Energy and the New Reality, Volume 1:
Energy Efficiency and the
Demand for Energy Services
Chapter 7: Agricultural and Food System Energy Use
L. D. Danny Harvey
harvey@geog.utoronto.ca
Publisher: Earthscan, UK
Homepage: www.earthscan.co.uk/?tabid=101807
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Energy Use in the Food System
•
•
•
•
•
Energy used in producing food
Energy used in transporting and processing food
Energy used to make packages for food
Energy used by food retailers
Energy used by consumers in getting, storing
and cooking food
Energy Used In Producing Food
• Energy to make fertilizers and pesticides
• Fuels for tractors and other equipment
• Fuels for heating and ventilation of farm
buildings, livestock and poultry facilities
• Electricity for irrigation (if used), lighting,
buildings
• Embodied energy in equipment and buildings
Figure 7.1 Energy used during the production of food
in the US
Electricity
21%
Fertilizers
28%
LP Gas
5%
Natural
Gas 4%
Pesticides
6%
Gasoline
9%
Diesel fuel
27%
Source: Schnepf (2004, Energy Use in Agriculture: Background and Issues, CRS Report for
Congress RL32677, www.nationalaglawcenter.org/assets/crs/RL32677.pdf)
Figure 7.2 Energy use in the US food system
Household
storage and
preparation
31%
Agricultural
production
21%
Transport
14%
Commercial
food services
7%
Retail food
services
Packaging
4%
7%
Processing
16%
Total non-solar energy input: 10.8 EJ/yr
Food energy produced:
1.48 EJ/yr
Nitrogen
• Occurs in the atmosphere as N2 (78% of air)
• Needs to be converted to NH4+ (ammonium) in
order to be useable (assimilable) by plants – a
process called nitrogen fixation
• Only certain bacteria, which live in the roots of
only certain plants, can carry out nitrogen
fixation
• Some ammonium is oxidized to nitrate (NO3-) in
a process call nitrification and taken up by plants
in that form
Figure 7.3 Nitrogen Cycle
N2O
N2
N2, N2O, NO
Fixation
Denitrification
NH4+
Nitrification
NO3-
Assimilation
Organic Matter
Mineralization
NO3NH4
Immobilization
Non-energy issues related to N fertilizer
• Leaching into groundwater and runoff into
streams and eventually the oceans
• Growing incidence of coastal oceanic dead
zones due to eutrophication
• Emissions of N2O (a powerful GHG) associated
with nitrification and denitrification reactions
• NO emissions, contributing to loss of
stratospheric O3
• NO and NO2 emissions (NOx), contributing to
buildup of tropospheric O3 and to acid rain
Distribution of eutrophication-assisted
coastal dead zones
Source: Diaz et al (2008, Science 321, pp926-929)
Distinction:
• Nitrogen fertilizer is manufactured, requiring
energy inputs and a source of H2, which is
combined with atmospheric N2 to produce NH4+
as a first step (both the energy and H2 come
from natural gas at most N-fertilizer plants,
although the Chinese use coal)
• Phosphorus fertilizer is mined from P-containing
rocks (phosphates)
Figure 7.4 Global P flow
Source: Cordell et al (2009a, Global Environmental Change 19, 292–305,
http://www.sciencedirect.com/science/journal/09593780)
Figure 7.5 Distribution of P reserves
Russia 1%
Other
9%
Brazil 1%
China
37%
Jordan 5%
US 7%
South Africa
8%
Morocco and
Western Sahara
32%
Non-energy issues with
respect to P fertilizer:
• Environmental impacts of mining, due to
contamination of most phosphate deposits with
toxic heavy metals (As, Hg, Pb, Cd)
• Inability to use most of the economicallyavailable phosphate (reserves) as fertilizer due
to heavy metal contamination
• Likely peaking of phosphate supply within 20-30
years even without toxicity constraints
Figure 7.6 Historical and projected annual P supply from mining,
the latter obtained using the logistic function combined with
estimates of the ultimate cumulative use
Phosphorus Mining (MtP/yr)
35
30
Actual
Modelled
25
20
15
10
5
0
1900
1950
2000
Year
Source: Cordell et al (2009a, Global Environmental Change 19, 292–305,
http://www.sciencedirect.com/science/journal/09593780)
2050
2100
Figure 7.7a World N Fertilizer Consumption
100
Consumption (Mt N)
90
80
70
non-OECD Countries
60
Former Soviet Union
50
OECD Countries
40
30
20
10
0
1970
1975
1980
1985
1990
Year
1995
2000
2005
Figure 7.7b World P Fertilizer Consumption
Consumption (Mt P2O5/yr)
40
35
30
non-OECD Countries
25
Former Soviet Union
20
OECD Countries
15
10
5
0
1970
1975
1980
1985
1990
Year
1995
2000
2005
Figure 7.7c World K Fertilizer Consumption
Consumption (Mt K2O/yr)
30
25
20
non-OECD Countries
Former Soviet Union
15
OECD Countries
10
5
0
1970
1975
1980
1985
1990
Year
1995
2000
2005
Figure 7.8a Worldwide N Fertilizer Consumption in 2001
Other
13%
Compound
(NPK)
11%
Ammonium
sulphate
3%
Urea
51%
Calcium
ammonium
phosphate
4%
Ammonia 4%
Ammonium
phosphate 6%
Ammonium
nitrate
8%
Total = 82.4 million tonnes N
Figure 7.8b Worldwide P Fertilizer Consumption in 2001
Triple
superphosphate
6%
Potassium
phosphate
1%
Single
superphosphate
20%
Ammonium
phosphate
45%
Compound (NPK)
28%
Total = 31.9 million tonnes P2O5
Figure 7.8c Worldwide K Fertilizer Consumption in 2001
Potassium
phosphate
2%
Compound
(NPK)
31%
Potassium
chloride
67%
Total = 22.2 million tonnes K2O
Figure 7.9 Worldwide Fertilizer Energy Use in 2001
Mixed
16%
Potassium
2%
Phosphate
10%
Nitrogen
72%
Total = 3.66 EJ
Strategies to reduce the amount of
energy used in making fertilizers
• Increase the efficiency in manufacturing
fertilizers
• Reduce the demand for chemical fertilizers
Strategies to reduce the demand for
chemical fertilizers
• Use any applied chemical fertilizers more
effectively, so that less is needed
• Substitute organic (natural) fertilizers for
inorganic (manufactured) fertilizers
Figure 7.10 Fertilizer embodied energy
1960
2000
200
150
100
50
Nitrogen
Phosphorous
Mixed
Potash
NPK-1
NPK-2
SSP
TSP
AP
PK 22-22
Ammonia
Urea
AN
0
CAN
Energy Intensity (GJ/tonne)
250
Ways to reduce waste and runoff of
inorganic fertilizers:
• Apply only what is needed based on updated
measurements of soil conditions
• Apply fertilizers 2-3 times per year rather than 1
large application per year (sometimes in the fall!)
• Apply fertilizer in rows during seeding rather
than over the entire field (10-30% savings)
• Maintain fertilizer application equipment (20%
savings)
Overall estimated savings potential in
The Netherlands: 35-40%
From Table 7.4, percentage of added N
fertilizer that is absorbed by plants, as
measured on farms
• For corn in the north central US: 37%
• For rice in Asia when no guidance is given to
farmers: 31%
• For rice in Asia when fertilizer application is
adjusted to match needs: 40%
• Wheat in India, poor year: 18%
• Wheat in India, good year: 49%
Figure 7.11 US corn yield and fertilizer use
10
30
9
25
Nitrogen
Yield (tonnes/ha)
7
20
6
5
15
Potash
4
10
Phosphorus
3
2
5
1
0
1970
1975
1980
1985
1990
Year
1995
2000
0
2005
Fertilization Rate (kg/t)
8
Yield
Organic fertilizers:
•
•
•
•
Manure
Crop residues
Food processing wastes
Human wastes
Issues related to use of
organic fertilizers:
• Proximity to fields (especially with large
centralized feedlot operations)
• Bulk
• Contaminants (an issue with municipal sewage
plant sludge)
• Controlled release of nutrients
Pesticide use and energy intensity
Table 7.5 Worldwide and US pesticide use during 1998-1999, and
energy intensities.
P esticid e
H erb icid es
In secti cid es
F u n gicid es
O th er
Total or m ean
P esticid e U se
(m illion k g A I /yr)
W orld
US
948
246
643
52
251
37
721
219
2563
554
E n ergy
In ten sity
(M J/k gA I)
80 -450
70 -580
60 -400
280
280
E n ergy U se
(E J/yr)
W orld
US
0.251
0.065
0.209
0.017
0.058
0.009
0.203
0.06 2
0.721
0.15 2
Sources: Pretty (2005, in Issues in Environmental Science and Technology, No 21, Sustainability in
Agriculture, Royal Society of Chemistry, London ) for use and
Helser (2006, in Encylcopedia of Pest Management, Taylor & Francis, London ) for intensities.
A number of jurisdictions in the world have set aggressive
targets for reducing pesticide use, or are experimenting with
systems involving much lower use of pesticides.
• 50% reduction targets for the Canadian provinces of
Ontario and Quebec
• Integrated Pest Management (IPM) projects have been
carried out around the world
• A survey of 62 IPM projects from 26 countries found that
crop yield increased when pesticide use was decreased
in 60% of the cases
• This could be related to an overall improvement in
management practice associated with the training that
farmers received as part of IPM, or due to money saved
on pesticides being invested in other ways to increase
yields
Low-input farming systems
• No-till agriculture
• Organic agriculture
• Urban agriculture
No-till agriculture
• Avoids tilling (overturning) the soil
• Saves fuel, conserves soil moisture and reduces
wind erosion
• Usually is accompanied by increased use of
herbicides (tilling removes weeds – this is no
longer done) and sometimes by increased use
of fertilizers
• Net result: very little change in energy use
Table 7.7 Comparison of energy inputs for conventional and organic
farming in Finland. Required land areas are given as hectares per
functional units (FUs) of either 1000 kg bread or 1000 litres milk.
Pre-farm total
Electricity
Purchased fodder
Fertilizer
On-farm total
Electricity
Fuels
Pre- and on-farm total
Post-farm total
Bakery or dairy electricity
Bakery or dairy fuels
Packaging
Transportation of inputs and
outputs up to the point of retail
sale
Grand Total
Land area required (ha/FU):
Rye
Conventional
Organic
2.38
0.10
0.40
0.07
1.98
1.26
0.08
1.18
3.64
11.02
6.76
3.81
0.45
0.67
0.03
1.51
0.08
1.43
1.61
11.02
6.76
3.81
0.45
0.71
15.33
0.188
13.34
0.319
Milk
Conventional
Organic
3.02
0.81
0.09
0.05
0.19
0.13
2.74
0.63
1.12
1.33
0.74
0.73
0.39
0.59
4.14
2.14
1.99
1.99
0.59
0.59
0.40
0.40
1.00
1.00
0.25
0.29
6.39
0.240
4.41
0.434
Source: Grönroos et al (2006, Agriculture, Ecosystems and Environment 117, 109–118)
Table 7.8 Comparison of energy inputs (GJ/ha/yr) for conventional and
organic systems of farming for two case studies in Denmark.
Spring Barley on Irrigated Sandy Soil
Conventional
Organic
Milk
Conventional
Organic
Direct energy use
Fuel
Lubricants
Irrigation
Drying
Subtotal
3.4
0.3
1.5
0.5
5.7
5.0
0.4
1.5
0.4
7.3
Indirect energy use
Machinery
Fertilizers & Lime
Pesticides
Subtotal
1.1
6.7
0.3
8.1
1.6
0.1
0.0
1.7
Total Energy Use
Yield (kg/ha)
Energy Use (MJ/kg)
13.8
5000
2.8
9.0
3600
2.5
Grazing fodder
Grass silage
Whole crop silage
Grain cereals
Concentrates
Straw bedding
Milking, milk cooling
Farm buildings
Total Energy Use
Yield (kg)
Energy Use (MJ/kg)
Source: Jørgensen et al (2005, Biomass and Bioenergy 28, 237–248,
http://www.sciencedirect.com/science/journal/09619534)
3.6
2.4
1.0
2.7
7.4
0.4
8.0
2.5
2.3
1.5
0.8
3.3
6.7
0.4
8.0
2.5
28.0
9000
3.1
25.6
9000
2.8
Table 7.9 Comparison of measured energy inputs and
yields for current conventional and organic farming in
Denmark, and as expected for future organic farming.
Conventional
Organic now
Organic future
Conventional
Organic now
Organic future
Conventional
Organic now
Organic future
Conventional
Organic now
Organic future
Energy Use
Yield
Energy
Energy
(GJ/ha)
(GJ/ha) Input/Output Output/Input
Grass/Clover
15.2
81
0.187
5.3
4.0
65
0.062
16.3
4.2
71
0.059
17.0
Cereals
12.7
63
0.203
4.9
6.3
43
0.148
6.7
6.4
49
0.131
7.6
Row crops
21.9
130
0.169
5.9
15.2
121
0.125
8.0
15.6
121
0.129
7.8
Permanent Grass
1.8
25
0.072
13.9
1.1
23
0.049
20.5
1.1
23
0.049
20.5
Source: Daljaard et al (2002, in Economics of Sustainable Energy in Agriculture, Kluwer
Academic Publishers, Dordrecht, The Netherlands)
Table 7.10 Comparison of energy inputs (MJ/kg) and yield (t/ha) for
corn in southwestern Ontario, Canada, using chemical fertilizers or
swine manure.
Seeds
Starter fertilizer
Fertilizer
Grain drying
Herbicides
Fuel
Total (MJ/kg)
Yield (t/ha)
Course Soil
Chemical Manure
0.31
0.33
0.12
0.06
0.75
0.00
0.59
0.59
0.28
0.29
0.11
0.15
2.16
1.41
8.84
8.44
Medium Soil
Chemical Manure
0.35
0.33
0.06
0.06
1.58
0.00
0.61
0.59
0.20
0.18
0.12
0.14
2.92
1.29
7.90
8.34
Fine Soil
Chemical
0.40
0.52
0.92
0.59
0.24
0.14
2.81
6.78
Source: McLaughlin et al (2000, Canadian Agricultural Engineering 42, 9–17)
Manure
0.40
0.53
0.00
0.58
0.24
0.16
1.91
6.82
Table 7.11 Comparison of energy inputs (GJ/ha) during the last 5year rotation in a 32-year field experiment involving winter barley,
winter wheat, and sugar beets in Germany on relatively fertile soil
using either chemical fertilizers or manure.
Seeds
F e r tiliz e r
H e r b ic id e s
Fuel
M a c h in e s
To t a l ( G J /h a )
D r y y ie ld ( t/h a /y r )
C h e m ic a l
1 .1 2
9 .4 3
0 .9 3
4 .2 2
1 .8 1
1 7 .5 1
1 0 .8 0
M anure
1 .1 2
4 .1 3
0 .9 3
4 .6 8
2 .5 4
1 3 .4 0
1 0 .8 5
Source: Hülsbergen et al (2001, Agriculture Ecosystems and Environment 86, 303–321)
Summary on low-input farming systems
• There is typically a 35-50% reduction in the energy
required to produce a given amount of food using
organic methods compared to conventional methods
• Yields (food production per unit of land area) typically fall
by 10-20% (sometimes by 35%,sometimes not at all)
• However, current crop varieties have been optimized
through breeding for conventional systems of production.
Re-optimization for organic systems may result in no
reduction in yield
• If this is insufficient, modest reductions in meat
consumption could readily compensate for decreases in
agricultural yields due to a shift to organic agriculture
Energy Use by Fisheries
• Fish are one of the most energy-intensive food
products
• Energy intensities have increased in recent years due
to the use of larger ships (one huge shipped trawling
until it is full carries more tonne-km of cargo than
many smaller ships with the same total capacity) and
the greater distances travelled now from the home port
for most fleets
• Extermination of the world’s commercial fisheries will
occur by 2050 if current trends continue (algae will
take over the oceans)
• As the remaining stock is further depleted, the energy
expended for tonne of fish harvested will increase
further
Table 7.12 Ratio of fossil fuel energy input to protein energy
output for various US fisheries.
Fishery
Herring
Perch (oceanic)
Salmon (pink)
Cod
Tuna
Haddock
Halibut
Salmon (king)
Shrimp
Lobster
Input/Output Ratio
2:1
4:1
8:1
20:1
20:1
23:1
23:1
40:1
150:1
192:1
Source: Rawitscher and Mayer (1977, Science 198, 261–264)
Table 7.13 Ratio of fossil fuel energy input to protein energy output for
various aquaculture fisheries.
Fishery
Pond polyculture, Israel
Catfish, Louisiana
Sea bass, Thailand
Shrimp, Thailand
Oyster on land, Hawaii
Prawn, Malaysia
Lake Perch, Wisconsin
Input/Output Ratio
10:1
34:1
65:1
70:1
89:1
130:1
189:1
Source: Pimental and Pimental (2008, Food, Energy, and Society, 3rd Edition,
CRC Press, Boca Raton)
Role of diet
Figure 7.12 Phytomass energy flows in the world food system.
Source: Wirsenius (2003, Journal of Industrial Ecology 7, 47–80)
Table 7.15 Ratio of phytomass energy input to the metabolizable
energy of animal products consumed by humans (MJ/MJ).
Region
East Asia
Eastern Europe
LA + Caribbean
N Africa + Mid East
North America +
Oceania
S&C Asia
SubSaharan Africa
Western Europe
Weighted world
average
Animal Product
Fatty Fatty Fatty
Poultry Beef
Pork Poultry
20
67
8.3
9.1
18
36
7.7
7.3
17
59
12
7.7
20
59
8.3
9.1
Beef
145
71
125
133
Pork
22
21
36
22
59
227
172
56
16
31
33
16
13
24
26
12
31
104
77
29
6.3
11
11
6.3
117
21
17
55
7.9
Milk
7.7
6.7
9.1
10
Eggs
7.7
7.7
7.1
7.7
6.7
11
11
5.9
4.8
10
19
5.3
5.9
9.1
10
5.3
8.0
7.7
7.4
Source: Computed from data in Wirsenius (2000, Human use of land and organic materials,
Ph D Thesis, Chalmers University of Technology, Göteborg, Sweden)
Table 7.16 Food energy consumption (including losses by wholesalers
and beyond) and phytomass energy requirements for different diets
assuming inverse efficiencies of 1.5 for plant food, 7.7 for dairy
products and 44.6 for land meat products.
Current
Diet Scenarios
Average Vegan Vegetarian Moderate Affluent
Wholesale Food Energy Supply (MJ/person/day)
Plant energy
10.95
13.10
11.90
9.44
6.84
Land meat energy
1.04
0.00
0.00
0.60
2.20
Seafood energy
0.12
0.00
0.00
0.06
0.06
Dairy energy
0.99
0.00
1.20
3.00
4.00
Total
13.10
13.10
13.10
13.10
13.10
Required phytomass (MJ/person/day)
Related to plant food
16.4
19.7
17.9
14.2
10.3
Related to meat food
46.3
0.0
0.0
26.8
98.1
Related to dairy
7.6
0.0
9.2
23.1
30.8
Total
70.3
19.7
27.1
64.0
139.2
Figure 7.13 Diet and waste in the food system
16
Food Energy Supplied (MJ/person/day)
Losses
14
Plant products
Dairy products
12
Meat
10
8
6
4
2
0
North
America +
Oceania
Western
Europe
Eastern
Europe
N Africa +
Mid East
LA +
Caribbean
East Asia
South & SubSaharan
Central Asia
Africa
Figure 7.14a Trends in global meat consumption
Annual Consumption (Mt)
300
250
Terrestrial meat
Ocean fisheries
200
Aquaculture
150
100
50
0
1960
1970
1980
1990
Year
2000
2010
Figure 7.14b Trends in total global and average per
capita meat consumption
500
100
400
80
Per Capita Meat Consumption
300
60
200
40
100
20
0
1960
1970
1980
1990
Year
2000
0
2010
per capita consumption (kg/yr)
World Meat Consumption (Mt)
World Meat Consumption
Figure 7.15 Per capita meat consumption
in various countries
180
Annual per capita consumption (kg)
160
Seafood
140
Land meat
120
100
80
60
40
20
0
Japan
US
China
EU
India
Estimates of the total energy inputs for
the production of different food products
Table 7.21 Estimated lifecycle secondary energy inputs for food consumed
in Sweden and the UK up to the point of delivery to retail outlets. The
lifecycle energy inputs given here do not include phytomass inputs.
Food Group
Meat from land
Meat from oceans
Cheese
Eggs
Milk
Legumes
Other Vegetables
Fruit, unspecified
Fruit, air freight
Fruit, ship
Fruit, local
Breakfast cereals
Cereals
Breads
Sweets
Lifecycle Energy
(MJ/kg)
Sweden
UK
13-75
45-109
19-220
75-150
60-65
75
18
58
5-6
7-8
5-20
22-33
11-60
9-35
9-31
29-115
9-10
5
2.5-37
25
2-7.5
10-25
9-21
10
1-44
13-190
Figure 7.16 Energy embodied in a can of corn
Production
Processing
Packaging
Transportation
Distribution
Shopping
Home preparation
TOTAL
Food energy in corn
0
2000
4000
6000
8000
10000
12000
14000
Energy (kJ)
Source: Pimental and Pimental (1996, Food Energy, and Society, 2nd Edition, University Press of Colorado, 186–201)
Figure 7.17a GHG emissions per MJ of food energy
Equivalent CO2 Emission (gmC/MJ)
900
N2O from manure
800
CH4 from manure
CH4 from enteric fermentation
700
Fossil fuel
600
500
400
300
200
100
0
Beef
Sheep
Pork
Eggs
Dairy
Poultry
Equivalent CO2 Emission (gmC/gm
protein)
Figure 7.17b GHG emissions per gm of food protein
50
45
N2O from manure
CH4 from manure
40
CH4 enteric fermentation
Fossil fuel
35
30
25
20
15
10
5
0
Beef
Sheep
Pork
Eggs
Dairy
Poultry
Figure 7.18 GHG emission per litre of beverage
Equivalent CO2 emission (gmC/litre)
350
300
250
200
150
100
50
0
Milk
Beer
Coffee
Juice
Soft drinks
Bottled
water
Figure 7.19a Personal energy use, USA in 2002
Primary Energy (GJ/person/yr)
100
80
60
40
20
0
Figure 7.19b Personal energy use, Australia in 1993
Primary Energy (GJ/person/yr)
50
40
30
20
10
0
Figure 7.19c Personal energy use, UK in 1996
Primary Energy (GJ/person/yr)
50
40
30
20
10
0
Figure 7.19d Personal energy use, Sweden in 1996
Primary Energy (GJ/person/yr)
50
40
30
20
10
0
Figure 7.20. Comparison of per capita energy use in
supplying food in different countries
Food Primary Energy (GJ/person/yr)
40
35
30
25
20
15
10
5
0
The preceding estimates of energy input account for all the
energy used to produce the crops that are fed to animals,
but do not count the energy of the crop phytomass itself.
However, the crop phytomass has energy value and so
could be used as a solid biofuel, or the land used to
produce the food for animals could instead be used to
produce bioenergy crops that are more suitable as an
energy source
In the following table, the energy inputs used to produce
different animal products are combined with the energy
value of the food that is fed to the animals
Table 7.22 Phytomass feed requirements per MJ of animal product when fed
grain or allowed to graze on pasture, and fossil fuel energy and total energy
inputs per MJ of animal product. Two forage entries are given for beef, the first
for high-quality pasture and the second for low-quality pasture.
Phytomass (MJ) per
Animal MJ of animal product
Product Grain
Forage
Lamb
36
51
Beef
22
50
335
Turkey
14
Egg
32
Pork
11
Dairy
4.7
6.6
Poultry
7.3
Fossil energy
input per MJ of
animal product
21
12
6.2
4.4
13
3.4
3.1
3.0
Total energy input (MJ)
Total energy input (MJ)
per MJ of animal product per kg of animal product
Grain
Forage
Grain
Forage
57
72
601
763
34
63
366
672
341
3666
18
90
45
279
14
140
7.8
9.8
21
26
10.3
58
Table 7.23 Comparison of annual energy use by a family of four.
Secondary energy use
Food, excluding
phytomass input
Food, including
phytomass input
Housing heating
(200 m2 floor space)
Transport
Vacations
Low: 12 MJ/person/day
High: 50 MJ/person/day
Low: 29 MJ/person/day
High: 182 MJ/person/day
Low: 15 kWh/m2/yr
High: 75 kWh/m2/yr
15,000 km/yr by car@8 l/100 km
Long-haul flight (10,000 km return)
Annual primary
energy use (GJ)
Low
High
29
112
Difference
(GJ/yr)
83
60
315
255
14
65
51
-
61
24-36
61
24-36
Summary of Energy and Environmental
Impacts of Meat-based vs Vegetarian Diets
• Greater requirements for fertilizers, pesticides and water (to
produce the phytomass that is fed to animals) (corn, most of
which is fed to cattle, has one of the highest N requirements)
• Impacts of fertilizer runoff on coastal oceans (anoxic dead
zones)
• Waste disposal problems and difficulty/impossibility of
recycling nutrients in intensive animal production systems)
• Much greater land requirements – a driving force (for
example) of Amazon deforestation (much of which is to
produce cattle for export to North America, or to produce
soybeans that are fed to cattle in North America)
• Current levels of fish consumption are unsustainable,
threatening eventual collapse of marine ecosystems and
already threatening other species that depend on some of the
same fish species
Other considerations:
• Health:
- High levels of consumption of red meat are associated
with greater incidence of colorectal cancer
- Hormones in grain-fed beef are hazardous (pregnant
women should not eat such meat)
- However, personal health will be worse if the wrong kinds
of foods (especially starchy and sugary foods) are
substituted for meat
• Ethics
- Degrading treatment of animals prior to slaughter in the
energy- and land-efficient, intensive meat production
systems
- Killing other sentient beings merely for one’s personal
pleasure (i.e., the taste of meat)
Localized vs Globalized Agriculture
•
•
•
•
•
•
•
•
•
Distance transported
Efficiency of transport and of the distribution system
Differences in land productivity in different regions
Differences in the energy efficiency of the production
system in different regions
Differences in energy used for packaging
Energy used for storage or in greenhouses for locallyproduced food
Food losses during storage and transport
Comparison with energy use by consumers driving to
and from a grocery store
Meeting nutritional requirements of vegetarian and
vegan diets
Table 7.24 Comparison of the energy inputs (embodied energy) in
providing locally-produced apples in Europe and apples imported from
New Zealand by ship. Losses during transport and storage are
neglected here.
Apples grown in Europe
Initial cultivation
Transport to coldstore
Initial cooling
Cooling in storage
Transport to Europe by ship
Cooling during transport
Transport to RDC
Transport to retail outlet
Packaging
Total (MJ/t)
Input data
1070 MJ/t
3.47 MJ/t/km x 40 km
86.3 MJ/t
(5.4 MJ/t/day) x
(10-350) days
1.2 MJ/t/km x 100 km
1.2 MJ/t/km x 150 km
650 MJ/t
MJ/t
1070
138.8
86.3
541890
0
0
120
180
650
22994135
Apples imported from New
Zealand
Input data
MJ/t
470 MJ/t
470
3.47 MJ/t/km x 40 km
138.8
86.3 MJ/t
86.3
5.4 MJ/t/day x
10 days
54
0.11 MJ/t/km x 23000 km
2530
10.8 MJ/t/day x 28 days
302.4
1.2 MJ/t/km x 250 km
300
1.2 MJ/t/km x 150 km
180
650 MJ/t
650
Source: Canals et al (2007, Environmental Science and Pollution Research 14, 338–344)
4702
Other considerations in the choice of local vs
imported food when the imported food comes
from developing countries:
• Production and export of food from countries with warm
climates and lots of sunshine (such as in Africa) could be a
significant source of employment and income for these
countries
• This in turn could spur large increases in agricultural yields,
thereby reducing overall land requirements for agriculture
(and will indirectly lead to lower rates of population growth
– and eventual population stabilization – in the future)
• However, today some poor countries export food to the
developed world while some of their own people go hungry
Supplemental figure: trends in agricultural
yield in different world regions
4000
3500
World
All developing
3000
South Asia
Yield (kg/ha/yr)
Sub-Saharan Africa
2500
2000
1500
1000
500
0
1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 2001 2005
Year
Source: Hazell and Wood (2008, Phil. Trans Roy. Soc. B, 383, 495-515)