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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

50

60

70

water energy land0

10

20

30

40

50

60

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.