Population pressures has made us intensify our agriculture and by doing that we have experienced significant soil losses. So we have a high level of population relative to output…Our problem is that we have no more new areas that we can colonize. And we have to stop land being lost. We estimate that our arable lands are diminishing each year by about 8000 hectares…We can produce enough food for 5 million people-but we have 7.3 million people… I am afraid that if the rate of population growth continues, we might have serious difficulties.
-James Gasana, Rwanda’s Minister of Agriculture, Livestock, and Forests 1991
The situation described by Gasana is not unique to Rwanda. The world’s population has been growing at unprecedented rates. The increasing population has put pressures on the existing global agriculture system to keep up with the growing number of people. The scramble to produce enough food has largely been successful in the last half century; between 1950 and 1990 the global production of food increased 2.6 fold, far greater than the population growth increase of 2.1 fold. Because of this increase, on average there is more food per person today then there was 40 years ago. Numerous farming technologies, as well as an increase in large-scale farms has allowed this increase, not just in the United States, but across the globe. However, a simple overview of success in agriculture is cause for false optimism. Evidence indicates that for environmental, social, political, and economic reasons, the growing population is putting unsustainable pressures on agricultural systems. As a result of this strain, the world will not be able to sustain a population of 10 billion people and steps need to be taken to avoid mass-starvation.
Globally, population is at record levels and continues to grow; the population of 5.3 billion in 1990 continues to grow at a rate of 1.8% a year. Despite the record gains in the production of food, it is estimated that more than 900 million people only get one meal a day. This number is expected to get worse. The rapid growth of the food supply has begun to slow over the past 50 years, and has lagged behind population growth in many areas. Some estimate that growth in food production will slow to 0.9% a year, a rate far lower than population growth. If no major changes are made, these predictions indicate that after twenty years, up to 890 million people, or 17% of today’s population, could die. This estimate is fairly conservative in that it does not factor in any climate changes.
These statistics paint a fairly bleak picture of the future of the food supply. Paul Ehrlich points out two main reasons current food production is not sustainable. For one, the modern technology and methods of farming used to boost production this far have been accompanied by large externalities. Irreversible environmental damage has already been caused. The second problem is that despite the food output today, the entire population is not fed. As many as a billion people are under-nourished. Most of the people who are hungry today cannot afford food. Thus, increases in food production are not helping; for example in parts of Africa and Latin America there has been an increase in starving people despite more food production. The remainder of this paper will look at these two problems in more detail.
Recent agricultural practices have taken an environmental toll. Every year, 95 million more people need to be fed with 24 billion less tons of topsoil and a trillion less gallons of water. This is a permanent loss on any time scale relevant to humanity. While agriculture is dependent on environmental variables, methods of mass-production used today are harming the system it is dependent on. There are few aspects of the environment that have not been exploited. However, there are a couple areas that have been directly effected, which will be explored here.
Soil erosion has been a major problem in agriculture. The primary cause has been over use, such as over-harvesting and over-plowing. Topsoil takes a relatively long time to replace; ecosystems generally replace a couple of centimeters per decade. The US government addressed the severity of the problem when it set aside 11% of cropland because of erosion. However, because of the long time scale of soil replacement, it can be expected that erosion will continue at an unsustainable rate.
The water supply presents a similar problem. There is a distinct limit to access to freshwater. New technology now uses even more water, which is has permanent effects on supply. As a result, aquifers are being used far above replacement levels. According to the USDA, somewhere between 6 inches and 4 feet of water beneath a fourth of US irrigated cropland is being used each year. The "green revolution", discussed later, only placed more demand on the already strained water systems.
A third environmental problem in sustaining the present growth in food supply is the depletion of the ozone layer. Air toxins can drastically reduce productivity of crop growth. During the 1980s, it is estimated that ozone depletion led to a 5-10% loss in crops. This is primarily because many crops are not used to the increase in UV-B exposure.
The problem of global warming is closely related to the depletion of the ozone layer. It too has detrimental effects on crops. Changes in climate and a rise in the sea level are two avenues in which agriculture is harmed. With a rise in the sea level, there is the obvious problem of the loss of any coastal farmland, as well as the constant threat of flooding. Secondly, aquifers in coastal areas could be contaminated with salt water, making them unusable sources of freshwater for farms. Global warming is only expected to increase, at present, the world is dependent on the burning of fossil fuels for 75% of its energy. Air pollution is only expected to increase with population growth. Models show that this could warm the earth at a rate 50 times faster than that of the past 10,000 years. This would strain agriculture growth because the constant need to adapt to a new climate. Equally drastic, models show that this trend could lead to a drying of the centers of northern climates, which would include the ever-important breadbasket.
These environmental effects and others are now being felt from the introduction of the green revolution. Started in the second half of the century, the green revolution was seen as the solution to the food problem. The increase in production was enormous, but so were the environmental effects. There are three major components to the green revolution: fertilizers, irrigation, and pesticides. In recent years, all three have started to show diminishing returns, which is part of why they will have a much smaller effect on production growth in decades to come.
The introduction of fertilizers between 1950-1990 resulted in a three-fold increased global grain production. However, this effect has long passed the point of diminishing returns in developed countries. Furthermore, the majority of farmers that can afford fertilizers are already using them. They also have the negative effect of polluting the surface and groundwater supply, a problem because both of these sources are being rapidly depleted.
In order to supplement water scarcities, irrigation became popular during the green revolution. Today 33% of crops produced comes from 17% of irrigated cropland. However, irrigation has environmental problems as well; land has lost some fertility as a result of being waterlogged and salinization. Irrigation is contributing to the overdrawing of aquifers at a rate of approximately 6.5 to 8 trillion gallons per year.
Pesticides, the third component to the green revolution, have faced their share of problems as well. Pesticide use never really made a large dent in the number of crops lost to insects and other pests. In recent years, many pests have become immune to these poisons, making them useless. These problems with green revolution technologies emphasize the fact that we have not found a sustainable mode of production. Though it is responsible for large amounts of growth in output, these technologies are not a permanent solution, especially in the face of future population growth.
Population itself is putting a lot of restrictions on agricultural growth. At this point, humans occupy or use almost 90% of non-desert land. About 17% of this is used for crops, the rest is used for urban or built land, pastures, and forests. There is little excess land for agriculture to expand on to. The current mode of production is not environmentally sustainable.
Unfortunately, but not surprisingly, other factors play a role in the growth of food production and people’s access to food. Logistical, social, and political forces are all contributing reasons that the world will not be able to feed a population of 10 billion. Many of these problems are concentrated in the Third World.
Because of globalization, the traditional geographic tie between location of crop failures and famine has been broken. Famine is now concentrated in developing countries. The areas that have the highest population growth rates are also the areas most adversely affected by food shortages. An estimated 1/5 of children in developing countries are malnourished, 10 million people have died of hunger or hunger-related diseases, and up to a billion people do not consume enough energy for daily activities. Because of the lack of adequate food, these countries are further handicapped by a less productive work force. This trend is not likely to reverse itself. One study found that providing sufficient food for the people who are now undernourished as well as additions in the population up to 10 billion would require a near tripling of food production by 2040. Mal-distribution contributes to this problem of isolated famines.
There is a global dependence on North America for many crops. This geographically concentration of dependence on one region is dangerous because it become very weather dependent. An example of this danger was illustrated in 1988 when a drought accompanied by record heat levels reduced US grain harvest by 27% and Canada’s harvest by 31%. In recent decades, over 100 countries have started to depend on the US and Canada to feed their populations.
Further food insecurity is partially caused by a dependence on various governments. In the past, governments have kept a buffer zone to prevent famine. Further precautions are made to ensure soil is not overused, and price supports have been used. However, support for some of these programs is in jeopardy, especially in the former Soviet Union and Eastern Europe. The loss of these subsidies will lower agricultural output. There are many more ways in which governments get involved in agriculture. Though for the most part it is helpful, increased globalization pressures are restricting many subsidies. This potentially could help the distribution of available food by making it more affordable in developing countries. It also could have the adverse effect of making farming too expensive to keep up with the growing population.
Agriculture systems are straining to keep up with population growth. Paul Ehrlich says that the human race is at a crossroads; "humanity is confronted with a serious dilemma: how it will balance the costs of inadequate levels of food production against the environmental costs of pushing closer to the biophysical limits to food production." It has become increasingly clear that the current method of agricultural production is environmentally unsustainable. The last half-century has seen the once rapid production growth rates begin to taper, while population growth is beginning to outpace it. Unless a major change is made, the world will not be able to feed a population of 10 billion.
1. Anne H. Ehrlich, "People and Food", Population and Environment, Vol 12, No. 3, Spring 1991, pp.221-229.
2. Paul R. Ehrlich et al. "Food Security, Population and Environment", Population and Development Review, Volume 19, Number 1, March 1993, pp. 1-32.
3. Lester Brown and Hal Kane, "Food Insecurity" in Full House, Reassessing the Earth's Population Carrying Capacity, W. W. Norton Company, New York, 1994, Ch 2, pp. 37-48.