university of groningen the use of agricultural resources for ......ibarrola rivas, m. j. (2015)....
TRANSCRIPT
University of Groningen
The use of agricultural resources for global food supplyIbarrola Rivas, Maria José
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.
Document VersionPublisher's PDF, also known as Version of record
Publication date:2015
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):Ibarrola Rivas, M. J. (2015). The use of agricultural resources for global food supply: Understanding itsdynamics and regional diversity. University of Groningen.
CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.
Download date: 25-08-2021
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
142
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
143
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
144
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
145
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.
146