Wednesday, May 2, 2012
The end to cheap oil: a threat to food security and an incentive to reduce fossil fuels in agriculture
Fossil fuels are essential for modern, mechanized agricultural production systems. Petroleum products are used directly to power tractors, machinery and irrigation, and to transport, transform and package agricultural products. They are also used indirectly to manufacture fertilizers and pesticides and prepare seeds. Thus, food production is energy intensive. For example, approximately 2 000 litres per year in oil equivalents are required to supply food for each American, which accounts for about 19 per cent of the total energy used in the United States (Pimentel and others 2008).
As machines replaced farm workers, the energy output-to-input ratio declined (Figure 2) (Pfeiffer 2003). In industrialised countries today, one food calorie requires expending an average of between seven to ten calories of fossil energy (Dahlberg 2000).