Grain production is the key to feeding the growing human population. The yield of grain crops has been increasing since the advent of the agricultural revolution, and has made it possible to develop the urban culture of today supported by a diminishing number of farmers. In 1798 Thomas Malthus, a British Economist, first put forth the observation that population grows exponentially, while food production only grows arithmetically until it reaches some upper limit dictated by the amount of arable land. He concluded that if unrestrained by voluntary methods, the growth of population will eventually overtake the ability to produce food leading to starvation and war as a means of population control. Because of these predictions economics is still called the dismal science. Was Malthus correct?
Since 1800, when the world population was 900 million, the population has doubled every 70 years, slower than Malthus' assumption of doubling every 25 years. Food production has been able to keep pace because of several developments unforeseen by Malthus. Most significantly is the transfer of tremendous amounts of fossil fuel based energy into agricultural production. Pumping water from deep wells, or across mountain ranges to irrigate land that could not grow crops previously, has more than doubled the farmable acreage. Chemical fertilizers have increased yields and, together with the development of the tractor, made large scale farming practical. The internal combustion engine has also freed up large quantities of grain for human consumption that previously would have been allocated to feed draft animals. For centuries, farmers have been improving crop yields by saving seeds from the most productive plants, but in this century we learned the mechanism of inheritance which ushered in the Green Revolution, with a resultant increase in yields of rice and wheat worldwide by a factor of 2.5 since 1950. When all of the factors are taken into account, the 10 fold increase in food production in the last 200 years can be explained. Population growth is expected to add another 31/2 to 4 billion people before stabilizing. Can the planet support that many more people, and how will it be done?
If the chances of dramatically increasing yields per acre are limited, what about the supply land suitable for crops? Different countries have made attempts to increase grain production by bringing irrigation to arid lands. Most of the sites suitable for large scale irrigation projects have been utilized, and the river water is fully allocated. In fact over pumping of ground water may force millions of acres to be withdrawn from irrigation in the next 20 years. (see page on water resources) In 1970, Saudi Arabia began a massive experiment to become self sufficient in grain. They succeeded, but when the subsidies were withdrawn the production fell by 60%, leaving the country with greatly depleted water reserves and still dependent on imported grain. Other countries are cutting tropical rainforest in an effort to gain agricultural land, but there too, the benefits are marginal. Minerals rapidly leach from the soil in a very few years, leaving an impoverished, eroding landscape. The environmental impact of cutting the forest is huge, as it is valuable as a sink for carbon dioxide, a producer of oxygen, a moderator of temperature, and a habitat for countless species which are being driven to extinction. Climate models indicate that if enough forest is removed, the region will no longer produce the abundant rains, and further destruction will occur from drought and fire, negating any short term gain in farmland.
The total grain area harvested peaked in 1981, and declined by 8.7 % to 2000. The increase in soybean production has been dramatic during the same period as demand for meat has risen with the rising standard of living, but even when the area planted to soybeans is added in, there has been a decline of 5.2%. Some of this decline is reversible if grain prices rise, but some represents structural changes that may be irreversible, such as land lost to urbanization, or taken out of production due to lack of water.
Grain acreage per person from will decrease from .28A to .18A, or 35% from now to 2050 due to population increase alone. More severe demands will come in the rice growing areas. According to the International Rice Research Institute, 80-100 million additional people must be supplied with rice each year which will require a 70% increase in production over the next 30 years. Yields increased by 80% in the last 30 years, but, as mentioned above, it is unlikely that such gains can be duplicated in the next 30 years. In addition to the limitations of plant production and water, global warming will cause additional problems. An increase in the number an severity of droughts, heat waves and anomalous weather patterns will increase the need for water, and result in regional shortages and famines. The change in climate increases the odds of new plant pests and diseases disrupting production. In fact the IRRI has developed more than 300 varieties of rice in the last 30 years, many of them in response to new diseases. Grain growing area is also being reduced by the growth of urban centers as less developed nations enter the industrial age, and finally as these less developed countries gain in affluence, they will demand more meat which will require more grain for livestock feed. As grain becomes more scarce, and more expensive, there is a large built in reserve that can be tapped by reducing the level of meat consumption thus freeing up that grain for human consumption. While this is the logical solution, in an economic system that allocates resources to the highest bidder, the developing world will lack the financial resources to purchase enough grain from the wealthy nations to feed their rapidly growing population. Malthus predictions may come of age in this century.
With food production, there are two aspects to sustainability. First there is the issue of supplying enough food to meet the increasing demand. Secondly there are a host of environmental issues connected with high production agriculture. The first level of concern is with the continuing productivity of the farmland. Soil erosion, caused by farming hillsides, and poor farming techniques is responsible for tremendous losses of topsoil. Salt build up from irrigation water is an even more serious problem that has caused the decline of a number of cultures in the past. (Water) A second level of concern is the pollution caused by pesticides, fertilizers, and agricultural waste. A third issue is the potential health problems both in humans and animals from the widespread use of antibiotics in the raising livestock, poultry, fish, and fruit. Modern agriculture is totally dependent on the consumption of large quantities of fossil fuel used in fertilizer production, machinery, irrigation, and transportation. To produce one calorie of beef, uses 35 calories of fossil fuel*. By the time transportation, and manufacturing of the various inputs is included, estimates are as high a 500 calories of fossil fuel needed to put one calorie of food on the table. Modern agriculture is clearly on of the most unsustainable activities currently practiced because its ramifications are ubiquitous in the environment.