Frequently asked questions
CO2e means carbon dioxide equivalents and is the measure for greenhouse gasses.
Whilst carbon dioxide is the main greenhouse gas, there are many others including methane and nitrous oxide. In order to properly assess the ‘global warming potential’ (GWP) of a product, all the greenhouse gasses must be assesed. Therefore, all the gasses produced are converted into carbon dioxide equivalents, allowing us to create a single value explaining the GWP of the product.
You can read more about this on the Eurostat website.
‘Life cycle assessments’ are used to calculate the environmental impact of a food or product. These studies look at different stages of a food’s life cycle, including how the food is grown, packaged, transported, stored, and cooked, and use this to calculate its carbon footprint.
Most life cycle assessments are completed against the ISO 14044 guidelines, which helps to standardise how the calculations are completed.
We have collected together the results from different life cycle assessments, published mostly in peer-reviewed journals. You can find a full list of our sources in our references section, below.
We have then modelled the given values so they cover every stage of the life cycle. We then average the results to get one carbon footprint value for each food at each stage of the life cycle.
Where you live impacts the actual carbon footprint of your food. Most of the variance comes from different local farming and processing techniques and the land use change. Differences can also come from the energy used, local packaging, transport distances (especially if air-freighted), and more.
Our goal is to have the average emissions of each food in each region. Currently, we have a global average for each food, which reflects the current state of food emissions research. We also have some specific values for foods grown or consumed in the UK, and are actively researching more region-specific values.
Greenhouse gas (GHG) emissions are a crucial part of your diet’s sustainability and something everyone should be thinking about. However, there are also many other things to consider, such as the water footprint, eutrophication, impact on biodiversity, and more.
We realise it can also be difficult to understand these factors and are working hard to also display this information for you. Where possible, we will also post about this on our blog.
The main reason that food carbon footprint labels are so rare is the research is so time-consuming (and therefore expensive!). You can read more about this on our blog.
We’re developing a database of average food emission values and automating the data collection process. This makes it much quicker and, most importantly, cheaper to calculate the carbon footprint of food products and recipes, which we hope will mean carbon labels become much more common.
FAQs for our recipe blog carbon labels
The carbon footprint values are based on the global average emissions of each food. This reflects the current state of food emissions research and knowledge we have of where the food is grown and consumed.
Where you live does have a big impact on the actual carbon footprint of your food. In partcular, the different farming and land use change can have a big impact, as well as if the food is air-freighted.
Whilst there is some variance in the food’s emissions, the values will nevertheless be representative of the recipe’s emissions wherever you live.
To get a better idea of whether your food has a higher or lower footprint than average, check out our blog posts to see what factors we talk about that influence a food’s emissions.
The values displayed are based on the average emissions for each food, generally considering food grown in and out of season.
Food grown in season will likely have a lower impact than the value we used, so your meal will have a lower overall footprint. This is because extra energy is needed to re-create the right environment to grow food out of season, increasing the climate footprint.
When calculating the carbon footprint of a recipe, we take into account all the ingredients listed, including the optional ones. This is also what we recommend if users have added the ingredients themselves.
Where recipes have variable or inter-changeable ingredients, only one value is used. Either one ingredient has been selected, or an average of the foods is taken.
If a recipe has optional ingredients or you plan to adapt it, you can use our free food emissions calculator to work out the exact carbon footprint of your recipe.
We have used a range of reports and databases to generate an average emissions value for each food. All of our sources are referenced below. If you have any questions about our data or sources, please do not hesitate to get in touch.
Coelho C, Pernollet F, and van der Werf H, ‘Environmental Life Cycle Assessment of Diets with Improved Omega-3 Fatty Acid Profiles’ (2016) PLoS ONE 11(8): e0160397. https://doi.org/10.1371/journal.pone.0160397
dataFIELD database v1.0. An explanation of the methods used to construct the database can be found in Heller MC, Willits-Smith A, Meyer R, Keoleian GA, Rose D, ‘Greenhouse gas emissions and energy use associated with production of individual self-selected U.S. diets’ (2018) Environmental Research Letters 13. https://doi.org/10.1088/1748-9326/aab0ac
Foster C, Green K, Bleda M, Dewick P, Evans B, Flynn A, Mylan J, ‘The environmental impacts of food production and consumption: A report to the Department for Environment, Food and Rural Affairs’ (2006) DEFRA Project EV02007
Graham F, Russell J, Holdsworth M, Menon M, Barker M, ‘Exploring the Relationship between Environmental Impact and Nutrient Content of Sandwiches and Beverages Available in Cafés in a UK University’ (2019) Sustainability 11(11), 3190. https://doi.org/10.3390/su11113190
Green R, Joy E, Harris F, Agrawal S, Aleksandrowicz L, Hillier J, Macdiarmid J, Milner J, Vetter S, Smith P, Haines A, Dangour A, ‘Greenhouse gas emissions and water footprints of typical dietary patterns in India’ (2018) Science of The Total Environment 643, 1411. https://doi.org/10.1016/j.scitotenv.2018.06.258
Ivan aan den Toorn S, Worrell E, and van den Broek M, ‘Meat, dairy, and more: Analysis of material, energy, and greenhouse gas flows of the meat and dairy supply chains in the EU28 for 2016’ (2019) Journal of Industrial Ecology. https://doi.org/10.1111/jiec.12950
Jelínková Z, Moudrý Jr J, Moudrý J, Kopecký M, and Bernas J, ‘Life Cycle Assessment Method – Tool for Evaluation of Greenhouse Gases Emissions from Agriculture and Food Processing’ (2016) IntechOpen. DOI: 10.5772/62300. Available here
Kramer GFH, Martinez EV, Espinoza-Orias ND, Cooper KA, Tyszler M, and Blonk H, ‘Comparing the Performance of Bread and Breakfast Cereals, Dairy, and Meat in Nutritionally Balanced and Sustainable Diets’ (2018) Frontiers in Nutrition, 5:51. https://doi.org/10.3389/fnut.2018.00051
Moberg E, Walker Andersson M, Säll S, et al, ‘Determining the climate impact of food for use in a climate tax—design of a consistent and transparent model’ (2019) Int J Life Cycle Assess 24, 1715. https://doi.org/10.1007/s11367-019-01597-8
Nielsen PH, Nielsen AM, Weidema BP, Dalgaard R and Halberg N, ‘LCA food database’ (2003), www.lcafood.dk [last accessed 10th May 2020]
Scarborough P, Appleby PN, Mizdrak A, et al, ‘Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK’ (2014) Climatic Change 125, 179. https://doi.org/10.1007/s10584-014-1169-1
Vetter SH, Sapkota TB, Hillier J, Stirling CM, Macdiarmid JI, Aleksandrowicz L, Green R, Joy EJ, Dangour AD, and Smith P, ‘Greenhouse gas emissions from agricultural food production to supply Indian diets: Implications for climate change mitigation’ (2017) Agriculture, Ecosystems & Environment 237, 234. https://doi.org/10.1016/j.agee.2016.12.024
Williams AG, Audsley E, and Sandars DL, ‘Determining the environmental burdens and resource use in the production of agricultural and horticultural commodities’ (2006) Defra Project IS0205