Food CO2 emissions: the sum of all the greenhouse gas emissions (GHGEs) associated with food production, processing, transporting, and retailing.
“How much CO2 emissions come from …?”
[Insert food item above.]
This is the question that I and many others first asking when trying to reduce our carbon footprint through food. To build a diet that combats climate change, I knew I needed a list of food CO2 emissions. After researching for days and not finding a resource that showed me exactly what I was looking for, I set out to create it myself.
What’s included in the Food & CO2 ebook?
I researched the CO2 emissions of different foods and gathered all that information into this ebook. There, you can find the average CO2 emissions for many popular food items and the food groups.
Use this book as a guide to making smarter food choices that will lower your overall carbon footprint. However, don’t get too caught up in the numbers. As I explain later in this article, different studies show varying results with different scopes and sample sizes. The data in this ebook reflects the most recent numbers from reputable sources, representing mostly North American and global studies.
Here are chapters covered in the ebook:
- Greenhouse Gas Emissions by Food Product
- Carbon Emissions by Food Group
- CO2 Emissions of Meat Alternatives
- How Much CO2 Emissions Come from Dairy?
- Which Milk Should I Choose?
- Fruits & Vegetables with the Smallest Carbon Footprint
- The Worst Produce to Eat Out of Season
- Coffee, Chocolate, Alcohol, and Their Environmental Impacts
Ranking food greenhouse gas emissions (GHGEs) by serving
There are plenty of statistics around greenhouse gas emissions by food groups. But which statistics is correct? How does that translate to the CO2 emissions on the plate?
The chart above shows how much greenhouse gas emissions (GHGEs) are produced by 1 serving of each food product. The serving size for each food product on the list is based on USDA dietary recommendations.
These numbers were calculated by multiplying the average CO2 emissions/1 kg by kg/serving size according to the USDA recommended dietary intake.
Can I compare CO2 emissions by calories?
Another way to represent CO2 emissions in food is to compare the carbon intensity of foods by by calorie (kcal).
The figures and stats below show the amount of CO2 emissions (g) per calorie consumed (kcal). The total emissions account for food eaten, consumer waste, and supply losses.
While red meat (like beef and lamb) still stand out as the most carbon-intense food group, these numbers can be misleading. Oils, sugars, and grains are high caloric foods but experience relatively low waste in production and consumption. On the other hand, edible fruit and vegetables are more often lost via consumer waste and supply chain.
Rather than using these stats as a measure for what foods a person should or should not consume to lower their carbon footprint, this graph shows where agricultural practices can be improved and food waste reduced.
What impacts carbon emissions of food?
Of the greenhouse gases, carbon dioxide is the biggest contributor to climate change. Methane and nitrous oxide are second and third, both influencing the overall carbon footprint of food.
The methane release by cows accounts for much of beef’s high GHGE – it is also 8x more harmful to the environment that carbon dioxide. Food and its production can also produce methane from various agricultural activities, waste management, energy use and burning biomass (aka, burning crop stubble, vegetation, or forest). Fertilizer is the most common contributor of nitrous oxide.
When researchers calculate the GHGEs of different foods, they consider several sources of CO2 emissions. These can be broken down into two different categories: Pre-market CO2 emissions, and post-market CO2 emissions.
Pre-market CO2 emissions:
- Agricultural practices: How much fertilizer is used? How much water is required, How much land is required? How much GHGEs come from the sourcing of the food (i.e. cow farts = methane)?
- Processing: What carbon costs are associated with food processing, packaging, and other practices required to get the raw produce or meat to its market-ready form?
- Transportation: How far does the food travels (“food miles”) to get to consumers, and what are the carbon costs associated with that type of transportation?
Post-market CO2 emissions:
- Food storage: How do households, restaurants, and markets store food until it’s ready to be consumed or cooked?
- Cooking method: How is the food cooked (if at all) before it is eaten?
- Food waste: How much edible food is lost in the preparation process or thrown away without being eaten?
For the ebook I created, I chose to focus only on pre-market CO2 emissions. Since a large part of post-market CO2 emissions are behavior-based, these statistics are harder to find and depend upon the scope of the study.
Can we assign a GHGE to individual food items?
Yes… and no. No comprehensive list of food CO2 emissions existed because no study exists that covers the depth of GHGEs around food for a wide enough scope.
So many factors go into the greenhouse gas emissions from food, and there is not enough research done on this topic to have a decisive carbon footprint for each food. Each country would have unique CO2 emissions for produce due to its food culture, agricultural practices, and which foods are imported versus grown locally. There’s variance even among the same strain of the same produce.
The ebook I created reflects these variances. The data comes from several studies around the world, so you may see some overlap or contradictory numbers from other studies. However, the overall emphasis on which food groups are better or worse for the environment will likely be the same.
Measuring the CO2 emissions of food is complex. That’s why a deep and broad study is needed to build a comprehensive guide that gives accurate data for each food item. Until more research exists on this topic, the findings cited in the ebook are the closest to the average CO2 emissions for different foods.
Why are GHGEs around food important?
Food – how it is produced, transported, and consumed – can have a big impact on the environment and climate change.
Global livestock ranks as a top contributor to global greenhouse gas emissions (GHGEs) at approximately 7.1 gigatonnes of CO2 per year. That’s 7,100,000,000 tons of CO2 each year, representing 14.5% of all man-made GHGEs, according to the FOA.
In their Emissions Gap Report 2017, the United Nations called for “an urgent need” for action to lower GHGEs in order to keep the Park Agreement goals achievable. While the United Nations and some countries have introduced plans to combat climate change, CO2 emissions are still rising. See the graph below from the report to compare the different sectors’ GHGEs and their potential to reduce emissions.
The agricultural sector is unique to the top 5 contributors of global emissions because the impact an individual can make is more tangible. People can control the food choices they make, where they source it, and how effectively they prepare and eat it.
Key takeaways to reduce food CO2 emissions
Based on the research cited in the study, there are definite ways to lower one’s CO2 emissions by making smarter, sustainable food choices.
- Reducing the consumption of meat and dairy: Even just reducing the amount of red meat consumed, a person can significantly lower their carbon footprint. While a vegan diet (no meat or dairy products) is the most sustainable diet, vegetarian diets and moderate meat consumption can still reduce CO2 emissions.
- Eating locally-sourced foods: As is the case for asparagus, food miles can play a big role is food CO2 emissions. Take the advice of Michael Pollan and “shake the hand that feeds you” – buy produce from local markets, farmers, and vendors. In doing so, you are more likely to eat foods that are in season, too.
- Buying less processed foods: While sugars, snacks, and oils scored lowest on carbon emissions by calorie, processed foods are not off the hook. These food items have hidden CO2 emissions that are devastating forests, depleting the soil and land of nutrients and biodiversity, often sourced with high-carbon emitting agricultural practices, and consuming large quantities of water. To curb these effects, cut back on highly-processed foods and at-risk food products, including coffee and chocolate.
Whether you’re a foodie, environmentalist, or simply curious, I hope this article and ebook give you knowledge and inspiration for your next meal.
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