Much attention has recently been focused on the milestone of the world’s population reaching seven billion people. The milestone has raised concerns about the continued rapid increase in world population and the ability of world agriculture to feed the additional people. The answer to this question has important implications for renewable energy derived from biomass. The impact is not only the direct competition between corn for food and corn for ethanol, but also competition for farmland between food crops (e.g. wheat) and energy crops (e.g. switchgrass). Even if the energy feedstock is the by-product of a crop (e.g. corn stover) it may still impact food supply.
In this article I will examine the trends in world population growth, the track record of world agriculture in providing increased food production over recent decades and the potential for world agriculture to meet world food needs in the first half of the 21st century. Although of extreme importance to agriculture’s long-term ability to feed the world, I will not include the environmental issues and sustainability aspects.
Historic and projected world population milestones, along with the year in which these milestones were reached, are presented in Table 1. In the year Lewis and Clark embarked on their historic journey, world population reached one billion people. World population continued to increase but didn’t reach two billion until 1927, 123 years later. At this point, population started to grow rapidly reaching three billion people in 1960, only 33 years later. Four billion was reached only 14 years later. The rate of increase seems to have reached its peak at the turn of the century and began a slow decline in the rate of increase. It is projected that it will be 15 years before we reach eight billion and an additional 19 years before we reach nine billion.
Table 1. World Population Milestones (historic and projected)
Source: United States Census Bureau estimates
Population changes due to the relationship between births and deaths. If the number of births equals the number of deaths, population does not change. However, if births exceed deaths, the population grows. Historically, the world had a high birth rate but the population grew slowly because it also had a high death rate (e.g. high infant mortality). With improvements in world health and more people living through their reproductive years, population started to increase because the high level of births continued but the death rate dropped.
If this situation is maintained over a long period of time, population will grow exponentially. Essentially it is the same concept as compound interest for a savings account in a bank. The annual rate of increase is applied against a larger and larger base number. This has caused the explosion in population over the 20th Century.
This relationship between births and deaths is called the “fertility rate”. Essentially it is the number of children the average woman will give birth to in her lifetime. If the woman has two children, she will have replaced herself and her husband. If she has more than two, population will grow and if she has less than two, population will decline. To calculate the replacement fertility rate we must also take into account mortality from birth to reproductive age. The replacement fertility rate for industrialized countries is about 2.1 but higher for developing countries because their mortality rate is higher. The world average replacement fertility rate is estimated to be about 2.3 births per woman.
World fertility rates are shown in Figure 1. The fertility rate declined from 4.95 births per woman in 1950 to a projected 1.61 births per woman 100 years later in 2050. The current fertility rate is approaching the replacement fertility rate. However, population will continue to grow well into the future.
It may take several generations for a change in the fertility rate to be fully reflected in the rate of population growth. If the world has been in a period of high population growth, the number of young people of child bearing age will comprise a disproportionately large portion of the population. So population will continue to grow even if the fertility rate drops because the fertility rate will be applied to a disproportionately large number of people. Population will not stabilize until the age distributions within the population reach equilibrium. This is called the “population lag effect” or “population momentum”.
Figure 1. World Historical and Predicted Total Fertility Rates (1950 – 2100)
Source: United Nations, medium variant, 2010 revised.
The fertility rates by region are shown in Table 2 and vary greatly among regions. The fertility rate of Europe is well below the developed country replacement rate of 2.1. Populations in these countries are shrinking. This will cause a significant problem in these countries because the number of retired people is disproportionately large compared to the number of working individuals. This situation can be ameliorated through immigration from other countries. The opposite end of the spectrum is Africa where the fertility rate is well over the replacement rate and population growth is expected to continue into the future.
Table 2. Fertility Rates by Region of the World
Source: The Economist
The fertility rate also varies greatly among countries. Figure 2 shows the fertility rate of countries of the world. Most of the countries in Sub-Saharan Africa have very high fertility rates.
Figure 2. World Fertility Rates (2005 – 2010).
Agriculture’s Track Record in Feeding the World’s Population
World agriculture has been successful in keeping up with world population growth over the last half of the 20th Century. In fact, agriculture’s food production has increased faster than population during this time period. As shown in Figure 3, the value of food production has increased rapidly during this period, most of which occurred in the developing countries. The figure also shows the upward trend in the value of food production per person during this time period.
Figure 3. Total and Per Capita Agricultural Production
The increase by commodity varied greatly. As shown in Table 3, the top ten (by level of production) commodities in the world increased during the last 50 years. Wheat and rice more than doubled in production. Maize experienced a twofold increase and soybeans a fourfold increase. Cassava, an important commodity in developing countries, more than doubled during this time period. Vegetable production increased by 250 percent while potatoes experience just a modest increase.
Table 3. Increase in World Production of Top Ten Major Commodities
(1969 – 2009) (metric tons)
Although world agricultural production has increased faster than population growth, resulting in an increase in production per capita, the increases have not been distributed evenly across the globe. Production growth rates per capita for selected regions of the world are shown in Figure 4. The turquoise colored bars on the right of each grouping show the growth rate for the entire 1961 – 2004 period. East & South East Asia shows almost a 1.5% annual increase. However, Sub-Sahara Africa shows a decline in per capita agricultural production during this period. Average caloric intake per person per day for Sub-Saharan agriculture averaged about 2,100 calories while developing countries as a whole averaged about 2,650 calories per person.
Figure 4. Growth Rate in Total Agricultural Production Per Capita in Different Regions
Although the average situation in Sub-Saharan Africa showed a modest decline over the time period, the situation among African countries varied greatly. Of 26 Sub-Saharan African countries, 10 experienced food production declines from 1990 to 2004. The Democratic Republic of Congo declined the most with an average decline of 4.5 percent per year.
As shown in Figure 5, 37 out of 70 developing countries are considered food insecure countries. A food insecure country is a low income country where over 40 percent of the population is considered food insecure. Most food insecure countries are located in Sub-Saharan Africa, the same region that has the highest fertility rate as shown in Figure 2.
Can Agriculture Meet Future Food Needs?
World agriculture has met the food needs of an increased population and expanded world economy during the last half of the 20th Century, agriculture’s ability to meet the needs of an additional two billion people during the first half of the 21st Century is an open question. The Food and Agriculture Organization estimates that food production will need to increase by 70 percent by 2050. Below I will discuss ways of increasing agricultural production and some of the issues involved in these methods.
Increase Yields and/or Expand Cropland Area
The traditional approach to increasing world food production has been by expanding production area and increasing yields. The historic increase in world production of the three major commodities of wheat, corn and soybeans is show in Figure 6. Production increased from just over 400 million metric tons in 1960 to over 1,700 million metric tons in 2010. Almost all of the increase came as a result of yield increases. Cropland area expanded only modestly over the time period.
Figure 6. 2010 Global Production, Area & Yield (for Wheat, Soybeans and Corn)
Looking forward to 2050, the lion’s share of the production increase will need to continue to come from increasing yields. The ability to significantly increase farmland area is limited. In addition, the environmental damage and greenhouse gas emissions from expanding land area are great as discussed in AgMRC newsletter article, “Agricultural Research Combats Global Warming." So the focus will continue to be on increasing yields to meet world food demand. Concerns have been raised about the ability of the U.S. and other parts of the world to continue to increase yields due to reduced expenditures for research and technology, and rising input costs as more countries expand their use of fertilizer and other key inputs. Another major impediment is the impact that global warming and climate change will have on agriculture production levels as discussed in AgMRC newsletter article “Climate Change Beginning to Impact Global Crop Production.”
Historically, yield increases have not been consistent across the planet. Let’s use corn yields as an example. As shown in Figure 7, the U.S. has led the world in corn yield increases. This is followed by more modest increases in the European Union. After being stagnant during the 1960s and 1970s, the Middle East and South America have experienced significant yield gains. The former Soviet Union and Sub-Saharan Africa yields have lagged the rest of the world.
Yield gaps involve focusing on parts of the world where yields are not at the level they should be considering the current state of technology. Continuing the corn example, Figure 8 shows regions of the world where the yields gaps occur. Most noticeable are areas of Eastern Europe, Africa and Eastern Asia.
Source: Can We Feed the World and Sustain the Planet? Scientific American
Researchers at the Institute on the Environment at the University of Minnesota have estimated that closing the yield gap for the top 16 crops worldwide could produce 50 to 60 percent more food. This would involve raising crop yields of the world's most ineffective farms to 95 percent of the best yields attained by farmers in similar climates. (5) So another way of increasing production is by filling yield gaps.
A dimension of filling yield gaps and/or increasing yields overall is the additional crop production inputs needed to achieve these increases. Of special importance are the added fertilizer requirements and the demand on the world fertilize industry to source of these fertilizers.
Reduce/improve Meat Production
Increased food demand over the next forty years will come not only from the two billion person growth in world population but also from low income people in developing countries moving into the middle class. As people make this transition, they demand better diets. A large portion of this improvement is moving from direct consumption of grains to meat consumption. Because it takes multiple pounds of grain to produce a pound of meat, the amount of grain consumed increases as people make this transition.
Of the 70 percent total growth in food production needed by 2050, a portion of that will be , the World Bank estimates that it will need to increase by a quarter just to meet the needs of improved diets from people with rising incomes. So diet improvement is an important part of the equation for meeting future food demand. However, there may be a silver lining. The fertility rate tends to drop as incomes rise. Rising incomes across the globe may eventually slow or even stop population growth.
Changes in the consumption of animal products for both developing and developed countries are shown in Table 4. Although per capita consumption of both meat and milk has increased for both developing and developed countries over the 33 years, the increases among developing countries have occurred more rapidly. When combining the increase in per capita consumption with population growth, the increase in animal product consumption in the developing world is huge (e.g. meat consumption increased from 29 million metric tons to 143 million metric tons). Even with this large increase in animal product consumption, there is room for additional large increases in animal product consumption before the developing countries catch up with consumption in the developed countries (e.g. 48 kilograms per capita milk consumption to 202 kilograms per capita). Of course the future increase in animal products consumption in developing countries depends on their rate of economic growth.
Due to the increased demand for meat products in developing countries, the supply of meat production in these countries has also been expanding rapidly as shown in Figure 9. Poultry and pork production have expanded the most rapidly. These two meat sources are among the most efficient in converting grain into meat, although some types of sea food production may be even more efficient. However, the pounds of grain fed to animals still exceed the pounds of edible meat produced by the animals.
Figure 9. Meat Production in Developing Countries
The ability of the world to meet the increased food needs by 2050 could be improved if the world reduced its consumption of animal products. Reduced meat consumption would free-up large quantities of grain to be consumed directly. Dietary studies indicate that reduced meat consumption may lead to greater health in the developed countries. However, it is unlikely that per capita animal product consumption will decrease significantly in developed countries and meat consumption will continue to increase in developing countries. The way to impact the situation is to increase the efficiency of converting grain to animal products. The concepts of increasing yields and correcting yield gaps in grain production (discussed earlier) can be applied to animal product efficiency. However, this will require the world to make greater investments in research and outreach.
Reduce Food Waste
Generally it is assumed that all of the food that is produced is consumed. This is a faulty assumption. In the U.S. and other developed countries about 30 percent of the food is wasted at the point of consumption as discussed in AgMRC Article, “Domestic Perspectives on Food versus Fuel." To realize this you only need to think of buffets and other retail outlets of prepared foods to understand the level of waste. In the developing countries the waste occurs early in the supply chain due to failed crops, poor storage methods and problems transporting commodities. Efforts to reduce food waste in both developing and developed countries could make a substantial impact on our ability to feed nine billion people by 2050.
Although world agriculture has met the food demand of growing populations and expanding economies over the last half of the 20th Century, it faces a continued challenge to meet the continued growth in food demand over the last half of the 21st Century. In this article I have attempted to outline the issues involved and discuss ways of meeting this challenge. We must be diligent in meeting this challenge and make the necessary public and private investments of resources. We cannot simply assume that, although we met the food needs of the last 50 years, we will easily meet the food needs of the next 50 years.
The inclusion of renewable fuels from biomass sources further complicates the situation. In general, biofuels may have a difficult time competing with food demand from developed countries. Conversely, the food demand of developing countries may have a hard time competing with biofuels. This may be particularly evident for Sub-Saharan African populations that have low incomes, high population growth rates, stagnant economies and dwindling food production per person.
Rising incomes of people in developing countries allows them to compete for food more effectively, but it also increases overall world food demand making the competition between food and biofuels more intense. Rising incomes will also increase the demand for energy, which will in turn impact biofuels demand.
The corn ethanol industry has been criticized for moving corn from food to fuel uses. However, we must remember that even producing non-food energy crops (e.g. switchgrass) impact food production. Total cropland area is relatively fixed and increasing the acres of energy crops will displace acres of food crops. So the competition between food and fuel continues.
1 Wikipedia, World Population
2 Wikipedia, Total Fertility Rate
3 Electronic Journal of Sustainable Development, Population Growth, Increases in Agricultural Production and Trends in Food Prices. By Douglas Southgate – Professor of Agricultural Economics -- Ohio State University
4 Background Paper for the World Development Report 2008 -- Global Agriculture Performance: Past Trends and Future Prospects -- Mette Wik, Prabhu Pingali, and Sumiter Broca
5 Can we Feed the World and Sustain the Planet?, Jonathan Foley, Director of the Institute on the Environment, University of Minnesota, Scientific American, November 2011, pp. 60 – 65.
6 A Tale of Three Islands, The Economist, October 22, pp. 28 – 30.
7 Power point Slide Presentation, Curt Reynolds, USDA Foreign Agricultural Service (FAS), Office of Global Analysis (OGA), International Production Assessment Division (IPAD)