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1|07-11-2016
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faculty of mathematicsand natural sciences
energy and environmental sciences
07-11-2016
Why becoming a vegetarian is not going to save the world.
Sanderine Nonhebel and Winnie Leenes
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Production of food puts large claim on environment
› It uses:› 30 % of the land› 70 % of the fresh water› 20 % of the energy
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Production of food puts large claim on environment
› Is major cause for
› Deforestation› Eutrophication› Acidification› Erosion› Desiccation› Decline biodiversity
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› Food causes the largestenvironmental impact of our totalconsumption
›However, stop consuming food is notan option.
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Huge challenge:› Enough healthy food for the global
population, without destroying the globalenvironment.
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Can we reduce theenvironmental impact of ourfood by changing ourconsumption pattern?
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What is the environmental impact of individual food items?
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Method: chain analysis› Determine land, water and energy required in
the whole production chain.
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Typical values resource use food items
EnergyMJ/kg
Land m2/kg
Water l/kg
Vegetables 5 0,2 100Bread 18 1,1 600Potatoes 2 0,2 80Rice 20 3 3000Veg. oil 30 10 3000Meat 90 12 8000Milk 10 1,3 600Coffee 38 16 17000
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A luxurious diet requires more resources than a basic one.
› Wheat as livestock feed (5 kg of wheat for 1 kg of meat)
› More energy for growing, storing, transport preparation
› More packaging
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0500
1.0001.5002.0002.5003.0003.500
1961 1971 1981 1991 2001
Western Europe
Source: Kastner T, Ibarrola Rivas MJ, Koch W, Nonhebel S (2012) Global changes in diets and the consequences for land requirements for food. Proceedings of the National Academy of Sciences. Available at: http://www.pnas.org/cgi/doi/10.1073/pnas.1117054109
0500
1.0001.5002.0002.5003.0003.500
1961 1971 1981 1991 2001
Consumption in kcal Land use for this consumption
meat
cereals
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Reduction meat consumption reduces environmental impacts of food
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Vegetarian meals become popular› Restaurants› Cantines› Shops› Policy › Recipies
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What is the environmental impact of a vegetarian meal?
2 menusPotato, cabbage, sausage
Rice, cashew nuts, spinace cheese
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0
10
20
30
40
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60
70
water energy land0
10
20
30
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70
water energy land
Resource use› sausage › vegetarian
sausage nuts
cheese
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The resource use of the vegetarian meal is higher!
› These results can also be found for many more vegetarian recipies
25|23-05-2016faculty of mathematicsand natural sciences
energy and environmental sciences
That is why becoming a vegetarian is not going to save this world.
There is a strong need for resource saving recipies.
