Food Carbon Calculator Rose Wu

Method and sources

The figures come from one global study of food systems. They are a world average and are not a figure for any one product.

What is counted

Each figure follows a food from the land to the retail store: land use change, animal feed, farm, processing, packaging, transport, retail and losses.

Cooking and consumer losses are not counted. Losses here means the extra food that has to be produced to deliver one unit to the consumer.

The formula

Emissions for one stage are that stage's figure per kg or litre multiplied by the amount entered. The running total adds the stages in order, and the total is the study's published mean for that food multiplied by the amount.

The stage figures and the total are published separately and can differ by up to 0.01 per kg or litre, so adding up the stages can come out slightly off the total. The last step of the running total is set to the total.

Greenhouse gases are combined into CO2 equivalents with the IPCC AR5 100-year factors, including climate-carbon feedbacks.

Some stages are negative, which means the stage removes more than it emits. They are shown with a minus sign and reduce the running total.

The range

The range is the production-weighted 5th to 95th percentile: the span within which most of the world's production of that food falls.

The mean is the average across all production. The median is the point with half of production below it. A few very high or very low producers move the mean more than the median, so the two can differ widely.

What one unit means

Each food is measured in the unit the study used. Nine are per litre, and the rest are per kg.

FoodUnit
Applesper kg of fresh fruit
Bananasper kg of fresh fruit
Beef (beef herd)per kg of fat- and bone-free meat and edible offal
Beef (dairy herd)per kg of fat- and bone-free meat and edible offal
Beer (from barley)per litre of beer
Beet sugarper kg of raw or refined sugar
Berries & grapesper kg of fresh fruit
Brassicasper kg of fresh vegetables
Bread (wheat & rye)per kg of bread
Cane sugarper kg of raw or refined sugar
Cassavaper kg of soil-free tubers
Cheeseper kg of cheese
Citrus fruitper kg of fresh fruit
Coffee (ground, roasted beans)per kg of ground, roasted beans, not brewed coffee
Dark chocolateper kg of dark chocolate
Eggsper kg of eggs
Fish (farmed)per kg of edible fish
Lamb & muttonper kg of fat- and bone-free meat and edible offal
Maize mealper kg of maize meal, as for polenta
Milkper litre of pasteurized milk (4% fat, 3.3% protein)
Nutsper kg of dry nuts, shell removed
Olive oilper litre of refined or filtered oil
Onions & leeksper kg of fresh vegetables
Other fruitper kg of fresh fruit
Other pulsesper kg of dry pulses, pod removed
Other vegetablesper kg of fresh vegetables
Palm oilper litre of refined or filtered oil
Peanuts (roasted)per kg of roasted peanuts, shell removed
Peasper kg of dry peas, pod removed
Pig meatper kg of fat- and bone-free meat and edible offal
Potatoesper kg of soil-free tubers
Poultry meatper kg of fat- and bone-free meat and edible offal
Rapeseed oilper litre of refined or filtered oil
Riceper kg of white or brown rice
Rolled oatsper kg of rolled oats
Root vegetablesper kg of soil-free tubers
Shrimp (farmed)per kg of head-free meat, shell-free for large shrimp
Soy milkper litre of soy milk (about 3.3% protein)
Soybean oilper litre of refined or filtered oil
Sunflower oilper litre of refined or filtered oil
Tofuper kg of tofu (about 16% protein)
Tomatoesper kg of fresh vegetables
Wineper litre of wine

Sources

Main data

Poore, J. & Nemecek, T. (2018), Reducing food's environmental impacts through producers and consumers, Science 360, 987-992. Paper at Science (DOI 10.1126/science.aaq0216). The author's page carries the paper, supplementary materials and data files.

The journal has published an erratum (science.aaw9908).

Stage figures: Our World in Data, Food emissions across the supply chain, based on Poore & Nemecek (2018). Our World in Data asks for credit to both itself and the original authors: Poore & Nemecek (2018), via Our World in Data. Percentiles, medians and sample sizes are from the authors' Data S2.

Comparison figures

These appear beside the main figure and are not mixed into it. Their boundaries and sometimes their units differ, so they are shown as published, per 1 kg or 1 litre.

AGRIBALYSE 3.2. Source ADEME, données AGRIBALYSE v3.2. Licence: Etalab 2.0. ADEME cautions that a single climate figure is not meant for consumer labelling or for comparing brands. ADEME on informing consumers, conditions of use.

SU-EATABLE LIFE. Petersson et al. (2021). Paper, data. Licence: CC BY 4.0.

CFLCAD. Chinese Food Life Cycle Assessment Database, Cai et al. (2022). Paper, data. Licence: CC BY 4.0.

The car comparison

The driving line uses the US EPA's figure of about 400 g of CO2 per mile for a typical passenger vehicle. That figure is CO2 only, while the food figure is CO2e, so the line is a sense of scale and not an exact match.

Photo credits

Photos come from Wikimedia Commons. Files are resized only; on the page they are cropped to fit, darkened and tinted. Where a food has no photo of its own source, the nearest one stands in and the description says what it really shows.