FAQ

Around 26-34% of global greenhouse gas emissions come from our food (source, source). There are small differences between the studies as to what proportion of land use is attributed to our food production. Overall, however, they agree that our diet has a strong influence on climate change.

Overall, it's not enough, but it's a good and usually quite simple start.

In order to be able to meet the 1.5°C target, we should produce around 1-1.5 tons of CO₂ per capita per year in the long term. At the moment, the average for the United States is 14 tons of CO₂ per capita, Australia and Canada both have approx. 15 tons of CO₂ per capita, while the United Kingdom is at 5 tons of CO₂ per capita (source). About 25-34% of emissions worldwide are due to our food system (source). So even if our diet no longer caused any CO₂ emissions at all, we would still be above the figure of 1.5 tons of CO₂ per person per year.

However, it is comparatively easy to generate significantly less CO₂ emissions by changing our diet: by making small to medium changes to our diet, we could generate 36-49% less CO₂ emissions in this area (source).

It is clear that it is not enough to simply eat in a more climate-friendly way. At the same time, it is relatively easy to try a different, more climate-friendly diet - you can start today, and you probably already have a lot of things in your pantry.

A carbon footprint expresses the greenhouse gas emissions associated with a particular thing or action. This makes it easier to compare: for example, we can say what the effect of growing a tomato is compared to driving a car.

The carbon footprint is usually expressed in CO₂ equivalents: All major greenhouse gases are converted to the climate effect of CO₂ so that there is a clear unit of measurement and we don't have to compare methane, CO₂, and so on in parallel. More specifically, the carbon footprint is usually expressed in kg of CO₂ equivalents per kg of food.

The CO₂ footprint can be determined using life cycle assessments: These are systematic studies of the environmental impact of products, including all upstream products and production steps. Such life cycle analyses are often carried out by scientists or research institutes and are often based on ISO or DIN standards.

I have collected data from various public sources. You can find the overview of CO₂ in food here - there are almost 2000 entries in total.

These data mostly come from scientific studies and usually represent a typical case: In individual cases, CO₂ emissions may differ depending on where and how the food is grown. This is why the overview sometimes contains several entries for the same food product.

To estimate the carbon footprint of each recipe, I use publicly available data on emissions from the production of ingredients and their preparation.

The carbon footprint of each recipe is only an approximation: we assume a certain amount of emissions for each food, but in fact this value also depends on how the food was produced (source). The value is therefore typical CO₂ emissions for this recipe, but certainly not accurate to the gram in individual cases.

Some parts of the cooking process are not shown because this depends on too many individual factors: the process of shopping (car or on foot, how many groceries in the same purchase, ...), the storage of the food in the home (how long in the fridge, ...), the emissions for the production of the dishes, cutlery and cooking utensils (knife, pan, ...), the washing up and food waste from discarded leftovers.

This depends on where you live.

• For the United States, there is a carbon footprint calculator created by The Nature Conservancy.
• For the UK, there is carbon footprint calculator created by the WWF.
• The Global Footprint Network has created another carbon footprint calculator.

Eliminating meat from your diet significantly reduces CO₂ emissions. However, butter and cheese cause relatively high CO₂ emissions, higher than, for example, chicken meat (source). So if you eat a lot of cheese, the carbon footprint of your diet will not necessarily be smaller than that of a meat-based diet.

Overall, however, it is much easier to be climate-friendly with a vegetarian diet than it is for people who regularly eat meat.

A vegan lifestyle has the smallest carbon footprint (source).

This is actually very intuitive: if you eat meat, the animals naturally need food that has to be grown especially for them. If you eat a vegan diet, this intermediate step of CO₂ emissions from animal production is eliminated. A large part of the CO₂ emissions from our food comes from animal agriculture and the destruction of forests for agriculture.

Whether you "have to" eat vegan is another question. I don't live vegan myself.

Yes, but it depends on whether a food is out of season here or everywhere in the world (source).

If the food is currently out of season here, but can be grown seasonally in other countries, transportation does not make a big difference to the carbon footprint: on average, only 6% of emissions are due to transportation (source). However, if the food is not available anywhere seasonally, the CO₂ emissions are significantly higher because it usually requires more energy to produce: The carbon footprint of strawberries, for example, is 11 times higher if they are grown in a greenhouse in winter rather than seasonally outdoors (source).

For example, it may be better for the climate to buy free-range tomatoes from Spain than tomatoes grown in a greenhouse in the United Kingdom.

Not really.

Transportation typically accounts for less than 10% of the carbon footprint of our food. Especially for food that is itself a major source of CO₂ emissions, transportation plays a minor role: For beef, transportation accounts for only 0.5% of emissions, even when transport between farms, slaughterhouses and retail outlets is included (source). For a more climate-friendly diet, it would be more important to avoid beef as much as possible, whether it comes from local farmers or is imported from Argentina.

A small exception is food that you know has definitely been transported by air: For example, if you compare the carbon footprint of pineapple that was flown instead of shipped, it is 25 times higher if it was flown and suddenly at the same level as beef - even if you include all the emissions for the production of the pineapple (source). However, whether your food is grown locally or transported to you by ship or truck has little impact on the total emissions.

Unfortunately, it is hard to say.

Organic food production uses less fertilizer, which is better for the carbon footprint. On the other hand, yields are often lower, so organic farming requires more land overall. There are also studies that suggest that overall CO₂ emissions would be higher with fully organic farming than they are today (source). This is the case with beef, for example: animals raised to organic standards live slightly longer on average and have a lower carcass weight - while this is good for the cattle, it also means that organic farming produces more CO₂ to produce the same amount of beef.

Overall, what you eat (no/less meat) is more important for your carbon footprint, not necessarily how it was produced.

This is rather unimportant for the CO₂ footprint.

On average, packaging is responsible for around 5% of the carbon footprint of food (source). There are upward spikes, especially for products where packaging can hardly be avoided (e.g. wine) or for foods with rather low emissions anyway (e.g. nuts).

Overall, it is much more important to avoid food being thrown away - both during production and trade and after purchase. Packaging also helps to protect food from damage and keep it in a condition in which we can eat it for longer. So if you buy food without packaging, remember to use it up before it goes bad.