From his Cessna a mile above the southern Amazon, John Carter looks down on the destruction of the world’s greatest ecological jewel. He watches men converting rain forest into cattle pastures and soybean fields with bulldozers and chains. He sees fires wiping out such gigantic swaths of jungle that scientists now debate the “savannization” of the Amazon. Brazil just announced that deforestation is on track to double this year; Carter, a Texas cowboy with all the subtlety of a chainsaw, says it’s going to get worse fast. “It gives me goose bumps,” says Carter, who founded a nonprofit to promote sustainable ranching on the Amazon frontier. “It’s like witnessing a rape.” The Amazon was the chic eco-cause of the 1990s, revered as an incomparable storehouse of biodiversity. It’s been overshadowed lately by global warming, but the Amazon rain forest happens also to be an incomparable storehouse of carbon, the very carbon that heats up the planet when it’s released into the atmosphere. Brazil now ranks fourth in the world in carbon emissions, and most of its emissions come from deforestation. Carter is not a man who gets easily spooked–he led a reconnaissance unit in Desert Storm, and I watched him grab a small anaconda with his bare hands in Brazil–but he can sound downright panicky about the future of the forest. “You can’t protect it. There’s too much money to be made tearing it down,” he says. “Out here on the frontier, you really see the market at work.” This land rush is being accelerated by an unlikely source: biofuels. An explosion in demand for farm-grown fuels has raised global crop prices to record highs, which is spurring a dramatic expansion of Brazilian agriculture, which is invading the Amazon at an increasingly alarming rate. Propelled by mounting anxieties over soaring oil costs and climate change, biofuels have become the vanguard of the green-tech revolution, the trendy way for politicians and corporations to show they’re serious about finding alternative sources of energy and in the process slowing global warming. The U.S. quintupled its production of ethanol–ethyl alcohol, a fuel distilled from plant matter–in the past decade, and Washington has just mandated another fivefold increase in renewable fuels over the next decade. Europe has similarly aggressive biofuel mandates and subsidies, and Brazil’s filling stations no longer even offer plain gasoline. Worldwide investment in biofuels rose from $5 billion in 1995 to $38 billion in 2005 and is expected to top $100 billion by 2010, thanks to investors like Richard Branson and George Soros, GE and BP, Ford and Shell, Cargill and the Carlyle Group. Renewable fuels has become one of those motherhood-and-apple-pie catchphrases, as unobjectionable as the troops or the middle class. But several new studies show the biofuel boom is doing exactly the opposite of what its proponents intended: it’s dramatically accelerating global warming, imperiling the planet in the name of saving it. Corn ethanol, always environmentally suspect, turns out to be environmentally disastrous. Even cellulosic ethanol made from switchgrass, which has been promoted by eco-activists and eco-investors as well as by President Bush as the fuel of the future, looks less green than oil-derived gasoline. Meanwhile, by diverting grain and oilseed crops from dinner plates to fuel tanks, biofuels are jacking up world food prices and endangering the hungry. The grain it takes to fill an SUV tank with ethanol could feed a person for a year. Harvests are being plucked to fuel our cars instead of ourselves. The U.N.’s World Food Program says it needs $500 million in additional funding and supplies, calling the rising costs for food nothing less than a global emergency. Soaring corn prices have sparked tortilla riots in Mexico City, and skyrocketing flour prices have destabilized Pakistan, which wasn’t exactly tranquil when flour was affordable. 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. Why the Amazon Is on Fire This destructive biofuel dynamic is on vivid display in Brazil, where a Rhode Island–size chunk of the Amazon was deforested in the second half of 2007 and even more was degraded by fire. Some scientists believe fires are now altering the local microclimate and could eventually reduce the Amazon to a savanna or even a desert. “It’s approaching a tipping point,” says ecologist Daniel Nepstad of the Woods Hole Research Center.