol has a payback period of about 167 years because of the deforestation it triggers.