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Calculations and data sources for food and drink

Learn more about the algorithm we use to calculate footprints in the food and drink category, which data sources are used and which we plan in the future.

Calculations for food and drink

Our calculator uses the amount of calories consumed by a person as an indicator of greenhouse gas emissions, where the average daily intake for a Norwegian is around 2700 kcal. The calories are divided into different food categories, and the CO2intensity for the food is used to find the footprint. Based on a detailed dietary study, we have initially chosen to count children aged 0-17 years as 65% of an adult.

We have used Aurelie Stamm's study of the average climate footprint in a Norwegian diet as a starting point for the amount of each food group that makes up an individual's diet. We use six main categories for foods; cereals, fruits and vegetables, meat, fish, eggs and dairy products, and beverages. This is again broken up into a number of subcategories. Using a comprehensive list of foods and associated CO2 intensities, we can calculate the footprint of an average Norwegian diet by adding together how much you eat in each category with the emissions it constitutes. The emissions are based on average figures from life cycle analyzes, specifically for Norway where the data are found.

Food waste is calculated using a waste factor for each of the 22 food categories. For the Norway data source, these numbers are obtained from Norwegian institutes Norsus and Matvett in their “Matsvinn i Norge” report (Norwegian only), so that we are able to distinguish between which categories are associated with a higher or lower level of food waste. For other data sources, a single waste factor is assumed to apply to all food categories. Reducing food waste reduces the overall footprint of an individual.

The food waste can be divided into food chain waste (in the food industry, at the distributors, and in grocery stores) and household waste. 

Transportation of food involves extra impact on the environment. The CO2-equivalent factors that Ducky uses incorporate transport related carbon emissions up to the border of Norway. In order to factor in the transportation to the place of consumption, a 10% increase is applied to the total footprint based on  Hamilton et al.

Our model constructs a vegetarian and vegan diet by redistributing calories from meat and possibly dairy products into relevant categories.

Data sources for food and drink

In addition to the general data sources listed above, data for the food module are sourced from Helsedirektoratet, NTNU, Matvett and the Public Health Institute England. Additionally, we have recently signed a collaboration with Matvett to get more accurate data on food waste. 

A complete overview of our data sources can be found here.

So far, only the proportion of children makes the food footprint of one region different from another. In the near future, our current sources will be supplemented by:

  1. Carrying out surveys in participating regions about the amount of meat and dairy products in the diet, as this drives the food footprint.
  2. Collaborate with grocery stores and wholesalers to access data on food sales in various categories.

As a municipality, you can contribute to a better calculation by supporting us in our work to obtain this data.