Oil and food security linked

FROM FARM TO PLATE, the modern food system reties heavily on cheap oil. Threats to the oil supply also are threats to the food supply. As food undergoes more processing and travels farther, the system consumes ever more energy each year. The U.S. food system alone eats up as much energy as does all of France. The actual growing of food accounts for only one-fifth of this. The other four-fifths is used to move, process, package, sell, and store goods after they leave the farm. Some 28% of energy employed in agriculture goes to fertilizer manufacturing, seven percent to irrigation, and 34% is consumed as diesel and gasoline by farm vehicles used to plant, till, and harvest crops. The remainder is for pesticide production, grain drying, and facility operations.

The past half-century has witnessed a tripling in world grain production. About 2,029,000 tons were produced in 2004. While 80% of the increase is due to population growth and more demand, the remainder can be attributed to more people eating higher up the food chain, increasing per capita grain consumption by 24%. Higher demand primarily has been met by raising land productivity through higher-yielding crop varieties in conjunction with more oil-intensive mechanization, irrigation, and fertilization--not by expanding cropland.

World fertilizer use has increased dramatically since the 1950s. China now is the top consumer--rising beyond 40,000,000 tons in 2004. Fertilization has leveled off in the U.S., staying near 19,000,000 tons per year since 1984. India's reliance also has stabilized at around 16,000,000 tons per year since 1998. More energy-efficient fertilizer production technology and precision monitoring of soil nutrient needs have cut the amount of energy necessary to fertilize crops, but there remains room for improvement. As oil prices increase and the price of fertilizer rises, there will be a premium on closing the nutrient cycle and replacing synthetic fertilizer with organic waste.

The use of mechanical pumps to irrigate crops has allowed farms to prosper in the middle of the desert. It also has increased farm energy use, allowed larger water withdrawals, and contributed to aquifer depletion worldwide. As water tables drop, ever more powerful pumps must be employed, perpetuating and increasing the oil requirements for irrigation. More-efficient irrigation systems, such as low-pressure and drip irrigation, and precision soil moisture testing could reduce agricultural water and energy needs for many years to come. Yet, in many countries, government subsidies keep water artificially cheap and readily available.

Countering the historical trend toward more energy-intensive farm mechanization has been the adoption of conservation tillage methods--leaving crop residues on the ground to minimize wind and water erosion and soil moisture loss. Soil quality is improved through this technique, while farm fuel use and irrigation needs are lowered. Zero-till farming is practiced worldwide, especially in the U.S. and Brazil. Reduced tillage now is used on 41% of U.S. cropland.

Although agriculture is finding ways to use less energy, the amount consumed between the farm gate and the kitchen table continues to rise. While 21% of overall food system energy is used in agricultural production, another 14% goes to food transport, 16% to processing, seven percent to packaging, four percent to food retailing, seven percent to restaurants and caterers, and 32% to home refrigeration and preparation.

Food today travels farther than ever, with fruits and vegetables in Western industrial countries often logging thousands of miles from farm to store. Increasingly open world markets, combined with low fuel prices, allow the import of fresh produce year-round, regardless of season or location. However, as food travels farther, energy use soars. Trucking accounts for the majority of food transport, though it is nearly 10 times more energy-intensive than moving goods by rail or barge. Refrigerated jumbo jets--60 times more energy-intensive than sea transport--constitute a small but growing sector, helping supply Northern Hemisphere markets with fresh produce from places such as Chile, South Africa, and New Zealand.

Processed foods currently constitute three-fourths of total world sales. Frozen fruits and vegetables, for example, require energy for processing and packaging, as well as refrigeration during transport, at the store and in homes. Moreover, packaging canned fruit requires the high energy intensity of mining and manufacturing steel. Processing breakfast cereals necessitates five times as much energy as is contained in the cereal itself.

Most flesh produce and minimally processed grains, legumes, and sugars require very little packaging, particularly if bought in bulk. Processed foods, on the other hand, often are individually wrapped, bagged, boxed, or similarly overpackaged. This flashy packaging requires large amounts of energy and raw materials to produce, yet almost all of it ends up in landfills.

Food retail operations, such as supermarkets and restaurants, require massive amounts of energy for refrigeration and food preparation. The replacement of neighborhood shops by "superstores" means consumers must drive longer distances to buy their food and rely more heavily on refrigeration to store it between shopping trips. Due to their preference for large contracts and homogenous supply, most grocery chains are reluctant to buy from local or small farms. Instead, food is shipped from distant large-scale farms and distributors--again adding to transport, packaging, and refrigeration energy needs.

Fossil fuel reliance may prove to be the Achilles heel of the modern food system. Oil supply fluctuations and disruptions could send food prices soaring overnight. Competition and conflict could escalate quickly. Decoupling the food system from the oil industry is key to improving food security.

Danielle Murray is a staff researcher at Earth Policy Institute, Washington, D.C.

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