Environmentally friendly food – what is it?

1.1 - Food
Environmentally friendly food – what is it?
Environmentally friendly food can be defined in terms of the choice of food item, how this item
was produced, its origin, the transportation means, and the type of storage and cooking method
used. Each of these characteristics influences the amount of greenhouse gas emissions that can
be attributed to a particular food item. The impact difference between each product can thus vary
by a factor of 150i. This means that if the product with the lowest environmental impact is
responsible for an emission of 1 kg CO2 per 1 kg product, then that with the highest negative
impact results in the emission of 150 kg CO2 per 1 kg product.
So now the question is: of all the possible choices that can be taken to eat in an environmentally
friendly way, which have the most decisive influence?
The two factors with the largest impact include:
1. The choice of ingredients – eat more vegetable than animal products
2. Seasonality – eat more seasonal vegetables and fruits
Go Veggie – better to eat vegetarian food than that of animal origin
The first factor significantly influencing the environmental impact of what we eat is the ingredient
choice: vegetarian food has a decisively lower impact than food products of animal origin. This
difference is mainly due to the fact that animal products convert energy into a form that is used by
humans in a less efficient way than that provided by the vegetarian options. Only 10% of the
energy in one trophic level can be transferred to the next level of the pyramid. This means that, for
example, 100kg of wheat are needed to produce 10kg of a breeding animal.
Figure 1
Trophic Pyramid representing the conversion of biomass across levelsii
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1.1 - Food
Figure 2
Amount of different types of food that can be produced from 1m2iii
Annex I, found at the bottom of the page, shows the greenhouse gas (GHG) emissions caused by
the production of different food products. You can see that, in general, animal derivates result in
higher emissions, while vegetable products are largely more efficient in converting energy into
food. It is also clear that there are large differences between different types of meat: 100g of beef
has an impact 4 times that of chicken, pork or fish.
Finally, in addition to the type of products being consumed, the quantities of consumed
ingredients also matter. A menu always contains several ingredients. An environmentally friendly
product doesn’t necessarily have to mean – no meat – but could instead be an equal ratio
between different types of ingredients allowing for both the appreciation of fine food, while at the
same time doing something good for the environment.
Eat Seasonal – avoid air transported, greenhouse cultivated, and long term storage food items
Within the vegetables and fruits (V&F) category, the options with the best environmental
performance are seasonal V&F. The highest GHG emissions linked to V&F are due to imports by air,
followed by cultivation in greenhouses heated using fossil fuels and the use of energy intensive
storages, such as freezers. Thus, by eating seasonal we can do a lot of good things all at once. For
example:
•
A pear imported from South Africa by plane causes 40 times more emissions than a pear
grown in Switzerland and purchased during its seasoniv.
•
The use of greenhouses for cultivating tomatoes is very common making it difficult to find
alternative production types in the grocery store. However, we can still reduce our impact
by choosing to avoid buying tomatoes when they are not in season. Buying fresh Swiss
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1.1 - Food
tomatoes grown in a greenhouse in December causes 5 times more emissions than
tomatoes grown in Augustv.
•
Storage impacts become apparent when comparing fresh and frozen products: longer
storage can increase emissions by up to double the total emissions of the same product,
depending on the time spent in the freezervi.
The following figure shows the average emissions of a set of vegetables and cultivated fruits,
transported and preserved in different ways.
Emission factor of Vegetables and fruits
Seasonal
Frozen
Canned
Greenhouse
EU truck
Short distance
flight
Long distance
flight
0
5
10
15
20
25
factor of g CO2 eq. / g vegetables and fruits
Figure 3
Emission factors of an average portion of vegetables having different type of
cultivation, transport and storagevii.
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http://www.numufu.com/wp-content/uploads/2011/07/trophicpyramid.jpg
iii
http://www.its-my-part.ch/de/wissen/fleisch/
iv
Dr. N. Jungbluth 2011. Environmental Friendly food consumption: What does this mean for
consumers?.ESU-services Ltd. Uster, Switzerland.
v
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vi
Dr. N. Jungbluth 2011. Canteen Meals: comparison of vegetarian and meat based recipes,
Environmental Friendly food consumption: What does this mean for consumers?.ESU-services Ltd.
Uster Switzerland.
vii
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ii
http://www.weact.ethz.ch/
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