Fourth Law of Thermodynamics With best intentions in 1958, Los Angeles County air pollution control regulators banned backyard garbage incinerators in the war against smog. After that particular pall lifted, the smog remained anyway. However, a new landfill industry was born in one of the fastest growing metropolitan areas in the nation. Soon the landfills contaminated groundwater, emitted toxic pollutants to the air, and created explosive hazards as the methane they produced underground infiltrated into nearby buildings. To eliminate the hazards--which took more than a decade to fully realize--environmental regulators had to require landfills be lined. The gases they produce underground were burned. This Catch-22 produced smog-forming air pollutants. Such is the history of the war on smog, replete with false starts, wrong turns, dead ends, and unintended consequences. The leaders who struggled with air pollution in the 1940s, 50s, and even the 60s were acting based on a limited understanding of a complicated problem. Despite their confident poses, in retrospect it\u2019s easy to see why the blue skies they repeatedly promised kept failing to materialize. Today, the situation is similar with global warming, a monumental problem not yet fully understood despite the common wisdom that the scientific debate is over. Leaders parade before the cameras in bravado to announce the solutions are at hand: cap-and-trade, emissions offsets, carbon sequestration, compact fluorescent light bulbs, and low carbon fuels. Following these and other easy steps will bring climate change under control like clockwork, many of them say. But the complications already are evident. How do regulators get a handle on greenhouse gas emissions from out-of-state power plants? That\u2019s a tough question. Tougher still is how to deal with the uncertainties in moving to \u201clow carbon\u201d biofuels, as ordered by the governor earlier this year to help achieve the greenhouse gas emissions reductions called for in the state\u2019s climate protection law, AB 32. Studies by Argonne National Laboratory, Tiax, and now the University of California, have brought the debate over the greenhouse gas reduction merits of food-based ethanol to a close in the minds of many. They have upended the critics who claim that corn mash actually increases greenhouse gas emissions on a net basis. End of story? Not quite. Corn acreage in California is up 78 percent over last year, an August 16 U.S. Department of Agriculture report shows. Meanwhile, acreage of cotton, rice, and alfalfa is down. The additional 125 square miles of corn, explains Dave Kranz, California Farm Bureau spokesperson, is not being grown to make ethanol, but largely to feed livestock in the state--California\u2019s \u201chappy cows.\u201d Another example is a plan to plant 234 square miles of sugar cane in the Imperial Valley, or about one-third the farmland there, to make ethanol. But these are just small examples of the changes afoot in the push toward ethanol to fill our gas tanks. Consider that the U.S. Department of Agriculture projects that by 2009, just halfway on the march toward the federally mandated sale of 7.5 billion gallons a year of ethanol in gasoline, the nation will convert 30 percent of its corn crop to ethanol. Now, even before making that mark, pending energy legislation in Congress would increase the ethanol mandate to 36 billion gallons a year. Tom Koehler, vice president of Pacific Ethanol, thinks maximum production of corn-based ethanol is 15 billion gallons a year. Raising the mandate effectively will eliminate U.S. corn exports from the world market, which now account for between 60 and 70 percent of the corn available for purchase on international markets. But it doesn\u2019t stop there. With the doubling of corn prices driven by increasing ethanol demand, acreage of the grain is up nationwide by 21 percent this year. Farmers planted 85.4 million acres in corn. A lot of the new acreage for the corn increasingly being turned into ethanol is being grown where farmers once raised less profitable soybeans, which also are a major export crop. Increasing the mandate will further displace other crops. Meanwhile, let\u2019s assume the U.S. Department of Agriculture is right that in two years 30 percent of corn acreage will be turned into ethanol, an area spanning 40,039 square miles, about the size of Kentucky. Where will the replacement for the suddenly lost food production come from to feed animals and a growing population in and outside the U.S.? Governments and people are unlikely to sit on their hands. The answer is that they will grow it themselves after clearing the land needed to do so. This, among other reasons, is why it still remains unclear whether today\u2019s corn-based ethanol really reduces greenhouse gas emissions. That\u2019s where we get back to the history of the rise of landfills following the ban on backyard incinerators. It probably will take ten years to fully realize the resulting problems, another ten years to develop solutions, and decades more to put them in place. Meanwhile, it behooves the state to do a better job of trying to answer these questions and track the perhaps unintended consequences of its biofuels gambit. For a start, California should not allow emissions trading credit for biofuels made from crops, since so little is really known about how the resulting land-use changes may alter things in other corners of the globe. And, if California is to live up to its size and ambitions in the climate change arena, another thing it must do is build the institutional capacity to adequately monitor and police any distant and unintended consequences from shifts in fuel use here. This will require the state to raise the money needed to staff up its environmental and energy agencies. After all, no matter how much you corn grow, or how many landfills you fill, there\u2019s no free lunch. Editors\u2019 note: For a more detailed version of the biofuels column, please see our sister publication E=MC2 \u2013 Energy Meets Climate Challenge. You can find it at www.energymeetsclimate.com.