When you add together the natural gas in the fertilizer to the fossil fuels it takes to make the pesticides, drive the tractors, and harvest, dry, and transport the corn, you find that every bushel of industrial corn requires the equivalent of between a quarter and a third of a gallon of oil to grow it - or around fifty gallons of oil per acre of corn. (Some estimates are much higher.) Put another way, it takes more than a calorie of fossil fuel energy to produce a calorie of food. . . .Pollan calculates that growing and processing the McDonald's meal he and his wife and son ate one day for lunch (one burger and fries, two large sodas, one salad, one order of chicken McNuggets, and a large shake) consumed the equivalent of 1.3 gallons of oil.
It's not easy to calculate the energy cost of a burger and fries meal because the food-growing and processing system that brings it to your plate (or your car) is complicated. Futurist Jamais Cascio has made a reasonable attempt at figuring the carbon footprint of that meal, that is, its contribution to the rising levels of carbon dioxide and other greenhouse gases in the atmosphere. Producing a typical cheeseburger, he figures, adds ten pounds of carbon dioxide or its equivalent to the atmosphere. That doesn't sound like much, until you figure that Americans have a serious fast-food habit, averaging one to three burgers per week. For 300,000,000 of us, he says, even if you take the lower end of the range, our burger consumption makes the same contribution to global warming as 6.5 million Hummer H3 SUVs driven for a year!
My husband, Richard, and I like to cook, so we don't eat fast food. But after reading Pollan and Cascio, we're working on reducing the environmental cost of our meals by eating organic food, and eating as locally as possible. For dinner tonight, we had baked Yukon Gold potatoes straight from the farm in the San Luis Valley sixty miles away topped with basil pesto from our last summer's garden, a salad of mixed greens grown in geothermally-heated greenhouses just up the valley from us, and - okay, I admit it - Alaskan wild salmon. Not exactly local, but it was a special occasion. I have to admit though, the potatoes tasted at least as good as the salmon, perhaps because we bought them at the farm, and we know the soil and sunlight they grow from.