September 2020

Counting the climate cost of the food we eat

Every year in the UK, each person, on average, emits 5 - 10 tonnes of carbon dioxide (CO2) or the equivalent of other greenhouses gases such as methane and nitrous oxide. We need to reduce these emissions drastically if the UK is to meet its commitment to be carbon neutral by 2050.

When discussing the need to reduce emissions of greenhouse gases, we usually concentrate on electricity generation, household heating, and transport. But did you know that food accounts for about 20% of our emissions?

The main contributors to these emissions are:

  •        agriculture: methane from cattle; nitrous oxide from fertilizers added to crops
  •        food processing and transport
  •        packaging of food
  •        waste – over 30% of food is wasted in the UK, 16% in households.

Here are some examples of annual emissions of CO2 equivalent from daily food consumption.
Remember, 1000 kg = 1 tonne.

 Daily consumption
 Annual emissions
(kg CO2 equivalent)
 Daily consumption  Annual emissions
(kg CO2 equivalent)
 50 g breakfast cereal  30  100 g green salad  15
 150 ml milk  55  1 apple  20
 1 egg  100  1 banana  30
 2 slices of bread (100g)  30  1 tomato (40 g)  20

Compare these with eating meat:

Annual emissions
(kg CO2 equivalent)


Annual emissions
(kg CO2 equivalent)

 200 g British beef  250  200 g British lamb  150

If you eat a banana and an apple a day, this would be responsible for the emission of 50 kg of CO2 in a year.

Eating 200g of beef a week would result in 250 kg of CO2 in a year.

Transport is usually a small contributor, except when the food is air-freighted – don’t eat asparagus from Peru.
Avoid food produced in a hothouse – tomatoes from Spain are better than from the UK, except in the summer.
Local and seasonal is best when possible. Even better, grow your own!

We have to eat, but it is important to assess the climate impact of what we do eat – can we reduce that impact in a sensible way? Eating meat, and especially beef, leads to high emissions. You don’t have to be vegetarian but you need to appreciate the impact of eating meat: moderation and awareness are key. Also, don’t waste food.

We’ve concentrated here solely on greenhouse gas emissions. There are many other issues with food, such as the way it is produced. Chicken has lower carbon emissions than beef or lamb, but is it free range? (See for critical comments on eating chicken). Are the bananas Fairtrade? And what about organic food? 


Why not calculate the total emissions from the food you eat yourself?  

You need to use the total emissions per kilogram of food (the emission factor (EF)) and then estimate how much you eat per year.

Good sources of information on EFs are the books by Mike Berners-Lee (How bad are bananas?  (an updated edition is due in September) and There is no Planet B.) He has also carried out an analysis on the Greenhouse gas footprint of Booths that can be found here ( (Appendix A is a table of emission factors and will allow you to make a start.) You will see that the EFs vary depending on the farming system used.

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