When fossil-fuel prices were low and we did not care much about pollution or emissions, we did not worry about the energy waste. Now that prices are higher and we care more about environmental impacts, we have to improve that 10:1 ratio. The inefficiency could get even worse in the U.S. as more people, powered by cheap air conditioning, move into areas where local food production can support a mere fraction of the growing population (think Phoenix). In these cases, even more energy is used either to bring inferior lands into production through energy-intensive fertilizers and irrigation or to move food from remote markets.
Global trends will aggravate the challenge. World population is projected to grow to more than nine billion by 2050. Per capita energy and food consumption will rise, too: notably, as people get richer, they consume more meat, which is much more energy-intensive than other foods. And climate change implies that food production will be hurt by crop losses from droughts and floods, saltwater intrusion into aquifers, higher temperatures (which will decrease the effectiveness of photosynthesis in many places) and competition from biofuels for farmland. As a consequence, experts predict that food production will have to double by 2050.
Local Farming Might Not Help
Unfortunately, thinking about some popular food production “solutions” through the lens of energy shows that they do not always help. For example, many people have latched onto the local-food movement, billing themselves “locavores,” as an antidote to the energy used to transport food long distances and the energy intensity of large-scale industrialized agriculture. “Eat local” campaigns encourage residents to shop for local food from farmer’s markets or nearby community-supported farms.
Spending our money in the local community rather than sending it far away can be economically valuable, and having a vibrant local-food system creates resiliency in the event of unexpected occurrences such as war or drought. Local farms, however, sometimes use marginal lands to produce nonnative crops that require more chemicals and more energy for irrigation, and they still get low yields. Strangely enough, shipping food thousands of miles can sometimes require less energy, emit less carbon dioxide and do less environmental damage.
For example, it is typically less energy-intensive to grow lamb in New Zealand, where the animals graze on rain-fed grass that grows mostly without fertilizer or irrigation, and ship it to the U.K. than it is to grow lamb in the U.K. using energy-intensive inputs. Further, large industrialized farms, outfitted with laser-leveled fields (to minimize water losses and fertilizer runoff) and GPS-equipped tractors (to optimize fuel use and crop density) and planted with genetically modified crops designed to use minimal water can be surprisingly resource-efficient when compared with a bunch of distributed farms that inefficiently use energy and water but are closer to home. A Stanford University study concluded that Big Agriculture has spared a lot of carbon emissions because of its yield improvements and economies of scale.
Vertical, urban farms or algae production for feed, now in prototype stages, also has the potential for even greater biomass production per square foot of land than local farms.
Some popular solutions for renewable energy actually complicate the food-energy system. Food-based feedstocks—corn, soy, sugar and palm—dominate the world markets for biofuels and create unhealthy competition for farmland and freshwater. In 2010 in the U.S., about 30 million acres—more than one fourth of overall corn production—were used to produce 12.7 billion gallons of ethanol. That share will rise significantly as the U.S. tries to meet the federal mandate that 20 percent of all liquid transportation fuel come from biofuels by 2022.