Dwindling Fossil Fuels and Our Food System

Enlarge Image Image Gallery How much fuel did it take to produce the food on your table? PHOTO: ISTOCKPHOTO

Since 1981, the quantity of oil extracted from the earth has exceeded new oil discoveries by an ever-widening margin. In 2008, the world pumped 31 billion barrels of oil, but discovered fewer than 9 billion new barrels. World reserves of conventional oil are in a free fall, decreasing every year.

It can’t be denied: Agriculture uses a vast amount of oil. Most tractors use gasoline or diesel fuel. Irrigation pumps use diesel, natural gas or coal-fired electricity. Fertilizer production also is energy-intensive. Natural gas is used to synthesize the basic ammonia building block in nitrogen fertilizers. The mining, manufacture and international transport of phosphate and potash fertilizers all depend on oil. Our answer to the question of how we can end world hunger has thus far been to focus on increases in agricultural technology. These advances, unfortunately, require even more fuel.

Fertilizer production accounts for 20 percent of energy use on U.S. farms, and the demand for this fertilizer continues to climb. In addition, the international food trade separates producer from consumer by thousands of miles, further disrupting soil nutrient cycles. For example, the United States exports some 80 million tons of grain per year — grain that contains large quantities of basic plant nutrients: nitrogen, phosphorus and potassium. The ongoing export of these nutrients will slowly drain the inherent fertility from U.S. cropland if the nutrients are not replaced.

This international food trade is responsible for more than just soil nutrient depletion. Sustainable farming alone cannot solve this problem.The amount of energy used to transfer goods from farmer to consumer equals two-thirds of the total amount of energy used to grow it on the farm (see “U.S. Food System Energy Use” chart in the Image Gallery). An estimated 16 percent of food system energy is used to can, freeze and dry food — everything from canned peas to frozen orange juice from concentrate.

Food miles — the distance food travels from producer to consumer — have risen in the United States thanks to cheap oil. Fresh produce routinely travels long distances, such as from California to the East Coast. Most of this produce moves on refrigerated trucks.