The pluses and (mostly) minuses of biofuels

Cornfield waste, or stover; perennials grown on marginal land; or municipal waste, ranging from kitchen scraps to cardboard, could be used as feedstocks to produce ethanol using cellulosic technology. CHICAGO — Speakers at last week’s AAAS meeting presented abundant evidence that tropical rainforest destruction has accelerated in recent years, at least in part because of the worldwide push to produce more biofuels. As Europe and America rush to supplant polluting fossil fuels with plant-derived fuels like ethanol, soy and palm oil, farmers in the tropics are accelerating forest clearing to plant more sugarcane, soybeans and palm trees to meet the demand. What should be carbon-neutral biofuels – the carbon dioxide these plants take in while growing is returned to the atmosphere when they're burned, resulting in zero net carbon release – end up spewing more CO2 into the atmosphere as forests are slashed and burned. Carbon dioxide is such a potent greenhouse gas that one recent study estimated it will take hundreds of years to recoup the greenhouse gas damage of clearing rainforests to grow and harvest plants for biofuels. In one session, Michael Coe of Woods Hole Research Center in Massachusetts illustrated one ripple effect from the stampede to create more ethanol from corn in the United States. As corn prices skyrocketed several years ago, soybean fields were converted to corn, and the price of soy rose.