The biggest challenge in food security is to ensure enough production of food to feed the current and future population. There are many controversial points about what should be the best system to produce our food. For example, one of the most common arguments is that conventional production should be the future of our food production because organic production may require more land to feed the current population. In the next sections this argument will be addressed by trying to answer the question of how many people can be fed by organic and/or conventional agriculture.

            In order to answer this question is important to review the issue of population growth. The United Nations (2007) in their “World Population Report” estimated a population of approximately 6 billion (Figure 9). Within this population, 82% live in less developed countries and 18% live in more developed countries (UN 2007). In addition, the United Nations Report (2007) projects a population growth for 2050 equivalent to the actual population of China and India, meaning a global population of 9.2 billion people by 2050 (Figure 9). Consequently, by 2050 86% will live in less developed countries and 14% will live in more developed countries (UN 2007). As a result, global population growth will be the major driving force between food demand and food production.   

Figure 9. World population development (from UNEP/GRID-Arendal 2001)

            The relationship of population per agricultural land is a key factor to answer the question about the number of people that agriculture can feed. Nowadays, with a world population of 6 billion people, the mean value relationship of people per agricultural land in the world is about four persons per hectare, but this relation varies from 1.4 to 6.6 persons per hectare for North America and Asia respectively (See Figure 10 & Table 4) (UN 2007, FAOSTAT 2009). However, with an estimate of a world population of 9.2 billion by 2050 the mean value relationship of persons per crop land will increase to six persons per hectare, and for regions like Asia and North America the projections estimate relations of 9.4 and 1.9 persons per hectare respectively (See Figure 10 & Table 4) (UN 2007, FAOSTAT 2009). The limitation of natural resources is the principal problem of increasing the population density per agricultural land. For example, Figure 11 illustrates the amount of resources available for one person per year in USA and China, where it is a huge difference in terms of land, water, fuels, and forest products (Whitney & Rolfes 1993).  In the end, the growing pressure of population per crop land will increase the demand on natural resources making our ability to supply food demands more vulnerable.  

Figure 10. Population per crop land by year and region (UN 2007-2009, FAOSTAT 2009)

Table 4. Population per crop land for 2001 and a estimated for 2050 (UN 2009, FAOSTAT 2009)

Figure 11. Resource use in U.S.A. and China compared (from Whitney & Rolfes 1993)

            Now that the topics of population growth and population per crop land have been discussed, it is time to answer the question of how many people can be fed by agriculture. Table 5 shows the number of people who could be fed from different crops under conventional and agricultural systems. First, it is important to mention that the calculations in the Table 5 have a lot of limitations because in order to calculate the exact number of people that these systems can feed more data would be necessary to support these results. However, the raw numbers show in Table 5 will help us to get a general idea to answer our main question. In order to calculate the number of persons that could be fed, a mean production for each organic and conventional crop was estimated. Second, the kg/ha of production of each crop was transformed to energy in kcal per hectare. Finally, the total energy produced by each crop was divided by the mean energy required in the diet of one person (2600 kcal) and then divided by the number of days in one year. In the case of beef, the production was estimated for caws feeding from pastures, where one hectare can produce 2.5 animal units (AU) per year (AU=450 kg), with a beef performance of ~60% for each AU.

Table 5. Number of people that organic and conventional agriculture could feed per hectare and year.

^a (FAOSTAT 2009), (Pimentel 1993)

^b (FAOSTAT 2009), (Pimentel 1993)

^c (FAOSTAT 2009), (Miller & Ortega 2000)

^d (FAOSTAT 2009), (Pimentel 1993)

^e (FAOSTAT 2009), (Pimentel 1993)

^f (FAOSTAT 2009), (Miller & Ortega 2000)

^g Caws feeding from pastures

^h Whitney & Rolfes 1993

ⁱ 2600 Kcal/person/day (UN 2009)

The results of the analyses in Table 5 showed that organic and conventional systems of corn, potato, and soybean crops can feed our current and future population (see Tables 4&5). The conventional crops in Table 5 show higher values of productivity compared with the organic crops. However, as discussed previously, conventional systems require high levels of external inputs in order to maintain high productivity levels, making the system less efficient. Additionally, the problem with conventional systems is that we don’t know how long we can support the external inputs required to run this system (e.g. fossils fuels that are required to produce chemical fertilizers and pesticides). Ti would be perfect if conventional agriculture continued with this high productivity, but the big question is how long will natural resources maintain this system? Definitely, one alternative is organic production that despite its lower production still could supply the population food demands (see Tables 4&5). However, to feed our population with an organic system would require changes in our nutrition behavior and food distribution system. The next section will discussed in more depth why it is important to change our nutrition habits.