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In the last 5 0 years, the global production of cereals
tripled (from 631 million tonnes in 1950 to 2 029 mil-
lion tonnes in 2004) and the current situation forces
us to pay attention to the adoption of sustainable
agricultural practices and natural resources (en-
ergy, climate, water, soil and biodiversity).The energy efficiency of the food system
From an energy efficiency standpoint, the modern
food system is one of the least effective industrial
systems: it consumes more energy than it produces.
One indicator of the unsustainability of the modern
food system is the Sustainability Index (SI), the ratio
of energy inputs (the energy required to produce a
food divided by the energy content of a food product,
evaluated in calories).
In the last century (1910–2010), this indicator has
increased from close to 1 for traditional pre-indus-
trial societies at the beginning of the last century to
a value close to 9 in the 1970s, to arrive, today, to a
value equal to, and sometimes higher than 1 00.The food system and global warming
A study on the environmental impact of the products
and services used in the EU-25 (cited in Moresi and
Valentini, 2010) has evidenced how the food and
drink, tobacco and narcotics are collectively re-
sponsible for 22–31 percent of global warming.
Among these products, meat and meat products
have the largest environmental impact of the total
consumption, their estimated contribution to global
warming (GWP^1 ) being close to 12%, 24% of Eu-
trophication Potential (EP^2 ) and 10% of Photochem-
ical Ozone creation potentials (PCOP^3 ). Dairy
products contribute some 5% to GWP, some 10% toEP and some 4% to PCOP. Cereal products (bread,
pasta, flours) contribute some more 1% to GWP and
PCOP, and close to 9% to EP. Finally, fruits and veg-
etables (including frozen ones) give a contribution
close to 2% to GWP, EP and PCOP.Consumer choices
Consumer choices could play a leading role. In 1986,
J. Gussow and K. Clancy introduced the term “sus-
tainable diet”: dietary choices could give their con-
tribution not only to health, but also to the
sustainability of the agricultural system. Their stud-
ies showed the strong link that exists between di-
etary choices and land use and conservation, water
management and energy resources. Recently,
owing to problems linked to the food system sus-
tainability, it was considered how changes in
lifestyles could influence greenhouse gas emis-
sions. In the United Kingdom, it has been calculated
that the CO2e emissions per capita due to dairy
products and meats consumption equal 2 19 4 kg
CO2e, whereas those due to vegetable products
consumption (cereals, fruits and vegetables) corre-
spond to 450 kg CO2e. A diet with a 30 % decrease in
animal products and a 15% increase in vegetables
would allow a reduction of emissions of 5 90 kg CO2e
per capita per year. This reduction would be equiv-
alent to a total decrease of 5% of the global emis-
sions per capita, equal to 10.3 Mg CO2e expected in
2 008. Dietary choices aimed at reducing CO2e emis-
sions must however be formulated guaranteeing
nutritionally balanced menus.Sustainability indicators
In recent years, some indicators were developed in(^1) Global warming potential (GWP) is a measure of how much a given
mass of greenhouse gas is estimated to contribute to global warming.
The global warming potential is calculated in carbon dioxide equiva-
lents (CO2-Eq.). This means that the greenhouse potential of an emis-
sion is given in relation to CO2. Since the residence time of the gases
in the atmosphere is incorporated into the calculation, a time range
for the assessment must also be specified. A period of 100 years is
customary.
(^2) Eutrophication Potential (EP): Eutrophication is the enrichment of nu-
trients in a certain place. Eutrophication can be aquatic or terrestrial.
Air pollutants, waste water and fertilization in agriculture all contribute
to eutrophication. The eutrophication potential is calculated in phos-
phate equivalents (PO4-Eq).
(^3) Photochemical Ozone creation Potential (PCOP): photochemical ozone
creation potential (POCP) is measured in ethylene-equivalents (C2H4-
Eq.). Despite playing a protective role in the stratosphere, at ground-
level ozone is classified as a damaging trace gas. Photochemical ozone
production in the troposphere, also known as summer smog, is sus-
pected to damage vegetation and material. High concentrations of
ozone are toxic to humans.