University of Groningen

The use of agricultural resources for global food supplyIbarrola Rivas, Maria José

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Chapter 7. Identifying challenges for a sustainable future

127

Chapter 7.

Identifying challenges for a sustainable future of the

global food system

7.1 More food, more resources

In the past decades, the global food system has undergone fast changes. These

changes have been caused by population growth, urbanization, globalization of

the food system, increase of income levels, dietary changes, change in

production systems (green revolution), among others (Alexandratos &

Bruinisma, 2012). All of this has resulted in an increase of food demand which

has led to an increase demand for resources: mainly land, water and energy.

The increase of food demand and resources has been different among regions

due to different demographic, geographic and cultural situations. It is expected

that more resources will be required in the coming decades due to increase in

food demand which, again, will be different among regions. Many studies

address the need for a sustainable future of the global food system (Foley et al.,

2011; Godfray et al., 2010a, 2010b; Tilman et al., 2011).

The goal of this thesis was to analyse the sustainability of the global food

system. A sustainable food system should provide enough food for all people

with the lowest environmental impact. The assessment focuses on the impact of

food demand on the use of agricultural resources considering the dynamics and

regional diversity of population numbers, diets and agricultural systems.

Agricultural production requires a mixture of resources which are interrelated

(land, water, nutrients and labour). For instance, a strong trade-off exists

between nitrogen fertilizer and land, and between labour and machinery. The

lowest environmental impact of the food system has been assessed by

considering an efficient use and the major trade-offs of the agricultural

resources. Throughout chapters 2 to 6, the main trends of the last decades and

regional differences in the use of resources have been studied in detail. In this

last chapter, all the insights obtained throughout the thesis are integrated to

discuss the future sustainability of the global food system.

128

7.2 General methodology: integrative assessment as a

response to the existing literature

A rapidly growing line of research has emerged in the last decades studying the

urge for a sustainable future of the global food system. These studies can be

grouped into two main lines of research which have some limitations that

motivated the development of a new approach used in this thesis. The two lines

of research are described below.

The first line of research are global studies that assess the future use of

resources identifying challenges and sustainable solutions (Fresco, 2009;

Godfray et al., 2010a; Tilman et al., 2011). They discuss the future use of

resources based on average global trends, account for all main resources, and

discuss the impact of dietary changes (based on the nutrition transition theory)

and population growth (based on the demographic transition theory).

However, the global studies do not analyse the regional differences which could

strongly deviate from the global average. In some cases, considering the

regional differences may lead to different future projections for the use of

resources in comparison with the global projections, as this thesis has shown.

The second line of research are studies analysing in detail only one resource

accounting for regional differences: land (Fader et al., 2013; Kastner et al.,

2012; Ramankutty, 2008; White, 2007), nitrogen fertilizer (Bouwman et al.,

2009; Leach et al., 2012; Liu et al., 2010; Pierer et al., 2014; Shindo et al., 2006;

Xiong et al., 2008), water (Hoekstra & Mekonnen, 2012) or energy (Berners-Lee

et al., 2012; González et al., 2011). These studies quantify in more detail the use

of resources than the global studies, but do not consider the trade-offs with

other resources. By focusing in detail in only one resource, it is possible to miss

important consequences in the use of other resources. For instance, focusing in

reducing land use can result in large nitrogen fertilizer use to increase crop

yields. The trade-offs among resources have not been analysed in detail in the

existing literature.

The mentioned limitations of these two lines of research suggest the need for

an integrative assessment which considers both the regional differences

relevant for a global analysis and the trade-offs among the resources.

Throughout the thesis, the global differences in the use of resources were

studied in relation to the dynamics of population numbers, type of diets and

Chapter 7. Identifying challenges for a sustainable future

129

type of agricultural systems. These three factors are the main drivers for the

use of resources (see figure 7.1) and they differ throughout the world.

First, population numbers change differently among countries in relation to the

socioeconomic development of the population, education, urbanization and

others (demographic transitions: Chesnais (1992)).

Second, the daily diet of a person consists of several food products. The menu of

a person is different throughout the world in relation to the amount of calories

consumed as well as on the type of food consumed due to different income

level, food availability, food preferences, local traditions, urbanization, etc.

(Menzel & D’Aluisio, 2005). Taking cereals as example, a person in Turkey

might mainly consume wheat in contrast with a person that lives in Mexico

who mainly consume maize or a person in Bangladesh who mainly consumes

rice (FAO, 2013d). Also, some regions consume mainly traditional grains (fonio,

quinoa, sorghum) and others modern agricultural grains (hybrid maize) (Garí,

2001).

Third, every food product can be produced in a different production system

which differ in relation to the use of external inputs (organic VS inorganic

farming), the amount of these inputs (resulting in high or low crop yields), the

climate (in tropical regions three harvests a year are possible and in temperate

regions only one harvest), type of machinery (animal draft VS machinery), etc.

All these differences in production systems result in different productivities

and different use of resources per amount of food produced.

The aim to perform a global analysis accounting for all these global differences

and the trade-offs among resources results in a methodological challenge.

Therefore, simplification is necessary to come up with a global overview of the

main relations of these factors relevant for the global use of agricultural

resources.

In order to do this, a methodology was developed to analyse the major trends

and the global differences of the main drivers of agricultural resources and

their trade-offs. National data were used as examples to illustrate the global

spectrum of these differences. Because of this, the food security situation of

these countries is not calculated. Instead, the countries’ data were used to

understand the implications of changes in the drivers, to identify the regions

with the strongest challenges for achieving food security in the coming decades

130

and the origin of the challenge (increase of population, changes of diets,

availability of resources, other). The main two strategies of the methodology to

simplify the global food system are, first, identify the regional differences

relevant for a global analysis and for the use of resources and, second, analyse

the trade-offs among the use of resources.

The level of scale throughout the thesis is a combination of global and regional

scale. In order to compare global differences, it is necessary to always consider

the global scale and at the same time “zoom-in” in a regional scale to identify

the relevant differences for the global scale. The relevant regional differences

are identified with the following approaches:

Grouping the global population taking into account the size of the

group relevant for a global discussion. The grouping is based on the

relevant driver in relation to the use of resources (GDP, population

density or culture). For example, GDP per capita was used to discuss

the differences and changes in diets and population growth because

these two factors are driven by the differences in socioeconomic

development (chapter 2). Population density was used to discuss

differences and changes in production systems because crop yields are

related with the population density of the region (chapter 3). Finally,

culture (as geographical location) was used to discuss differences and

changes in diets because food preferences are related with culture

(chapter 6).

The production systems need to be simplified to identify relations

among the drivers and global differences. As a consequence, several

assumptions need to be done which allows to have a global overview of

the differences in production systems relevant for the use of

agricultural resources even though some details of the system are not

included. For instance, only one crop was used to represent one food

category. Wheat was used to represent cereals in order to identify the

impact of the different factors of crop production (crop yield, nitrogen

fertilizer used, productivity). Also, feed for livestock generally consist

of a mixture of crops but in this thesis it was assumed that one crop

was used as feed to identify the impact of the different production

factors of the feed (crop yield, inputs used, productivity, others) in the

use of resources.

Chapter 7. Identifying challenges for a sustainable future

131

The diets need to be simplified to identify regional differences and

their impact on the use of resources. In order to do this, the food

products were grouped into food categories relevant for the use of

resources. For example, all cereals (maize, wheat, rice, sorghum, millet)

were grouped as cereals because their production productivities

(resource use per amount of food) are similar among them. But, for

animal products a distinction needs to be done between the meat types

(beef, pork, chicken) because of the differences in resource use per

amount of meat produced.

Thus, an integrative analysis of the whole system has to follow the strategies

mentioned above. With this approach, less detail is considered but the results

show more relations and trade-offs which lead to discussions of the whole

global food system in relation to the use of resources. It is possible to identify

the regions or groups which will have the strongest challenges for food security

and the source of the challenge (population growth, resource availability,

dietary changes, etc).

The use of resources was studied with a demand perspective in order to

integrate all the different drivers of food demand in one analysis. In this way,

the starting point is what people demand to eat; and, then, trace back to the

agricultural production to assess the amount of resources that were needed for

the production of that demand of food.

The main drivers for the use of agricultural resources are population numbers,

type of diet and type of agricultural systems (see figure 7.1). The first two

determine the demand for food. The type of production system, in addition with

the food demand, determines the demand for resources. Other factors also

drive the use of resources indirectly such as socioeconomic development (GDP

per capita is used throughout the thesis as the indicator), population density

and culture. These three drivers determine the dynamics in population

numbers, diets and agricultural systems. Figure 7.1 illustrates the relations of

all these drivers to the demand of food and resources. These drivers are from

different disciplines so an interdisciplinary approach is needed.

132

Figure 7.1 Relations among the drivers of the demand for food and agricultural

resources. See text for details.

7.3 New insights from an integrative analysis

The insights obtained in each chapter of this thesis have led to identify the main

global relationships of the drivers shown in figure 7.1, their dynamics, the

regional differences regarding these drivers and the trade-offs among the use of

resources. Some of these findings deviate from existing literature and result in

different discussions for the future challenges of the global food system.

The potential for food production based on the availability of land, water and

nitrogen fertilizer was studied in chapters 2 to 4. These chapters analyse the

amount of food that is needed based on the number of people and/or the type

of diets, and the amount of resources that are needed and/or available to

produce it.

The availability of land and water is analysed in chapter 2. The inequality in

availability of land between the poor and the rich countries will strongly

increase by 2050 due to the large population growth of the poor countries. This

leads to discuss whether the available area will be enough for the food demand

of each region. The low availability of land in the poor regions indicates a need

for intensification of the production systems: increase the food production per

area. This is further studied in chapter 3.

Chapter 7. Identifying challenges for a sustainable future

133

The intensification of the production systems in relation to the availability of

land and the type of diet was studied in chapter 3. The intensification is

analysed based on the nitrogen application because of the strong relation

between nitrogen application and crop yields (Engels & Marschner, 1995). The

results show that the nitrogen application increases exponentially with the

reduction of land availability below an area of 0.1 ha of arable land per capita.

The type of diet has an effect on the intensification and parallels this relation.

Affluent diets with low population density show low nitrogen application, but

the same diet in highly populated areas shows a large nitrogen application.

These results deviate from existing projections of nitrogen fertilizer use. Tilman

et al. (2011) projects a global nitrogen fertilizer use in 2050 with a linear

increase following the trend of fertilizer use in the last decades. However,

chapter 2 has shown that two thirds of global population will live in countries

with less than 0.1 hectares of arable land per person. So, following the results of

chapter 3, the future use of nitrogen might be larger than the one predicted by

Tilman et al. (2011) because it might increase exponentially instead of

following the linear trend of the last decades.

A clear trade-off between land use and nitrogen fertilizer use is shown in

chapter 3 which is studied in detail in chapter 4. This trade-off is analysed with

a demand perspective by calculating the amount of both land and nitrogen

fertilizer needed per person. The results show the impact of different

production systems and diets on the use of both resources. In general, a

production system with large use of nitrogen per capita results in low land use

and vice versa. However, this trade-off is not linear, and some systems use large

amount of both land and nitrogen fertilizer. Also, a staple diet uses less land

and nitrogen fertilizer than an affluent diet. The nitrogen fertilizer use per

capita can increase a factor three from a staple to an affluent diet with the same

production system. For affluent diets with relative low use of land, only large

nitrogen fertilizer use is possible. The results in chapter 4 show the importance

to consider the trade-off between nitrogen fertilizer and land. This gives new

insights to the discussion of the land and nitrogen footprint studies in the

existing literature. The nitrogen footprint studies (Leach et al., 2012; Pierer et

al., 2014) suggest that a solution to reduce environmental impact caused by

nitrogen fertilizer is the reduction of its use. These studies do not account for

the strong trade-off with land. Chapter 4 have shown that in some cases, where

land is not largely available, the reduction in the use of nitrogen is not possible

even for very basic staple food diets. Similarly, the land studies (Kastner et al.,

134

2012; White, 2007) do not account for the use of nitrogen fertilizer. These

studies suggest that a desirable scenario is the reduction of land use. But, it is

necessary to consider the consequences of increase nitrogen fertilizer use (local

pollution, increase indirect energy use, affecting the global nitrogen cycle and

others) which these studies do not take into consideration.

In addition to production potential, the use of agricultural labour in relation to

diets and production systems is studied in chapter 5. The insights in this

chapter are useful to discuss the trade-off between labour and energy use

related with the use of machinery. Labour efficiency is 200 times higher in a

mechanized system compared with a non-mechanized system. This gain in

labour efficiency is possible with mechanization which replaces human labour.

In general, the degree of labour efficiency of the production system is related

with the socioeconomic development of the population. The labour efficiency is

reflected in the share of agricultural population in a country (Structural

transformation: Timmer (2009)). Low income countries have low labour

efficiency (large amount of hours of farm labour needed per kilogram of food

produced) by using non-mechanized systems (Pimentel & Pimentel, 2008).

With this system, one fulltime farmer produces the food for 5 people (chapter 5

of this thesis), which fits with the share of agricultural population in these

countries: around 30% of the population is engaged in agriculture (FAOc,

2013). In contrast, the share of agricultural population in high income countries

is less than 1 %. These countries have mechanized systems with high labour

efficiency in which one fulltime farmer produces the food for more than 100

people (chapter 5 of this thesis). The use of machinery indicates higher use of

fossil energy for fuel. The results of this chapter contribute to the studies of

energy use for food (González et al., 2011; Berners-Lee et al., 2012). These

studies indicate a need to decrease energy use per product to reduce

greenhouse gas emissions. However, due to the trade-off between machinery

and human labour, the reduction of machinery use might not be an option in

countries with a low share of agricultural population because not enough

labour force is available.

Thus, it is essential to consider the trade-offs among land, energy (fuel and

nitrogen fertilizer) and labour, to evaluate the sustainability of the global food

system. Sustainability is achieved with the lowest environmental impact of food

production. Since food production includes the use of all these agricultural

resources, the environmental impact should be evaluated considering the use of

all the resources at the same time.

Chapter 7. Identifying challenges for a sustainable future

135

The type of diet has an important impact on the use of resources as shown in

chapters 2-5. This general statement is not a novel finding and most of the

existing literature addressing the sustainability of the food system concludes

that dietary changes are the key for a sustainable future. For this reason, a

detailed analysis of the global differences in diets and their impact on the use of

resources is performed in chapter 6. The results show that regions change diets

following their own dietary composition and not a global or “western” pattern

as assumed by other studies (Pingali, 2007). This new insight has major

consequences for the use of resources in comparison with existing literature.

The regional dietary composition, especially of the animal food products,

results in different use of resources (with the same production system).

Regional changes to affluent diets will result in different use of resources. For

the same protein consumption, an affluent diet with the current food

preferences of a region in Central Africa needs 30% more land for the

production of animal products than the food preferences of North America.

Similarly, the food composition of animal products in China needs 30% less

land than the food composition in North America (figure 6.5). The assumption

of changing to a “western diet” implies following the dietary pattern of North

America or Western Europe. Chapter 6 shows that the diet in North America or

in Western Europe is not the food consumption pattern requiring larger

amount of resources. Food patterns with large consumption of beef such as the

average diet in Central Africa require larger amount of resources for an affluent

consumption. Thus, future changes to affluent diets could result in higher

amount of resources per capita than the ones in “western countries”.

All the new insights mentioned above can be combined to assess the future

challenges of the food system by 2050. By doing this, the discussion includes

relevant regional differences, the trade-offs and relationships among the

resources and drivers. So, results in an integrative assessment which is

described in the following section.

7.4 Feeding more than 9 billion people in 2050

Future demand for resources will differ among regions because of the

differences in socioeconomic, geographical and cultural situations. By taking

into account all the main drivers for the use of resources (income level,

population density, culture, population numbers, diets and agricultural

136

systems) and considering the trade-offs among the resources (land, water,

nitrogen, labour), an accumulation of challenges is identified for a certain group

of the global population.

Figure 7.2 Global population grouped based on their socioeconomic development to

discuss their expected changes in diets and population numbers, and then sub-grouped

based on their availability of land to discuss the potential of food production. See text for

details.

Chapter 7. Identifying challenges for a sustainable future

137

By 2050, 70% of the global population will live in countries with very low land

availability for food production (chapter 2 of this thesis). In this section, the

discussion of chapter 2 is integrated with food production possibilities in

relation to the type of diet and the need for a production system with high or

low crop yields (which was analysed in detail in chapters 3 and 4).

The global population is first grouped based on their GDP per capita in 2010

(World Bank, 2014) similar to chapter 2. Then, these groups are subdivided

based on their availability of arable land per capita. The values of arable land

are the numbers in 2010, see chapter 2 for the justification of this assumption.

The GDP per capita is the starting point because it is the indicator that impacts

all three drivers discussed through the thesis: population growth, dietary

changes, and agricultural production systems. By doing the grouping based on

income level, it is possible to identify the type of changes of food demand for

each group in the coming decades.

In 2010, the global population was around 7 billion people (figure 7.2). 2.6

billion people lived in countries where the average GDP per capita was lower

than US$1,000. This group is referred as the “low income group”. It includes the

countries of sub-Sahara Africa and also countries in Asia such as Bangladesh,

India, Pakistan and Vietnam (groups 1 and 2 of chapter 2). The second group

had an average income level between US$1,000 to US$10,000. This group is

referred as the “transition group”. It includes the countries in North Africa,

some countries in Asia such as China, Indonesia and the Philippines, most

countries in Eastern Europe and Latin America (groups 3,4 and 5 of chapter 2).

The third group had an average income level higher than US$10,000. This

group is referred as the “high income group”. It includes the countries in

Western Europe, some in Asia such as Japan and Korea, Australia, United States

and Canada, among others (group 6 of chapter 2). See Appendix 2 in chapter 2

for the complete list of counties in each group.

The major changes in population numbers are expected in the low income

group, the major changes in diets are expected in the transition group, and no

major changes in both population growth and diets are expected in the high

income group. So, the drivers of food demand are different among the groups.

The low income group will demand more food because of more people, the

transition group will demand affluent food because of dietary changes, and the

high income group will not demand more food. The share of each group in the

global population will be different in 2050 as a result to the different

138

population growth rates. The low income group will almost double and will

account to half of the global population (which only accounted to one third in

2010). In contrast, the high income group will not grow substantially. These

strong differences in population growth rates will increase the inequality in

land availability per capita as discussed in chapter 2.

The transition group is expected to have the largest changes to affluent

consumption due to the changes in socioeconomic development (Kearney,

2010). These countries will demand food for affluent diets. In contrast, not

large changes in diets are expected in the low income group, so these countries

will demand food for staple diets.

Following the discussion of chapter 2, the availability of land per capita is

analysed in more detail. The analysis includes both the need of intensification

of the production systems and the type of diet that will drive the demand for

food. Each group of figure 7.2 was subdivided based on the availability of arable

land per capita in 2050 (figure 7.2c). The requirement of land and nitrogen

fertilizer for a staple and affluent diets were used as the criterion for

production possibilities based on the insights obtained in chapter 4 (figure 4.2).

A staple diet needs 0.4 ha/cap with a low crop yield system with very low

nitrogen fertilizer use and needs only 0.08 ha/cap with a high crop yield system

with large nitrogen fertilizer use. In contrast, an affluent diet needs as much as

1.5 ha/cap in the low crop yield system and 0.3 ha/cap in the high crop yield

system.

The colours of figure 7.2c indicate the production possibilities in relation to the

per capita arable land availability for a certain diet (staple or affluent) , and a

certain production system (with high or low crop yields). The graph shows in

green the population that have enough land to produce an affluent diet with a

low crop yield system (more than 1.5 ha/cap are needed). In yellow, the

population that have enough land to produce a staple diet with a low crop yield

system (more than 0.4 ha/cap are needed). In orange, the population with

enough land for an affluent diet with a high crop yield system (more than 0.3

ha/cap are needed). In red, the population with enough land for a staple diet

with a high crop yield system (more than 0.08 ha/cap are needed). And in

black, the population with not enough land to produce the food with these

systems even for a very basic staple diet.

Chapter 7. Identifying challenges for a sustainable future

139

Chapter 3 showed that the global average availability of land in 2050 will be

0.15 ha/cap. The countries show strong variations which deviates from this

global average. With 0.15 ha/cap, more than enough land is available for a

person to have a staple diet produced with high crop yields (more than 0.08

ha/cap are needed). Though not an affluent diet since 0.3 ha/cap are needed.

However, by analysing production possibilities with the global average, the

strong land limitations of a large share of the population are not shown. Figure

7.2c shows that one fifth of the global population will not have enough land for

a basic staple diet with a high crop yield system (population in black). This

shows the need to analyse the land availability in more detail as it is illustrated

in figure 7.2c.

The low income group will demand food for a staple diet. More than one billion

people of this group will live in countries where less than 0.08 ha/cap of arable

land are available (share of population in black). This means that they will not

have enough arable land per person to produce a staple diet with the present

production systems. The rest of the group will have 0.08 ha/cap to 0.2 ha/cap,

which is enough to produce the food for a staple diet but with high crop yield

systems. In general, these countries currently have low crop yield systems. But,

they will have less than half the amount of land needed for a staple diet with

low crop yield systems. The low land availability indicates the urge for these

countries to increase crop yields. It is interesting to point out that none of these

countries will have enough land to produce an affluent diet even with high crop

yield systems.

The transition group will demand food for an affluent diet. In general, these

countries have a higher crop yield systems in comparison with the low income

group. Differently to the low income group, this group will have larger demand

for resources per person due to the changes to affluent diets. Figure 7.2c shows

that the majority of this group will have strong land limitations: more than 80%

of this group will live in countries where not enough land is available to

produce the food for an affluent diet with the present production systems (less

than 0.3 ha/cap available). 600 million people will not have enough land even

for a staple diet in high crop yield systems (less than 0.08 ha/cap available,

population in black), and 2500 million people will have enough land only for

staple diets with high crop yield systems (population in red). In the other hand,

600 million people will live in countries with more than 0.3 ha/cap (population

in orange and yellow), so enough land for producing the food for affluent diets.

These countries include Brazil, Russia, Thailand, Ukraine, among others.

140

The high income group will also have low availability of land but “only” for half

of their population (population in red and black). The rest will have large

availability of land: more than 0.3 ha/cap (population in orange and yellow).

With this amount of land, it is possible to produce the food for more than one

person with intensive systems. This means that they can feed more than their

own population. The type of diet can strongly influence the number of “extra”

people that can be feed with their available land. For example, the countries in

yellow, with a high crop yield system, can produce the food for 4-15 “extra

people” per inhabitant with staple diets or for 0.3-3 “extra people” per

inhabitant with affluent diets.

It is important to point out that in 2050 no country will have the land available

to produce an affluent diet with a low crop yield system and (almost) no

nitrogen fertilizer use: at least 1.5 ha/cap are needed. This value is 10 times

higher than the global average available land in 2050. This means that in 2050,

global population will be ten times higher than what the world could produce

with no nitrogen fertilizer for affluent diets. In other worlds, ten world would

be needed to produce the food for all people with affluent diets and no nitrogen

fertilizer.

To conclude, land availability will be unequally distributed between poor and

rich countries in the coming decades. The largest share of countries with large

land availability is in the rich group. And due to the low land availability of the

poor and transition countries, strong intensification is required for these

groups. This will result in an increase use of inputs to achieve high crop yields,

mainly nitrogen fertilizer. This can result in local pollution if management

practices are not efficient, and in an increase of indirect energy use to produce

the fertilizers.

In addition to the production possibilities (crop yields), the production systems

will change in relation to mechanization. The increase of socioeconomic

development of the transition group will result in a Structural Transformation

of their population (Timmer, 2009) in which the share of agricultural

population decreases. In these cases, mechanization needs to replace human

labour. So, large increase of energy use is expected for this group in relation to

fuel use for machinery in addition to the indirect energy use related with

nitrogen fertilizer use. The high income group already have highly mechanized

production systems, so changes in energy use are not expected for this group.

Chapter 7. Identifying challenges for a sustainable future

141

The production possibilities of figure 7.2 for the staple and affluent diet are

based on two examples of diets (figure 4.2). Chapter 6 showed that present

regional differences in dietary composition have a strong impact on the use of

resources. The land needed for an affluent diet in figure 7.2 is based on the

dietary composition of North America in 2010. But, the changes to affluent diets

of the transition group will follow different paths which will result in different

needs for land. Figure 6.5 shows that the land needed for the production of

animal products for an affluent diet is different in relation to the food

preferences of the region, even for the same protein consumption. For example,

an affluent diet with the meat and dairy preferences of a region in Africa can

use 30% more land than the meat and dairy preferences of North America. In

contrast, the meat and dairy preferences of China use 30% less land than the

preferences of North America. Therefore, figure 7.2 might look more optimistic

or pessimistic depending on the choice of food in the diet.

7.5 Looking for integrated sustainable solutions

The solutions for the strong challenges of the future food system mentioned

above and illustrated on figure 7.2 should fulfil food demand with the less

environmental impact as possible. So, a balance should be made between food

needed, resource use per capita and the trade-offs among resources.

The increase of crop yields for 80% of the population will be necessary to fulfil

food demand based on the low availability of land per person (black and red

shares of the population of low income and transition group in figure 7.2). In

general, the low income group have low crop yield systems due to the low use

of inputs resulting in depletion of their soil (Liu et al., 2010). These countries

should overcome the economic barriers to increase the use of inputs such as

fertilizers with efficient agricultural practices. Otherwise, they will not have

enough land to fulfil their food demand with low crop yield systems. Some of

the transition countries already use large amount of nitrogen fertilizer, for

instance countries in East Asia (Shindo et al., 2006; Xiong et al., 2008), though

the use is inefficient and causes large local pollution. Changes to efficient

practices can reduce environmental impact.

As mentioned before, the intensification of the production system for the

transition group will not only include the increase of crop yields (by increasing

the use of nitrogen fertilizer) but also the increase of machinery resulting in

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higher energy use. However, the increase of crop yields results in lower energy

use for machinery. As shown in chapter 5, the labour efficiency of a certain

amount of crop is related with the amount of hours of labour needed per

hectare and the crop yield obtained. By increasing the crop yield, the labour

productivity increases as well, so the amount of labour needed per kilogram of

crop produced is lower than with low crop yields. In the same way, the use of

machinery is more efficient and less fuel is needed per kilogram of food

produced. So, the increase in indirect energy use related with nitrogen fertilizer

(which increases crop yields) reduces the energy use for fuel.

Throughout the thesis, it has been shown the strong role of diets in the use of

resources. Therefore, the change in diets is a crucial sustainable solution. For

example, affluent diets result in large nitrogen application which can cause

local pollution (chapter 3), affluent diets require both more land and nitrogen

fertilizer use per person than staple diets (chapter 4), and affluent diets require

more labour per person than staple diets (chapter 5) which indirectly require

more fossil energy for machinery use per kilogram of food produced. So, the

change from an affluent to a staple diet can result in: a reduction of both direct

and indirect energy use, reduction of land use (which can increase biodiversity,

afforestation, etc), and a reduction in local pollution due to reduction of

nitrogen fertilizer use. However, the discussion should not finish but start in

this statement. It is essential not to generalize between a staple and an affluent

diet. Strong cultural differences in diets exist throughout the world which have

a relevant impact on the use of resources. It is necessary to do a distinction

among the animal food products, for instance the difference between a diet

with beef or pork consumption results in twice use of resources per capita for

the production of animal food products (chapter 6). Also, affluent vegetarian

diets with large dairy products consumption can result in larger use of

resources than an affluent diet with large consumption of pork or chicken

consumption (figure 6.5).

Thus, in order to come up with an integrative solution for the future of the

global food system, it is necessary to identify the source of food demand (more

people and/or change in diets) by analysing the drivers, and also consider the

availability of resources, the trade-offs among resources and the regional and

cultural differences.

Chapter 7. Identifying challenges for a sustainable future

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7.6 Recommendations for further research

The main achievement of this thesis was to develop an integrative assessment

by identifying the dynamics and regional differences of the main drivers of the

agricultural resources use and its trade-offs relevant for a global assessment.

This allowed to have a global overview of the food production challenges of

future food demand. This was possible by using available parameters of the

countries such as GDP per capita, population density, food supply, crop yields,

etc. The results pinpointed the specific region with the strongest challenges for

future food supply including the relevant drivers for the demand of resources.

The insights of this thesis should be used as starting point for further research

to analyse in detail the food challenges of each specific region and find local

solutions.

Figure 7.2c shows in black the countries with the strongest challenges for

future food security. Detail analysis for these countries should be done to

analyse future food production possibilities including local data which was not

included in this study: climate, soil conditions, specific management practices,

specific food preferences, etc. Then, the local food security situation of the

region can be discussed, and local solutions can be recommended.

Also, the methodology of this thesis was based on country level averages. In

some cases, strong differences within countries exist in socioeconomic

development, diets, and production systems, among others. Further research is

needed considering these differences in some countries and their impact on the

use of resources. A previous study (Ibarrola Rivas, 2010) has shown that the

use of land within the Mexican population is strongly different due to different

production systems among the states and diets among the poor and rich sector

of the population.

7.7 Final conclusion

To assess the future of the global food system, it is necessary to have a global

perspective and at the same time take into account the relevant regional

differences of socioeconomic development, population density, diets, culture

and availability of resources. This perspective allows having an integrative

understanding of the major factors driving the use of resources and results in

new insights for finding solutions. With this approach, this thesis has identified

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the following main points which summarize the strong challenges for the

future.

The increase of food demand in the coming decades will be in the low

and middle income countries. The present availability of land and

water is unequally distributed between the high and low income

countries. This inequality will increase due to the high population

growth in the low income countries. Because of this, the low and

middle income countries with high population density will have the

strongest challenges for achieving food supply with local food

production. Land and water are non-tradable resources, so their

availability limits the food production possibilities of the region. In

contrast, energy inputs (nitrogen and fuel) are tradable which can

increase the production possibilities by intensifying the production

system.

The low land availability in addition to the increase of economic

development will result in huge increase of energy use in agriculture

(nitrogen fertilizer and fuel). It is necessary to consider the trade-offs

between nitrogen fertilizer and land use, as well as human labour and

machinery use to discuss the implications of the changes in production

systems.

The type of diets will play an important role in the use of resources.

The regional dietary differences should be considered and not only

differences in socioeconomic development. The regional dietary paths

with low resource demand can be used as examples of potential

sustainable solutions for the future of the global food system.

In order to evaluate the sustainability of the food system, it is essential

to consider the use of all major agricultural resources at the same time.

Using energy use as a sustainable indicator for the food system, which

is commonly used in other systems, could have strong side effects due

to the trade-off between energy and land use. The reduction of energy

use for food production can increases the need for land. If land is not

available, food production could not be enough in relation to the

demand of the population. In this case, the food system is not

sustainable since it is not supplying enough food for all people.

Chapter 7. Identifying challenges for a sustainable future

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The different transitions of the drivers for food demand among regions

(population growth, dietary changes and changes in agricultural

systems) will end up in different demand for resources. The

sustainability of the food system in relation to the use of agricultural

resources will depend on the transitions of these drivers.

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