Corn is the number one commodity grown by U.S. farmers. In fact, America is the largest producer and consumer of corn worldwide, dubbed as a corn global superpower. This sweet-tasting vegetable is also highly versatile, used in a variety of foods from popcorn and tortillas to high-fructose corn syrup, which is found in various items like soda and baked goods. Corn is even utilized in some of the most unexpected places, like envelopes, batteries, and toothpaste! Yet, much less is shared about the environmental impact, and especially the carbon emissions of corn. So we had to ask: What is the carbon footprint of corn?

Corn has a carbon footprint of 0.27 kg (0.60 lbs) of CO₂e per pound of produce, which is below average for vegetables. It is a land and water-intensive crop, which increases the carbon footprint. Over half of the carbon emissions are created during the harvesting and processing stages. 

In this article, we’ll walk you through the overall carbon emissions of the life-cycle of corn. From growing and packaging, to transportation and end-of-life practices, you will learn how this vegetable affects the planet and discover some ways to reduce and offset the footprint. 

Here’s How We Assessed the Carbon Footprint of Corn

The carbon footprint is one of the ways we measure the effects of our human-induced global climate change. It primarily focuses on the greenhouse gas (GHG) emissions associated with consumption, but also includes other emissions such as methane (CH₄), nitrous oxide, and chlorofluorocarbons, and is generally expressed in carbon dioxide equivalents (CO₂e).

“Carbon footprint: the amount of greenhouse gases and specifically carbon dioxide emitted by something (such as a person’s activities or a product’s manufacture and transport) during a given period”

Merriam Webster

Basically, it is the amount of carbon emitted by you as an individual or an organization providing you with goods and services – including corn:

• This includes GHG emissions from producing the products that we use and foods that we eat (e.g., power plants, factories or farms, and landfills)
• GHG emissions from fuel that we burn directly or indirectly (e.g., logistics and transportation, cooling or heating facilities),
• as well as the GHG emissions attributed to how we consume these products and foods.

To understand the carbon footprint of corn, we must assess its life-cycle and each stage’s sustainability. This life-cycle assessment (LCA) is a method to evaluate the environmental impacts of products and materials.

Here’s the Overall Carbon Footprint of Corn

The overall carbon footprint of corn is 0.27 kg (0.60 lbs) of CO₂e per pound of produce, which is fairly average for crops. Corn has the same carbon footprint as broccoli, cauliflower, kale and celery. It has a lower carbon footprint than other salad vegetables such as salad mix, tomato, cucumber, and bell pepper. 

With corn consumption so widespread, it is important to know the carbon footprint associated with this vegetable. Then, you can make sustainable choices when it comes to your food.

So, let’s have a look at each stage of the LCA of corn!

These four stages can be broken down in more detail to understand the factors which impact the carbon footprint of corn.

What Is the Carbon Footprint of Growing Corn

The carbon footprint of growing corn is 0.05 kg (0.1 lbs) of CO₂e per pound of produce, which makes up 23.80% of the overall carbon footprint of corn. As the most produced crop in the US, this intensive farming produces a great deal of carbon emissions. The land and water usage needed to grow corn increases the carbon footprint.

While growing corn does indeed produce carbon emissions, especially on such a large scale, it is also an effective carbon sink. A study by South Dakota State University found that “since 1985, the cropland acres in South Dakota alone have sequestered as much carbon as emitted by 17.8 billion gallons of gasoline.” 

Which factors impact the carbon footprint of growing corn?

• How do corn grow: Corn is a grain which grows in sheaves above ground. It thrives when planted in short rows, in a square pattern to allow for cross-pollination. Corn is also possible to grow vertically and hydroponically. A shift towards vertical farming would reduce the carbon footprint of corn. 
• What is the growth duration of corn: Corn can usually be harvested 60-140 days after seeding. In general, fewer resources have to be used on crops with short growth durations. Corn has a far shorter growth duration than more carbon intensive crops, like asparagus, but a much longer process than vegetables like lettuce and spinach.
• What is the land usage of corn: Corn uses more land than any other crop grown in the US, a massive 97 million acres in total. This is about the same size as the state of California. This has a detrimental impact on the carbon footprint of corn. 
• What is the water usage of corn: A study by agricultural engineer Tom Trout found that around 600,000 gallons of water were needed for 1 acre of corn plants, which produces just 200 bushels of corn. This makes corn quite water intensive, and increases the carbon footprint.
• What is the pesticide and fertilizer usage of corn: The Environmental Working Group found sweetcorn to be the second ‘cleanest’ crop. This means that in a list of 46 studied crops, corn contained the second least amount of pesticides. Pesticides increase the carbon footprint of a crop, since pesticides produce carbon emissions through manufacturing, transportation, and application to crops. However the low amount of pesticides found in corn may be due to the prevalence of genetically modified corn, which is bred to repel insects. GMO crops are the subject of many ethical debates, but they could help reduce carbon emissions.

In short, the water and land needed to grow corn increases the carbon emissions of this crop. With such an extensive use of corn in the US, the intensive growing of this crop has a large impact on the environment. 

What Is the Carbon Footprint of Harvesting, Processing, and Packaging Corn

The carbon footprint of harvesting, processing, and packaging corn is <0.18 kg (<0.4 lbs) of CO₂e per pound of produce, which makes up 58.62% of the overall carbon footprint of corn. This large fraction is due to the prevalence of processing and use of carbon-intensive combine harvesters when producing corn.

Only 1% of corn grown in the US is sweetcorn. The other 99% is primarily used for ethanol, high-fructose corn syrup, and animal feed. The industrial processing and harvesting of corn has a large impact on the carbon footprint of this crop. 

Which factors impact the carbon footprint of harvesting, processing, and packaging corn?

• How is corn harvested: Corn for the fresh market is often harvested by hand, but corn for the processed market is usually harvested by combine harvesters. Unfortunately, combine harvesters are thought to be damaging up to a fifth of the global agricultural land. Also, they have negative impacts on soil health and release a lot of carbon emissions, increasing the carbon footprint of corn. Only 1% of corn in the US is sweetcorn, the rest is used largely for animal feed. This means that hand-harvesting is rare. 
• How is corn processed: There are many different processing techniques, including grinding cornflour, canning, alkali processing, pre-cooking, and fermentation. This level of processing has a large impact on the carbon footprint of corn, due to the machines and processing plants needed, which require vast amounts of energy and release carbon emissions.
• How is corn packaged: Sweetcorn is sometimes sold loose, but also can be purchased in vacuum-packed plastic or cans. Unshucked corn is more likely to be sold loose, so this sort of corn has a lower carbon footprint. A corn based resin called Polylactic Acid (PLA) is being developed into a new alternative to traditional plastic packaging. It is renewable and compostable, meaning that corn could reduce the carbon footprint of plastic usage. 

In short, unpackaged and unprocessed corn has a far smaller carbon footprint than corn which has been processed and packaged in plastic. Purchasing fresh corn can help reduce your personal carbon footprint. 

What Is the Carbon Footprint of Transporting of Corn

The carbon footprint of transporting corn is 0.05 kg (0.1 lbs) of CO₂e per pound of produce, which makes up 17.58% of the overall carbon footprint of corn. The US is the number one worldwide producer of corn. However, most of this produce is not grown for human consumption. Corn for consumption in the US is commonly imported from Mexico which increases the food miles and the carbon footprint of this vegetable. 

Try and opt for locally grown corn where possible, to reduce the carbon footprint of this vegetable. 

Which factors impact the carbon footprint of transporting corn?

• Where is corn grown: Corn production in the US mainly occurs in Midwestern states, a region between Ohio and Nebraska known as the ‘Corn Belt’. About a third of US-grown corn grows in Illinois and Iowa. However, the majority of this corn is not grown for human consumption. The US actually imports corn from Mexico to consume. Because of this, the carbon footprint of corn is increased due to the food miles and carbon-intensive methods of transportation. 
• How is corn transported: Like the majority of fresh produce, corn is transported in refrigerated vehicles. These vehicles can emit up to 29 times more potentially carcinogenic particulate matter and six times more nitrogen oxides than far larger, modern diesel truck engines. If corn is purchased from local farms, the carbon footprint is decreased.

In short, buying locally grown corn reduces the carbon footprint. A movement towards corn-based packaging, as opposed to plastic, will reduce carbon emissions, and make corn, as well as food packaging in general, more sustainable. 

What Is the Carbon Footprint of the End-of-Life of Corn

The carbon footprint of the end-of-life of corn is largely impacted by the amount of food wasted. Corn makes up 2.9% of all avoidable vegetable waste, with 50,800 tons wasted every year. Moreover, the plastic packaging is bad for the environment, but lengthens the shelf-life, leading to less food waste.

Fresh corn can degrade very quickly, not usually lasting more than 5-7 days in the refrigerator. This short shelf life can lead to more food waste. Corn is compostable, but often ends up in landfill. In addition, the packaging is usually recyclable, but can also end up in landfill if not disposed of properly.

Which factors impact the carbon footprint of the end-of-life of corn?

• How is corn disposed of: 50,800 tons of avoidable corn waste is discarded every year. It is compostable, however, food waste in landfill is a big problem for the environment. 16% of all food is wasted on farms, largely for aesthetic reasons. The resources used to grow these crops just to discard them are enormous, and negatively impact the carbon footprint of this crop.
• How is the packaging of corn disposed of: Plastic packaging can increase the carbon footprint of a crop, due to the carbon-intensive resources needed to make the plastic. However, many of the polyethylene bags used for packaging are recyclable, as long as the polyethylene is not bonded with other plastics. This is because polyethylene is generally only recycled to make like-for-like products. Still, it is much more sustainable to buy loose produce. A lot of plastic that we recycle ends up on the other side of the world, causing a threat to developing countries. So, it is not as good for the environment as we may imagine. When corn is sold in plastic packaging, this increases the carbon footprint. 

In short, corn could be wasted due to a short shelf-life. This crop is often packaged in plastic, increasing the carbon footprint. To reduce waste, be conscious of not letting any food go bad, and recycling any plastic waste. 

How Does the Carbon Footprint of Corn Compare to Other Types of Food

Corn has quite a low carbon footprint compared to other vegetables. As well as this, vegetables tend to produce far fewer carbon emissions than other types of food. 

Let’s see how corn compares with other vegetables.

How Does the Carbon Footprint of Corn Compare to Other Types of Vegetables

In comparison to other vegetables, the carbon footprint of corn is just below average. For example, cucumbers produce over three times the carbon emissions of corn. However, in comparison to very low-carbon vegetables like cabbage, corn produces nearly four times as many carbon emissions. This is because salad vegetables tend to need more resources to grow, making their carbon footprint higher than root vegetables.

So, corn has a low average carbon footprint in comparison with other vegetables. But how does it compare to other types of food?

How Does the Carbon Footprint of Corn Compare to Other Types of Food in General

Corn is one of the most sustainable options in comparison to other types of food. It produces nearly 96 times less greenhouse gas emissions than beef. 

When it comes to greenhouse gas emissions (GHG), foods are often compared in terms of emissions per 1,000 kilocalories (as opposed to their weight in lbs or kg).

Additionally, since corn is low in calories, a far greater amount of produce is needed to equal 1,000 kilocalories.

• To eat 1,000 kilocalories, you would need to consume over 10 servings, or over 12 cobs, or 36.7 ounces.
• In comparison to beef you would only need 4.6 servings to eat 1,000 kilocalories, or 16 ounces.
• Comparatively, salad vegetables have an extremely high carbon footprint per kilocalorie, but are enormously less calorific than animal-based food.
• More calorific plant-based foods, such as pulses and nuts, have a miniscule carbon footprint in comparison to animal-based proteins. A single portion of beef has over double the calories of a portion of corn. 
• This means that per portion, you will be consuming fewer calories, and so the carbon footprint will not be as large as this graph suggests.

Even though the carbon emissions for corn is very low in comparison to other types of food, try to be mindful of the ways you can lessen your environmental impact when you purchase it.

How Can You Reduce and Offset Your Personal Carbon Footprint

All of the food you eat will have some form of carbon footprint, even when you buy foods with relatively average CO₂e, such as corn. However, there are ways to offset and reduce your personal carbon footprint. 

There are a few easy techniques to buy more eco-friendly corn, and you can also find ways to offset the carbon footprint after your purchase. 

How Can You Reduce Your Carbon Footprint When Shopping for Corn

When shopping for corn, consider these ways to lessen your impact on the environment. 

1. Shop locally and seasonally: Corn is usually in season from late summer to early fall, depending on the state where it is grown. Buying from local farms reduces the carbon emissions produced and makes it a much more sustainable choice.
2. Choose organic: Organic corn produces a much lower carbon footprint than non-organic vegetables, due to the lack of pesticide production, distribution, and the overall higher health of soil for crops, insects, and animals.
3. Avoid waste: Corn often can end up going bad in the refrigerator. Avoid this by storing your corn correctly, and consuming it quickly. It is recommended to eat corn on the day of purchase. It has a shelf life of about a week, but reduces in sweetness the longer it is left. It is possible to freeze corn to extend shelf life. 

Taking these actions are a great way to lessen your own carbon footprint, but there are also ways to offset the impact of consuming corn as well.

How Can You Offset Your Personal Carbon Footprint

Carbon offsets are reductions in carbon emissions that are used to compensate for carbon emissions occurring elsewhere – for example for the carbon emissions that are associated with corn. They are measured in tons of CO₂ equivalents and are bought and sold through international brokers, online retailers, and trading platforms on what is known as the global carbon offset market. 

“Carbon Offset: a way for a company or person to reduce the level of carbon dioxide for which they are responsible by paying money to a company that works to reduce the total amount produced in the world, for example by planting trees”

Oxford Dictionary

In terms of corn – and indeed all food types – there will always be a carbon footprint, because of the resources it takes to get your food from farms to the place where you’ll eventually eat them. And while there are ways to reduce your carbon footprint when shopping for corn, carbon offsets would be a way to reduce your CO₂e emissions all the way down to net zero (or even to become climate positive).

However, when you purchase carbon offsets, it’s important that they actually make a difference in offsetting (aka reducing) total carbon emissions. To achieve that, the following are key criteria:

• Carbon offset projects have to be effective (different projects have different effectiveness rates)
• Carbon offset projects have to be additional
• Carbon offset projects have to be permanent
• The claims from carbon offset projects have to be verifiable

To find the best carbon offsets for you personally, check out our full guide on the best carbon offsets for individuals, where you’ll also learn more about how these carbon offset projects work, what their respective offsetting costs are, and what your best way would be to offset your own carbon emissions.

Final Thoughts

Corn has a very low carbon footprint in comparison to other food, and a slightly below average carbon footprint when compared with other vegetables. Try to reduce your carbon footprint further by eating organic, reducing food waste, and purchasing local, seasonal produce. As hydroponic farming becomes a more viable source for the production of corn, the growing process will have a lower carbon footprint, and become more localized. When you do enjoy corn, think about whether you can offset the carbon emissions created, to make this healthy snack a more sustainable option! 

Stay impactful,

Sources

• My Dad’s Sweet Corn: 27 Items You Didn’t Know Were Made from Corn
• Successful Farming: Corn Growing 101
• CNBC: How the U.S. became a global corn superpower
• The Washington Post: How corn made its way into just about everything we eat
• Britannica: Carbon footprint
• Science Direct: Life-cycle assessment (LCA)
• MIT SMR: Strategic Sustainability Uses of Life-Cycle Analysis
• Carbon Cloud: Super Sweet Corn
• Impactful Ninja: What Is the Carbon Footprint of Broccoli
• Impactful Ninja: What Is the Carbon Footprint of Cauliflower
• Impactful Ninja: What Is the Carbon Footprint of Kale
• Impactful Ninja: What Is the Carbon Footprint of Celery
• Impactful Ninja: What Is the Carbon Footprint of Salad Mix
• Impactful Ninja: What Is the Carbon Footprint of Tomatoes
• Impactful Ninja: What Is the Carbon Footprint of Cucumber
• Impactful Ninja: What Is the Carbon Footprint of Bell Peppers 
• FoodPrint: The Rise of Industrial Corn Production
• WRAP: The Food We Waste
• Farm Progress: Corn As A Carbon Sink
• Agrotonomy: Growing corn on a Tower Garden
• Intelligent Growth Solutions: Farming and its environmental impacts: is Vertical Farming the solution?
• Impactful Ninja: What Is the Carbon Footprint of Asparagus 
• Impactful Ninja: What Is the Carbon Footprint of Lettuce
• Impactful Ninja: What Is the Carbon Footprint of Spinach
• Scientific American: It’s Time to Rethink America’s Corn System
• United States Department of Agriculture: Growing Crops and Saving Water in the West
• Environmental Working Group: Full List
• Harvard University: GMOs and Pesticides: Helpful or Harmful?
• Healthline: GMOs: Pros and Cons, Backed by Evidence
• National Library of Medicine: Genetically modified crops support climate change mitigation
• Iowa Corn: Corn Facts
• Nebraska Corn Board: What Happens to Corn After It Is Harvested
• BBC News: Farm machinery exacting heavy toll on soil – study
• Farms Wise: Are Tractors Bad for the Environment?
• Miller Refereed: Corn Production, Consumption and Corn Processing Technologies 
• KBT Food Pack: Ideas of sweet corn cobs packaging and storage
• Smithsonian Magazine: Corn Plastic to the Rescue
• USDA: Economic Research Service: Most corn production in U.S. and Mexico is geographically concentrated
• USDA: Economic Research Service: Feed Grains Sector at a Glance
• The ACR Journal: Refrigerated vehicles contribute to thousands of deaths and costs across EU
• Cook Think: How Long Does Corn Last in The Fridge
• World Wildlife Fund: Fight climate change by preventing food waste
• World Wildlife Fund: What farmers found when they measured fresh produce left in the field
• Let’s Recycle: Supermarkets to take back plastic film in-store
• Sesotec: Recycling more packaging –potential for PE and PP
• Live Science: The Plastic We ‘Recycle’ Is Actually Horrible for the Environment
• Impactful Ninja: What Is the Carbon Footprint of Cabbage
• Impactful Ninja: What Is the Carbon Footprint of Carrots
• Impactful Ninja: What Is the Carbon Footprint of Mushrooms
• Impactful Ninja: What Is the Carbon Footprint of Onions
• Impactful Ninja: What Is the Carbon Footprint of Potatoes
• Our World in Data: Greenhouse Gas Emissions per 1000 kilocalories
• Healthline: Corn 101: Nutrition Facts and Health Benefits
• Healthline: Beef 101: Nutrition Facts and Health Effects
• Machine Finder: A Visual Look at Typical United States Corn Harvest Dates
• Columbia Climate School: Is Organic Food Really Better for the Environment?
• Masterclass: How to Store Corn on the Cob: 3 Tips for Storing Corn
• Impactful Ninja: 12 Best Carbon Offsets for Individuals