Roasted, fried, boiled, or mashed, sweet potatoes are one of the more versatile vegetables, which is why the popularity of this crop has skyrocketed by over 40% in the last two decades. The US started growing sweet potatoes during WWII, but they were slowly fading from the American cookbook, until the popularity of sweet potato fries. However, much less is shared about the environmental impact, and especially the carbon emissions of sweet potatoes. So we had to ask: What is the carbon footprint of sweet potatoes?

Sweet potatoes have a carbon footprint of 0.10 kg (0.22 lb) of CO₂e per pound of produce, which is very low for crops. Nearly 90% of the carbon footprint is produced in the growing stage of this crop. Sweet potatoes can be grown locally, with few resources, leading to a low carbon footprint.

In this article, we’ll walk you through the overall carbon emissions of the life-cycle of sweet potatoes. 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 Sweet Potatoes

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 sweet potatoes:

• 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 sweet potatoes, 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 Sweet Potatoes

The overall carbon footprint of sweet potatoes is 0.10 kg (0.22 lb) of CO₂e per pound of produce, which is very low for crops. Sweet potatoes produce less than half of the carbon emissions of lettuce, and ten times less carbon emissions than cucumber.

Sweet potatoes are an increasingly popular vegetable, so it is important to know the carbon footprint associated with this plant. 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 sweet potatoes!

These four stages can be broken down in more detail to understand why the carbon footprint of sweet potatoes is low in comparison to other vegetables.

What Is the Carbon Footprint of Growing Sweet Potatoes

The carbon footprint of growing sweet potatoes is 0.09 kg (0.19 lb) of CO₂e per pound of produce. This amounts to nearly 90% of the overall carbon footprint. The growing period of any crop tends to be resource-intensive, due to the land, water, and pesticide usage. Sweet potatoes are land-efficient, and are treated with very few pesticides so they have a relatively low growth carbon footprint. 

Sweet potatoes are grown from cuttings, and require warm conditions to grow. The resources required by this crop are why the growing period of sweet potatoes is the most carbon-intensive. Fewer resources needed in the agricultural process lead to a far smaller carbon footprint. 

Which factors impact the carbon footprint of growing sweet potatoes?

• How do sweet potatoes grow: Sweet potatoes are grown from vine cuttings, or ‘slips’, rather than from seeds. The roots of these cuttings then grow into the sweet potato. The root is the most commonly eaten part of this crop, but the flowers and leaves are edible too. Sweet potatoes are a tropical plant, and require warm soil, meaning that many are grown in energy-intensive greenhouses, which increases the carbon footprint.
• What is the growth duration of sweet potatoes: Sweet potatoes mature in around 85-120 days. This is an above-average growing time, similar to that of peppers. A longer than average growing time increases the carbon footprint, due to the extra resources needed.
• What is the land usage of sweet potatoes: Sweet potatoes can yield 10-15 tons per hectare, which is a relatively high yield. This means the carbon footprint is lower than low-yield vegetables, because less resources are needed to grow more crops.
• What is the water usage of sweet potatoes: Sweet potatoes are classed as a mildly drought-tolerant plant. Despite this, many farmers opt to use drip irrigation techniques to maximize the yield. Up to 95% of Californian sweet potato farmers use drip irrigation, which requires energy. This contributes to the carbon footprint of this plant
• What is the pesticide and fertilizer usage of sweet potatoes: The Environmental Working Group has found that sweet potatoes are one of the crops treated with the fewest pesticides. It scored 13th out of 46 tested crops, making it part of the ‘clean fifteen list’. Since pesticide usage produces carbon emissions through manufacturing, transportation, and application to crops. The fact that potatoes are treated with minimal pesticides has a positive impact on the environment.

In short, the growing process of any vegetable usually is the most carbon-intensive stage, and this is true with sweet potatoes. However, due to the low water, land, and pesticide use, sweet potatoes have a low carbon footprint. 

What Is the Carbon Footprint of Harvesting, Processing, and Packaging Sweet Potatoes

The carbon footprint of harvesting, processing, and packaging sweet potatoes is <0.05 kg (<0.1 lb) of CO₂e per pound of produce. This amounts to 11.48% of the overall carbon footprint of this crop. The use of plastic packaging, and processed sweet potato products like sweet potato fries, increase the overall carbon footprint.

Sweet potatoes are harvested by carbon-intensive machines, and are processed into many different dishes, such as fries, chips, rice, and mash. The resources needed for these processes contribute to the carbon emissions of sweet potatoes. 

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

• How are sweet potatoes harvested: Sweet potatoes are generally harvested by machine. This is more labor-efficient than hand-harvesting, however these tractors have negative impacts on soil health and release a lot of carbon emissions, increasing the carbon footprint of sweet potatoes. 
• How are sweet potatoes processed: Sweet potatoes are left to cure for 5-7 days in temperature- and humidity-controlled areas. They can then either be sold to the whole-market, or processed. Sweet potatoes are very versatile, and can be turned into a whole host of products, such as flour, dried chips, juice, bread, noodles, or candy. This processing requires a lot of electricity and resources, increasing the carbon footprint. However, these processed products could lead to less waste, due to extended shelf-life, which would decrease the carbon footprint of sweet potatoes. 
• How are sweet potatoes packaged: Sweet potatoes can either be transported loose in barrels, or crates, or packaged in hessian bags, poly-mesh, polyethylene bags, or kraft paper. These are generally quite eco-friendly materials, however poly-mesh, and polyethylene are plastics which increase the carbon footprint. Choosing plastic-free sweet potatoes is a more sustainable choice. 

In short, the processing and harvesting stages are relatively carbon-intensive. Buy packaging-free, whole sweet potatoes to lower the carbon footprint of this crop. 

What Is the Carbon Footprint of Transporting of Sweet Potatoes

The carbon footprint of transporting sweet potatoes needs to be researched more to find an exact figure of carbon emissions. Since the US is the world’s largest importer of this crop, the food miles of internationally grown crops will contribute significantly to the overall carbon footprint of sweet potatoes.

Sweet potatoes can grow in the United States, in states like North Carolina, California, and Mississippi. Processed sweet potatoes are often imported from across the world, so aim to buy local, fresh potatoes, as they have a much smaller carbon footprint. 

Which factors impact the carbon footprint of transporting sweet potatoes?

• Where are sweet potatoes grown: North Carolina grows the majority of the US’ sweet potatoes, producing 63.50%. California and Mississippi also grow a significant proportion. However, the US is also the world’s largest importer of sweet potato, and ships most of its produce from China, Honduras, and the Dominican Republic. Shipping across the world increases the carbon footprint, so aim to buy local produce.
• How are sweet potatoes transported: Sweet potatoes are transported either by road, rail, air, or ship. Like most fresh produce, they require constant refrigeration in the transportation process. Unfortunately, refrigerated 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 sweet potatoes are bought from local farms, the carbon footprint is decreased.

In short, locally grown sweet potatoes produce far fewer carbon emissions than imported sweet potatoes, so aim to find local farms. This will decrease your food miles, and make your sweet potato consumption less carbon-intensive.

What Is the Carbon Footprint of the End-of-Life of Sweet Potatoes

The carbon footprint of the end-of-life of sweet potatoes is largely impacted by the amount of food wasted. Unfortunately, globally around 45% of tubers are wasted a year. This increases the carbon footprint. Any packaging used is bad for the environment, but lengthens the shelf-life, leading to less food waste. This can be offset by proper storing methods, which can increase shelf-life without the need for plastic packaging. 

Sweet potatoes have a very long shelf-life, and can be stored for months in the right conditions. However, nearly half of all tubers are discarded. Be conscious of your consumption to reduce this waste. 

Which factors impact the carbon footprint of the end-of-life of sweet potatoes?

• How are sweet potatoes disposed of: 45% of tubers are discarded, meaning that there are over 350,000 tonnes of avoidable tuber waste a year. Sweet potatoes are completely compostable but often end up in landfill, which is a big problem for the environment. Sweet potatoes can actually last for months, but consumers are often put off by premature sprouting, caused by improper storage. Keep sweet potatoes in a paper or cardboard bag in a cool, dark pantry to increase their shelf-life and reduce the likelihood of waste. 
• How is the packaging of sweet potatoes disposed of: Plastic packaging can be difficult to recycle. 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. Since processed sweet potatoes are rarely sold loose, this increases the carbon footprint.

In short, there is a great deal of sweet potato waste, which increases the carbon footprint of this product. Be aware of reducing waste, and not buying too many sweet potatoes, that may go off before you have a chance to consume them. Aim to buy loose sweet potatoes to reduce plastic waste, or sweet potatoes packaged in recyclable materials.

How Does the Carbon Footprint of Sweet Potatoes Compare to Other Types of Food

Sweet potatoes have a very low carbon footprint compared to other vegetables. Additionally, vegetables tend to produce far fewer carbon emissions than other types of food, making sweet potatoes a highly sustainable snack choice!

Let’s see how sweet potatoes compare with other vegetables.

How Does the Carbon Footprint of Sweet Potatoes Compare to Other Types of Vegetables

In comparison to other vegetables, the carbon footprint of sweet potatoes is low. For example, cucumbers produce ten times the carbon emissions of sweet potatoes. Salad vegetables need more resources to grow, making their carbon footprint far higher than root vegetables.

So, sweet potatoes are one of the more sustainable vegetables, but how do they compare to other types of food?

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

Root vegetables have a very low carbon footprint in comparison to other types of food. Sweet potatoes produce around 88 times fewer 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 sweet potatoes are 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 11.1 servings, which is around 10 small sweet potatoes or 39 ounces.
• In comparison to beef you would only need 4.6 servings to eat 1,000 kilocalories, or 16 ounces.
• Comparatively, vegetables can have a 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 amounts to around two and a half portions of sweet potatoes, in terms of calories.
• 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 sweet potatoes are low in comparison to other types of food, try to be mindful of the ways you can lessen your environmental impact when you purchase them.

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 low CO₂e, such as sweet potatoes. However, there are ways to offset and reduce your personal carbon footprint. 

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

How Can You Reduce Your Carbon Footprint When Shopping for Sweet Potatoes

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

1. Shop locally and seasonally: Sweet potatoes are in prime season from fall to spring. Buying from local farms reduces the carbon emissions produced and makes it a much more sustainable choice. If you are near a local, small-scale farm, which harvests by hand, your purchase will be even better for the environment.
2. Choose organic: Organic sweet potatoes produce 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. Buy plastic-free: Avoid pre-processed and packaged sweet potatoes, and instead opt for whole, loose produce. This will decrease the overall carbon footprint of your purchase massively.

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

Sweet potatoes have a low carbon footprint when compared with other vegetables and a very low carbon footprint when compared with other foods. However, you can try to reduce your carbon footprint even further by eating organic, reducing food and plastic waste, and purchasing local, seasonal produce. When you do enjoy sweet potatoes, think about whether you can offset the carbon emissions created, to make this healthy snack a more sustainable option!

Stay impactful,

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