Agriculture is an energy-intensive industry, says Iowa State University Economist Don Hofstrand. In his September newsletter on renewable energy, he notes that farmers have been criticized because their use of commercial fertilizer and other technologies that enhance yields. But while that has been a dark cloud, there could be a silver lining.
Farmers are increasing their production of food to keep up with global population growth, which has grown from 3 billion in 1961 to 6.5 billion in 2005. Hofstrand calculated that crop output in that period rose from 1.8 to 4.8 billion tons. So food production went up 162% while population went up 111%, meaning more quantity and variety for everyone.
During that period Hofstrand said yield increased because of, “better crop genetics, improved mechanization and irrigation and increased use and effectiveness of pesticides and other chemicals. Although many of these factors lead to increased greenhouse gas emissions, they provide for the food needs of an expanding world population while not greatly expanding the world’s cropland area.”
Put that thought in reverse. If yields had not increased, there would be a greater need for more land to be cultivated, including some land that is best left in CRP, or in the case of global erodible land, never farmed at all. If more grassland had to be plowed and timber cut, then the greenhouse gas production would have substantially increased. Hofstrand looks at a Stanford University study that says in the last half of the 20th century yield per acre more than doubled. In that period the rate of fertilizer application increased 323%, while cropland increased 27%.
The researchers compared needed food production from intensive agriculture with fertilizer vs. extensive agriculture with a greater acreage under cultivation. To obtain enough land, 6.7 billion acres would be required or 20 times the U.S. area dedicated to corn and soybean production. If acreage were expanded greenhouse gas emissions rise 34%, but with stable acreage and improved technology, there is only an 18% increase in greenhouse gas emissions. Thus technology improvements have prevented the emission of 86.5 billion tons of greenhouse gas.
In the future, as global population rises to 37% by 2050, food demand will increase at twice the rate, and agriculture will need to be able to feed those people and also reduce greenhouse gas emissions. That will require more yield increases. So public and private research to increase yields will be necessary. Hofstrand says the additional goal should be to reduce the greenhouse gas emissions from the technology improvements.
The increasing global population demands more food and agriculture has to stay ahead with sufficient supply. However, the technology allowing that to happen has been emitting higher amounts of greenhouse gases. But without the increased technology, the only alternative to meeting the demand for food is to put more acres under cultivation. Doing so will emit more carbon dioxide than does the increased technology for yield increases.