THE CALCULATOR
Modifying our alimentation requires two things: motivation (which is often associated with cultural habits) and access to information allowing to make optimal choices.
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The calculator offers a way to know precisely what is the ecological footprint of one meal on our environment and if it produces a reserve or a deficit in biocapaciy. At this scale, the data obtained are easily understandable for individuals and food professionals, allowing a more global view with factors such as budget and energetic intake.
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The Ecological Footprint thus adds to this facilitated understanding by indicating the surface needed to produce one meal, and the number of planets that would be necessary if every human being was to eat the same thing.
WHAT IS THE
ECOLOGICAL FOOTPRINT ?
The Ecological Footprint is an index designed to represent the pressure that people put on their environment with their alimentation. It is measured by taking into account the surface needed to produce what is consumed, but also the pollution associated with this production and the transportation of it.
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The index is thus composed by two aspects: a “land” aspect (i.e. the surface used to produce the raw materials) and an “energetic” aspect (i.e. the surface of forrest needed to absorb the CO2 produced in the production process and the transportation).
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Then the Ecological Footprint of each person is compared to the biocapacity of our planet.
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Learn more about the Global Footprint Network here
Calculation of EF(m), the Ecological Footprint per meal.
The calculation of the ecological footprint consists in a cross multiplication. Based on the ecological footprint per kilograms for each ingredient and for each type of origin, we get the ecological footprint for each ingredient according to its origin and its mass.
We get this equation:
With:
• n the number of ingredients making up the meal
• EF(Tx) the ecological footprint for 1kg of the ingredient x of type T (in global square meter)
• Mx the quantity of the ingredient x (in grams)
• Px the ecological footprint of the transportation depending on the origin of the ingredient x (in global square meter)
• EF(m): the ecological footprint of its meal.
Calculation of the sustainability index
Once the ecological footprint of the meal is calculated, it has to be compared with the biocapacity per meal and per person in order to assess whether this meal results in a deficit or a reserve of biocapacity
We get this equation:
With:
• B the biocapacity per meal and per person (in global square meter)
• EF(m): the ecological footprint of the meal (in global square meter)
• FSI the Food Sustainability Index (in global square meters)
If the result is negative, it means that there is a deficit of biocapacity
If the result is positive, it means that there is a reserve of biocapacity
LET'S DO THE MATH
THE DATAS
Collecting the relevant data is the most difficult part of this project.
The data available online is not always complete and does not always measure specifically the information needed for the calculator. Thus, for now, the Meal’Impact team has collected some substitute information which gives an indication of what is measurable. It would however need a partnership with an organisation or a university to get the specific information needed.
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Types of ingredients (T) and the specific ingredients (x)
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There is some databases established to calculate the food carbon footprints, the water footprint, as well as the WWF study on the food production needed areas (even so those calculations are not completely proved as reliable yet).
The aggregation of those different datas has lead to the development of differents types of food, ranks by dismissing ecological footprints (by the kg CO2-eq/kg produce or bone free meat)
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Beef
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Pork
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Poultry and fish
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Eggs and dairy
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Cereals
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Fruits and vegetables
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Ecological footprint for 1kg of the ingredient x of type T (EF(Tx))
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However, the lack of food carbon footprints official sources prevented us to associate values to those categories. Thus, we should gather those datas by studying, the average crop superficie needed for every types of food, the average superficie needed for the marketing and the conservation, as well as the needed superficie of forest to absorb the C02 emitted (without including pollutant emission by transportation )
As suggested above, the data collected does not exactly provide this information, but it allows a relative assessment of the ecological footprint of various ingredients.
The data in the table comes from a research published in 2016, which itself tried to synthesise all the information available in the various scientific publications worldwide, and focused on providing the Global Warming Potential (GWP) values for various fresh food categories. The values are here classified by type and by decreasing order.
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All the datas are available here
Ecological footprint for transportation depending on the origin of the ingredient x (Px)
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Which means the needed forest superficie to absorb the CO2 emitted by the transport of the food. We know that one hectare of forest needed can absorb, in average, 24 tonnes of CO2 for a year.
Then, we must calculate the average food emission per KG, of an average local truck journey of 100km, then the average national truck journey of 500 km, the average journey of 1500 km still by a truck and the average journey of a plane on 1500 and 3000 km.
Biocapacity per meal and per person (B)
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As said in the National Footprint Account Results (Edition 2016), in 2012 the biocapacity for an individuals in a year was 1.7 hag. Then, by divided this data by the meals number in a year, they obtained 17000/ (365X3)= 15.5m². Thus, this should be the biocapacity of a meal by one person in 2012. Today, this result would probably be lower because of the demographic rise.