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To calculate the greenhouse gas emissions from eating a veggie burger with bread every day for a year, we have multiplied the amounts of foods that need to be produced by the emission factors of the corresponding foods. We have assumed that a veggie burger consists of 100 g soy-based meat substitute and 60 g bread.
The annual consumption of bread and soy-based meat substitute is calculated by multiplying the amounts eaten per day by the number of days per year.
60 g bread per day × 365 days per year = 21.9 kg per year
100 g soy-based meat substitute per day × 365 days per year = 36.5 kg per year
The calculations show that annual consumption amounts to 21.9 kg of bread and 36.5 kg of soy-based meat substitute. This refers to the quantities actually eaten.
To meet this “final consumption”, more food needs to be produced, due to waste and losses in the supply chain between producers and consumers. Waste and losses refer to the proportion of the produced food that is not consumed for various reasons. To get an accurate picture of the climate impact, the emissions of what is not eaten must also be included. The following waste factors have been used:
– Waste of bread: 37%
– Waste of soy-based meat substitute:17%
These waste factors represent average values for the food industry in Europe and include producer, wholesale and consumer waste. A 37% wastage rate for bread means that 37% of all bread baked is not eaten. A reduction of 37% gives the change factor (1 − 0.37). The amount of bread that needs to be baked is calculated by dividing the amount ultimately consumed by this change factor. The amount of soy-based meat substitute that needs to be produced is calculated in the same way.
21.9 kg/(1 − 0.37) ≈ 34.8 kg bread
36.5 kg/(1 − 0.17) ≈ 44.0 kg soy-based meat substitute
The calculations show that in order for one person to eat a veggie burger with bread every day for one year, 34.8 kg of bread and 44.0 kg of soy-based meat substitute must be produced.
The greenhouse gas emissions from food production are calculated by multiplying the total quantities of bread and soy-based meat substitute produced by their respective emission factors.
– Emission factor for bread: 0.80 kg CO2e per kg
– Emission factor for soy-based meat substitute: 2.14 kg CO2e per kg
The emission factors include the emissions from wheat and soy cultivation, production of input materials, processing, and transportation.
34.8 kg bread per year × 0.80 kg CO2e per kg bread ≈ 28 kg CO2e per year
44.0 kg soy-based meat substitute per year × 2.14 kg CO2e per kg soy-based meat substitute ≈ 94 kg CO2e per year
The total emissions are finally calculated as the sum of the emissions from the production of bread and soy-based meat substitute.
28 + 94 kg CO2e per year = 122 kg CO2e per year
The calculation shows that the total emissions amount to 122 kg CO2e per year, which has been rounded to 120 kg CO2e on the card.
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