Green
The Carbon Footprint of the Food Supply Chain
Which Foods Have the Greatest Environmental Impact?
The quantity of greenhouse gases (GHGs) generated by our food can vary considerably across the global food supply chain.
In fact, the difference between specific food types can vary by orders of magnitude, meaning what we eat could be a significant factor impacting GHG emissions on the environment.
Today’s modified chart from Our World in Data relies on data from the largest meta-analysis of food systems in history. The study, published in Science was led by Joseph Poore and Thomas Nemecek to highlight the carbon footprint across different food types across the world.
The Foods With the Highest Carbon Footprint
Worldwide, there are approximately 13.7 billion metric tons of carbon dioxide equivalents (CO2e) emitted through the food supply chain per year.
Across a database extending through 119 countries and 38,000 commercial farms, the study found that, unsurprisingly, beef and other animal products have an outsize effect on emissions.
For example, one kilogram (kg) of beef results in 60 kg of GHG emissions—nearly 2.5x the closest food type, lamb and mutton. In contrast, the same weight of apples produce less than one kilogram of GHG emissions.
Food Type | GHG Emissions per 1 kg Produced |
---|---|
Beef (beef herd) | 60 kgCO2e |
Lamb & Mutton | 24 kgCO2e |
Cheese | 21 kgCO2e |
Beef (dairy herd) | 21 kgCO2e |
Chocolate | 19 kgCO2e |
Coffee | 17 kgCO2e |
Prawns (farmed) | 12 kgCO2e |
Palm Oil | 8 kgCO2e |
Pig Meat | 7 kgCO2e |
Poultry Meat | 6 kgCO2e |
Olive Oil | 6 kgCO2e |
Fish (farmed) | 5 kgCO2e |
Eggs | 4.5 kgCO2e |
Rice | 4 kgCO2e |
Fish (wild catch) | 3 kgCO2e |
Milk | 3 kgCO2e |
Cane Sugar | 3 kgCO2e |
Groundnuts | 2.5 kgCO2e |
Wheat & Rye | 1.4 kgCO2e |
Tomatoes | 1.4 kgCO2e |
Maize (Corn) | 1.0 kgCO2e |
Cassava | 1.0 kgCO2e |
Soymilk | 0.9 kgCO2e |
Peas | 0.9 kgCO2e |
Bananas | 0.7 kgCO2e |
Root Vegetables | 0.4 kgCO2e |
Apples | 0.4 kgCO2e |
Citrus Fruits | 0.3 kgCO2e |
Nuts | 0.3 kgCO2e |
When it comes to plant-based foods, chocolate is among the highest GHG emitters. One kilogram of chocolate produces 19 kg of GHGs. On average, emissions from plant-based foods are 10 to 50 times lower than animal-based types.
Bottom line, it is clear that the spectrum of emissions differs significantly across each food type.
Food Supply Chain Stages
The food supply chain is complex and nuanced as it moves across each stage of the cycle.
Although the steps behind the supply chain for individual foods can vary considerably, each typically has seven stages:
- Land Use Change
- Farm
- Animal Feed
- Processing
- Transport
- Retail
- Packaging
Across all foods, the land use and farm stages of the supply chain account for 80% of GHG emissions. In beef production, for example, there are three key contributing factors to the carbon footprint at these stages: animal feed, land conversion, and methane production from cows. In the U.S., beef production accounts for 40% of total livestock-related land use domestically.
On the other end of the spectrum is transportation. This stage of the supply chain makes up 10% of total GHG emissions on average. When it comes to beef, the proportion of GHGs that transportation emits is even smaller, at just 0.5% of total emissions.
Contrary to popular belief, sourcing food locally may not help GHG emissions in a very significant way, especially in the case of foods with a large carbon footprint.
The Rise of Plant-Based Alternatives
Amid a growing market share of plant-based alternatives in markets around the world, the future of the food supply chain could undergo a significant transition.
For investors, this shift is already evident. Beyond Meat, a leading provider of meat substitutes, was one of the best performing stocks of 2019—gaining 202% after its IPO in May 2019.
As rising awareness about the environment becomes more prevalent, is it possible that growing meat consumption could be a thing of the past?
Environment
The Most Polluted Cities in the U.S.
What are the most polluted cities in the U.S. according to data from the American Lung Association’s 2024 State of the Air Report?
The Most Polluted U.S. Cities in 2024
According to the World Health Organization, air pollution is responsible for 7 million deaths annually, and could cost the global economy between $18–25 trillion by 2060 in annual welfare costs, or roughly 4–6% of world GDP.
And with predictions that 7 in 10 people will make their homes in urban centers by mid-century, cities are fast becoming one of the frontlines in the global effort to clear the air.
In this visualization, we use 2024 data from the State of the Air report from the American Lung Association to show the most polluted cities in the United States.
What is Air Pollution?
Air pollution is a complex mixture of gases, particles, and liquid droplets and can have a variety of sources, including wildfires and cookstoves in rural areas, and road dust and diesel exhaust in cities.
There are a few kinds of air pollution that are especially bad for human health, including ozone and carbon monoxide, but here we’re concerned with fine particulate matter that is smaller than 2.5 microns, or PM2.5 for short.
The reason for the focus is because at that small size, particulate matter can penetrate the bloodstream and cause all manner of havoc, including cardiovascular disease, lung cancer, and chronic pulmonary disease.
The American Lung Association has set an annual average guideline of 9 µg/m³ for PM2.5, however, the World Health Organization has set a much more stringent limit of 5 µg/m³.
The 21 Worst Polluted Cities in the U.S.
Here are the top 21 most polluted cities in the U.S., according to their annual average PM2.5 concentrations:
Rank | City, State | Annual average concentration, 2020-2022 (µg/m3) |
---|---|---|
1 | Bakersfield, CA | 18.8 |
2 | Visalia, CA | 18.4 |
3 | Fresno, CA | 17.5 |
4 | Eugene, OR | 14.7 |
5 | Bay Area, CA | 14.3 |
6 | Los Angeles, CA | 14.0 |
7 | Sacramento, CA | 13.8 |
8 | Medford, OR | 13.5 |
9 | Pheonix, AZ | 12.4 |
10 | Fairbanks, AK | 12.2 |
11 | Indianapolis, IN | 11.9 |
12 | Yakima, WA | 11.8 |
13 | Detroit, MI | 11.7 |
T14 | Chico, CA | 11.6 |
T14 | Spokane, WA | 11.6 |
15 | Houston, TX | 11.4 |
16 | El Centro, CA | 11.1 |
17 | Reno, NV | 11.0 |
18 | Pittsburgh, PA | 10.9 |
T19 | Kansas City, KS | 10.8 |
T19 | Las Vegas, NV | 10.8 |
Note: The American Lung Association uses Core Based Statistical Areas in its city and county rankings, which have been shortened here to the area’s principal city, or metro area in the case of the Bay Area, CA.
Six of the top seven cities are in California, and four in the state’s Central Valley, a 450-mile flat valley that runs parallel to the Pacific coast, and bordered by the Coast and Sierra Nevada mountain ranges. As a result, when pollution from the big population centers on the coast is carried inland by the wind—cities #5 and #6 on the list—it tends to get trapped in the valley.
Bakersfield (#1), Visalia (#2), and Fresno (#3) are located at the drier and hotter southern end of the valley, which is worse for air quality. The top three local sources of PM2.5 emissions in 2023 were farms (20%), forest management / agricultural waste burning (20%), and road dust (14%).
Benefit to Economy
While the health impacts are generally well understood, less well known are the economic impacts.
Low air quality negatively affects worker productivity, increases absenteeism, and adds both direct and indirect health care costs. But the flip side of that equation is that improving air quality has measurable impacts to the wider economy. The EPA published a study that calculated the economic benefits of each metric ton of particulate matter that didn’t end up in the atmosphere, broken down by sector.
Sector | Benefits per metric ton |
---|---|
Residential Woodstoves | $429,220 |
Refineries | $333,938 |
Industrial Boilers | $174,229 |
Oil and Natural Gas Transmission | $125,227 |
Electricity Generating Units | $124,319 |
Oil and Natural Gas | $88,838 |
At the same time, the EPA recently updated a cost-benefit analysis of the Clean Air Act, the main piece of federal legislation governing air quality, and found that between 1990 and 2020 it cost the economy roughly $65 billion, but also provided $2 trillion in benefits.
Benefit to Business
But that’s at the macroeconomic level, so what about for individual businesses?
For one, employees like to breathe clean air and will choose to work somewhere else, given a choice. A 2022 Deloitte case study revealed that nearly 70% of highly-skilled workers said air quality was a significant factor in choosing which city to live and work in.
At the same time, air quality can impact employer-sponsored health care premiums, by reducing the overall health of the risk pool. And since insurance premiums averaged $7,590 per year in 2022 for a single employee, and rose to $21,931 for a family, that can add up fast.
Consumers are also putting their purchase decisions through a green lens, while ESG, triple-bottom-line, and impact investing are putting the environment front and center for many investors.
And if the carrot isn’t enough for some businesses, there is the stick. The EPA recently gave vehicle engine manufacturer Cummins nearly two billion reasons to help improve air quality, in a settlement the agency is calling “the largest civil penalty in the history of the Clean Air Act and the second largest environmental penalty ever.”
Learn how the National Public Utilities Council is working toward the future of sustainable electricity.
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