Can We Meet the World's Growing Demand for Food?
AgMRC Renewable Energy & Climate Change Newsletter
Professor Emeritus Agricultural Economics
Iowa State University
We have recently experienced years of variable crop yields and volatile commodity markets. This specter has raised the concern of our ability to feed the world’s growing demand for food in the long term. Food demand is expected to increase substantially by the middle of this century. Can we meet this growing demand? More specifically, can we meet this demand without putting enormous pressure on the world’s resources and causing environmental damage? I do not attempt to answer these questions in this article. Rather, I discuss several of the major factors driving the supply and demand for food over the coming decades.
Several issues impacting world demand and supply of food over the next 40 years are examined in this article. The primary demand factors are the world’s growing population and rising incomes in developing countries. Food supply factors of increasing yields, expanding agricultural area, closing yield gaps and increasing the productivity of crop and animal agriculture are discussed. Additional issues touched on are reducing food waste, improving international trade and reducing/eliminating world hunger. Climate change will also greatly impact future food supply and demand but will be addressed in future newsletters. Another factor that will be addressed in future newsletters is the impact of biofuels on future food supplies.
Food Demand Factors
The demand for food is expected to grow substantially by 2050. A major factor for this increase is world population growth. Demographic projections have a high degree of certainty, so projections of future world food needs based on population growth are quite reliable.
The other major factor contributing to this increase is rising incomes of individuals, especially those living in developing countries. Although increasing the incomes of millions of people in the world is a great benefit to those individuals, it does increase food needs and demands on the world’s agricultural resources.
Increasing people’s income is generated by world economic growth, However, long-term projections of future world economic growth are relatively uncertain. Basing expected food needs on projections of future world economic growth has considerable uncertainty.
The rate of population growth increased greatly from the 19th to the 20th Century. The year Lewis and Clark embarked on their historic journey in 1804, world population reached one billion people. World population continued to increase but didn’t reach two billion until 1927, 123 years later. At that point, population started to grow rapidly reaching three billion people in 1960, only 33 years later.
Historic and projected world population from 1965 to 2050 is presented in Figure 1. Four billion was reached in 1974 (14 years later), five billion in 1987 (13 years later) and six billion in 1999 (12 years later).
The rate of increase seems to have reached its peak at the turn of the century and has begun a slow decline. It is projected that an additional 15 years will be required before we reach eight billion and an additional 19 years (2046) before we reach nine billion.
Figure 1. World Population (1965 – 2050)
Source: Population Division of the Department of Economic and Social Affairs of the United
Nations Secretariat (2007) (1).
Population changes are 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 began to increase because the high level of births continued while the death rate dropped. This situation produced the exponential population explosion of the 20th Century.
The 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 a woman has two children, she will have replaced herself and her husband. If she has more than two, population will grow. 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 is 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.
The world’s fertility rate declined from almost 5 births per woman in 1950 to a projected 1.6 births per woman by 2050 (13). The current fertility rate is approaching the replacement fertility rate. The fertility rate and population for selected countries are shown in Table 1. Although China’s one-child policy results in a fertility rate well below replacement, other Asian countries like India and the Philippines are well above replacement. The fertility rate of many European countries is below the developed country replacement rate of 2.1. So, population in several of these countries is expected to decline over the next 40 years. The opposite end of the spectrum is countries in Africa such as Nigeria and the Democratic Republic of Congo where the fertility rate is well above the replacement rate and population growth is expected to continue into the future.
Table 1. Fertility Rate and Population for Selected Countries
|Democratic Republic of Congo
Source: The World Bank and International Food Policy Research Institute
Although the world’s fertility rate is approaching replacement, population will continue to grow well into the future. It may take several generations for this 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 though the fertility rate drops because the fertility rate will be applied to a disproportionately large share of the population. Population will not stabilize until the age distributions within the population reach equilibrium. This is called the “population lag effect” or “population momentum”. In addition to this effect, the population growth of individual countries may also be impacted by immigration/emigration policies.
In addition to population growth, food needs will rise due to the increasing incomes of people in developing countries as they move from low income into the middle class. As incomes increase, people tend to eat fewer grains and increase their consumption of meat and high value foods. This transition requires higher levels of resource use. It takes multiple pounds of grain to produce a pound of meat. So the total pounds of grain consumed per person, directly as grain and indirectly through meat, increases significantly.
Rising incomes are generated by growing world economies. Although projections of future economic growth are more tenuous than projections of population growth, there is general consensus that the world economy will expand in the long-term in spite of the current financial problems in the developed world.
Per capita consumption of meat and milk has increased in both developing and developed countries in recent decades. However, the increase among developing countries has occurred more rapidly. There is room for additional large increases in per capita animal product consumption in developing countries before it catches up to the developed countries.
Food Supply Factors
Now let’s turn to the issues on the supply side of the equation. The United Nations Food and Agricultural Organization (FAO) projects that food and feed production will need to increase by 70 percent by 2050 to meet the world’s food needs. However, predicting food needs and supplies decades into the future involves a lot of uncertainty and estimates can vary substantially.
Let’s look at the global track record over the last 40 years. World agriculture has generally been successful in keeping up with world population growth over the last portion of the 20th Century. But the increase has varied greatly by commodity. Table 2 shows the increase in the top ten commodities in the world (by physical production level) during the last 40 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 experienced just a modest increase.
Table 2. Increase in World Production of Top Ten Major Commodities (1969 – 2009) (million metric tons)
Source: U.N. Food and Agriculture Organization
Discussed below are some of the major factors involved in increasing supply. They are increasing yields, expanding cropland area, closing yield gaps and improving efficiency. Our ability to meet the world’s food needs of 2050 depend on our ability to drive these factors.
Increasing Yields and/or Expanding Cropland Area
Looking forward to 2050, the lion’s share of the production increase needs to come from increasing yields. If yield increases are not sufficient to meet demand, pressure will build to expand production area. Even if production area can be expanded sufficiently to meet demand, the environmental damage and greenhouse gas emissions from the expansion will be substantial.
Production area for staple crops has gone through periods of expansion and relative stability over the last 50 years. For seventeen years after the beginning of the green revolution, production area expanded at an annual rate of thirteen million acres per year, as shown in Table 3. Then land area rate of increase declined to a modest four million acres per year for the next twenty years. During this period, commodity prices were low. However, from the beginning of the new millennium until now, production area has been in a period of more rapid expansion of twenty four million acres per year. This corresponds to a period a strong world commodity prices.
Table 3. Recent Trends in Land Use for Crop Production (staple crops area) (1965 – 2011)
||Land Use Increase
||(mil. ac. / year)
|1965 - 1982
|1982 - 2002
|2002 - 2011
Source: Grassini, P. et al. Distinguishing between yield advances and yield plateaus in historical crop production trends. Nat. Commum. 4:2918 doi: 10.1038/ncomms3918 (2013). http://www.nature.com/ncomms/2013/131217/ncomms3918/full/ncomms3918.html
Over this 46 year period, the acreage of staple crops increased about 500 million acres or slightly over 20 percent. Of this increase about half was due to increases in rice, wheat and maize. During the rapid increase from 2002 to 2011, about 60 percent of the increase was due to rice, wheat and maize with another 25 percent from soybeans. Nearly all of this crop area expansion since 2002 has occurred in South America, Asia and Africa (2).
Crop yields are often projected into the future based on linear trends of the past. In other words, if the yield of a crop increased by two bushels per year in the past, then the two-bushel increase is projected into the future.
However, research at the University of Nebraska-Lincoln (2) shows a more complex assessment of past yields. Table 4 shows a summary of yield trends of three major crops in 36 countries and regions from 1965 to 2011. This area accounts for 70 percent of the world’s combined rice, wheat and maize production.
The research shows that yields of these three crops increased at an increasing rate in 12 percent of the world’s production area for these crops. Yields increased at a constant or linear rate for 27 percent of the world’s production.
Conversely, yields increased at a decreasing rate for 10 percent and actually reached a yield plateau in 31 percent of the world's production area. A yield plateau occurs when yield in an intense cropping system originally increased in a steady fashion but then stopping increasing and has since remained relatively constant. Geographic areas encountering yield plateaus include rice in eastern Asian and wheat in northwest Europe.
Table 4. Percentage of Global Crop Production under Different Crop Yield Trajectories
||Global Production *
||Increasing Rate **
||Upper Yield Plateaus
|Total Rice, Wheat & Maize
* Percentage of global production of rice, wheat and maize, and the three crops together accounted for by the 36 crop-country cases analysis in this study.
** The 36 crop-country cases were grouped according to the pattern of change in rates of crop yield gains during the 1965-2010 interval and total production was calculated for each group and for each crop.
Source: Grassini, P. et al. Distinguishing between yield advances and yield plateaus in historical crop production trends. Nat. Commum. 4:2918 doi: 10.1038/ncomms3918 (2013). http://www.nature.com/ncomms/2013/131217/ncomms3918/full/ncomms3918.html
This suggests that increasing food production through higher yields may not be as easy in the future as it has been in the past.
Closing Yield Gaps
Yield gaps occur where yields are not at the level they could be with full utilization of currently available agricultural production technology. Yield gaps are a result of not fully utilizing existing technology, thus differing from yield plateaus where the yield of a crop may have reached its biophysical limit.
Historically, yield increases have varied substantially across the planet. So, agriculture in many parts of the world has yield gaps. Let’s use maize yields as an example. Although the U.S. has used technology to improve corn yields, some parts of the world lag in their application of these technologies. Figure 2 shows regions of the world where maize yield gaps occur. Most noticeable are areas of Eastern Europe, Africa and Eastern Asia.
Figure 2. Yield Gap for World Maize Production
Source; Jonathan A. Foley, et al., “Solutions for a Cultivated Planet – Supplementary Information -- Figure S4a”, Nature 478, 337-342 (20 October, 2011). http://www.nature.com/nature/journal/v478/n7369/extref/nature10452-s1.pdf
Closing yield gaps offers great potential to increase crop production. A recent study estimated that increasing the yields of 16 important worldwide crops up to 95 percent of their potential could increase production by 58 percent. Bringing yields of these crops up to only 75 percent of their potential could increase production by 28 percent (3).
Improving Agricultural Productivity
Researchers at the Economic Research Service of USDA have examined changes in agricultural productivity (6). Essentially, productivity means developing new technologies that increase agricultural output per unit of agricultural input, or decrease the amount of agricultural inputs needed to produce a unit of agricultural output. For example, if the quantity of agricultural output increases by five percent and the quantity of agricultural inputs increases by two percent, then agricultural productivity increases by three percent, the different between the output increase and the input increase.
Total Factor Productivity (TFP) is defined as the amount of output per unit of total factors (production inputs) used to produce the output. Five factors or inputs were used in the USDA analysis -- land (acres), labor (hours), tractors (number), head of livestock (number) and amount of inorganic fertilizer applied. The analysis showed that global agricultural output grew by about 2.2 percent per year from 1961 to 2007, as shown in Figure 3. During this period, almost half of the growth in output was due to increased use of production inputs and the reminder was due to increased productivity. In other words, a substantial amount of the growth in agricultural output was due to the increase in the efficiency of production inputs in producing agricultural outputs.
Figure 3. Growth in Global Agricultural Total Factor Productivity, 1961-2007
An important ingredient in meeting the world’s food demand in 2050, while minimizing the impact on the world’s resources, will be maintaining or increasing the rate of agricultural productivity. High levels of productivity require significant investments in agricultural research and extension across the world. There is a long lag time from initiating research to the actual application of new technologies. So, these investments need to be made soon for the impact on productivity to fully emerge by 2050.
In addition to food demand and supply conditions, there are other factors that impact our ability to meet food needs in 2050. Factors discussed below include reducing food waste, improving international trade and addressing world hunger.
Reducing Food Waste
Generally it is assumed that all of the food that is produced is consumed. This is a faulty assumption. Estimates of the amount of food wasted vary but 30 percent appears to be a reasonable estimate. In low-income countries there is waste along the entire food chain but it is primarily in storing production after harvest. It is caused by poor post-harvest infrastructure and technology. Examples include losses from spillage, drying, contamination and consumption by pests.
Food waste in high-income countries is primarily at the point of consumption. Waste is prevalent at restaurants, buffets and other food service establishments. Food waste is also prevalent in the home.
The magnitude of the problem should not be underestimated. Assume we will need to increase agricultural production by 70 percent by 2050 to meet the food needs of nine billion people. Cutting food waste in half over the next forty years, which seems to be a reasonable goal, means we will only need to increase agricultural production by 45 percent instead of 70 percent. This is a much easier food production goal to reach and would reduce the negative impact on the world’s resources.
Higher food prices are a way to reduce waste. Much of the waste in high-income countries stems from the fact that food is cheap relative to the income levels of many consumers. However, higher food prices place a burden on consumer’s in low-income countries and low-income consumers living in high-income countries.
There are other ways waste can be reduced. Reducing consumer and food service waste in high-income countries should start with information campaigns to make people aware of the magnitude of food waste and ways in which food preparation and consumption habits and processes can be changed. A part of this awareness is to highlight the financial impact of reducing food waste. Also, new technologies can be implemented to better inform consumers of food quality and extend shelf life. It can be reduced in low-income countries by utilizing existing technologies to minimize waste from storage and transportation.
Improving International Trade
Countries with large areas of arable land relative to the size of their population tend to have the most food security. As shown in Table 5, the amount of arable land per person is highest in Oceania, North America and Europe. However, this is not where population will be increasing over the next forty years. North Americas’ population is expected to grow by only 4 percent and Europe’s population is expected to actually decrease by 1 percent (15). Half of the population growth is expected to occur in Sub-Saharan Africa where arable land per person is currently only three-quarters of an acre. Assuming arable land area does not change, the land area per capita will drop to half of an acre by 2050. Asia’s population is expected to grow by 41 percent with arable land currently only one-third of an acre. The larger population will decrease per capita land area to less than a quarter of an acre by 2050. So countries in these regions will need to either substantially increase their agricultural production (yields and/or land area) or import a larger portion of their food needs.
Table 5. Where people live vs. where food is grown
(acres per person) (2009)
||Arable Land per Person
|Middle East and North Africa
|Central America and Caribbean
Source: 2011 GAP Report, Global Harvest Initiative
Although FAO projects that developing countries will be able to meet most of their consumption growth by increasing domestic production, the world net imports of cereal grains are expected to increase by 2050.
It is not uncommon for countries to impose restrictions like export taxes or export embargoes on agricultural commodities sold to other countries. Restrictions become increasingly common when world shortages and high prices exist. These policies are meant to discourage exports and keep food within the country for domestic consumers. Essentially, the restriction means that our citizens eat first. If there is anything left over, your citizens can have some.
The long-term implications of export restrictions are negative to the world’s consumers and world agriculture. It distorts trade in agriculture commodities at the precise time when there should be no distortion. It greatly increases the vulnerability of poor countries that are net food importers. It penalizes long-term agricultural development and growth in exporting countries.
Currently there are over one billion chronically undernourished and malnourished people in the world. Seventy five percent of the poor in developing countries live in rural areas and are directly or indirectly tied to agriculture. Despite the large movement of world population from rural to urban predicted over the next 40 years (increase from 50 percent to 70 percent urban), population growth in rural areas is still expected to increase faster than employment opportunities.
FAO expects the number of undernourished and malnourished people to decline by 2050 but hunger will still exist for a large number of people. This will occur even if there are ample supplies of food in the world. Although notable exceptions exist, many hunger situations are not caused by an actual shortage of food. Rather, hunger is caused by the financial inability to buy food. About 20 percent of the world’s population lives on less than $1.25 per day. So this problem is more a sign of poor worldwide income distribution than a worldwide shortage of food.
The situation is exacerbated if there is a shock to the food system and commodity prices escalate. Volatile prices can lead to disruptions of international trade and have a significant impact on food distribution and prices, especially during periods of low reserves. Low-income food deficit countries need to reduce their vulnerability to international agricultural market shocks such as happened in 2008 when the price of commodities rose rapidly.
There are many moving parts in determining our ability to feed over nine billion people by 2050. We have examined many of them in this article (although there are additional factors we did not discuss). How these parts unfold will determine whether we are successful in meeting the needs of a growing population.
However, we are not helpless bystanders of this unfolding story. We have the ability to influence the outcome. We must be diligent in meeting this challenge and make the necessary public and private investments of resources. We can start by championing the worldwide funding of agricultural research and extension programs along with investments in agricultural production and infrastructure to increase productivity and close yield gaps. In addition we can strive to minimize international trade distortions, reduce food waste, improve rural education and job creation in developing countries and find ways to meet the food needs of the world’s chronically undernourished and malnourished population.
- How to Feed the World in 2050, Food and Agriculture Organization of the United Nations. Available online.
- Grassini, P. et al. Distinguishing between yield advances and yield plateaus in historical crop production trends. Nat. Commum. 4:2918 doi: 10.1038/ncomms3918 (2013).
- Foley, Jonathan A. et al., (2011) Solutions for a Cultivated Planet, Nature 478, 337-342 (20 October).
- Foley, Jonathan A., et al., (2011) Solutions for a Cultivated Planet – Supplementary Information, Nature 478, 337-342 (20 October).
- Foresight. The Future of Food and Farming (2011), Final Project Report, The Government Office for Science, London. Available online:
- Fuglie, Keith O. (2010), Accelerated Productivity Growth Offsets Decline in Resource Expansion in Global Agriculture, Amber Waves, (September), ERS, USDA, pp. 47-51
- Hofstrand, Don (2008) International Perspective on Food and Fuel, Renewable Energy and Climate Change Newsletter, Agricultural Marketing Resource Center, August
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- Trostle, Ronald, (2008) Global Agricultural Supply and Demand: Factors Contributing to the Recent Increase in Food Commodity Prices, Outlook Report No. WFS-0801, Economic Research Service, USDA, July, 30 pp.
- Wik, Mette, Prabhu Pingali, and Sumiter Broca, ”Background Paper for the World Development Report 2008 -- Global Agriculture Performance: Past Trends and Future Prospects”
- Wikipedia, World Population
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