‘Food miles’ have larger climate impact than thought, study suggests - Carbon Brief (2023)

Global “food miles” emissions are higher than previously thought – accounting for nearly one-fifth of total food-system emissions – new research suggests.

The study, published in Nature Food, estimates the carbon footprint of the global food transport system. The authors assess the entire food supply chain – considering emissions from transporting fertilisers, machinery and animal feed as well as from moving the food itself.

They find that in a single year, global food miles were responsible for 3bn tonnes of CO2 equivalent emissions – 3.5-7.5 times larger than previous estimates.

“Food-miles emissions are driven by the affluent world,” the study says. It finds that while “high income nations” represent only about 12.5% of the world’s population, they are responsible for 52% of international food miles and 46% of the associated emissions.

The authors also reflect on the pros and cons of buying local food – an often-touted solution for reducing food emissions. The study showed that ending all international food transport would cut food-miles emissions by just 9%, highlighting the relatively greater importance of other dietary choices in tackling the climate impact of the sector.

As such, the lead author of the study tells Carbon Brief that while eating local does reduce emissions, this should be paired with eating seasonal produce and reducing meat consumption to limit dietary emissions.

This study presents “a significant deviation from the former scientific mainstream opinion that transport is no major contributor to emissions from the food system”, a scientist not involved in the research tells Carbon Brief. However, he adds that he would “interpret the results with caution”, as emissions may be overestimated in places.

The paper has triggered debate over the definition of the term “food miles”, which typically considers the distance from where the food is produced to where it is consumed, rather than encompassing the entire food supply chain.

‘Food miles emissions’

Feeding the world is an expensive undertaking. Food production uses up half of the Earth’s habitable land, and “food systems” – a catch-all term to describe the way humans produce, process, transport and consume food – are responsible for one third of all human-caused emissions.

Past studies suggest that transporting food has a small carbon footprint when compared to the rest of the food system. However, many do not to account for emissions throughout the entire food supply chain. The new study aims to fill this gap and includes emissions from transporting fertilisers, machinery and animal feed as well as the more obvious shipping and vehicle emissions from sending food products around the world.

The authors consider 74 regions, 37 economic sectors such as chemicals and machinery, and four transportation modes. They then use a “multi-region input–output model” to assess the emissions produced by transporting food and other components of the food system across the entire supply chain. This is referred to as “food-system miles”.

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The plot below shows total food-system miles in “tonne-kilometres”, indicating the distance travelled per tonne of food, on the left. The central figures show the resulting emissions. And total food system emissions, including emissions from land-use change, food production, transportation and consumption, are shown on the right.

Each graphic is split into sectors, including components of the food system such as meat (pink), and dairy (white), as well as related sectors such as manufacturing (dark blue). The bottom panel splits each component into “domestic” (left of the zero line) and “international” (right) emissions and miles travelled.

‘Food miles’ have larger climate impact than thought, study suggests - Carbon Brief (1)

Maintaining the current global food system requires food and related equipment to be transported a total of 22tn “tonne-kilometres” per year, according to the study. This drives 3bn tonnes of CO2 equivalent (CO2e), accounting for almost one-fifth of total food system emissions, it finds.

‘Food miles’ have larger climate impact than thought, study suggests - Carbon Brief (2)

Glossary

CO2 equivalent: Greenhouse gases can be expressed in terms of carbon dioxide equivalent, or CO2eq. For a given amount, different greenhouse gases trap different amounts of heat in the atmosphere, a quantity known as… Read More

Dr Ulrich Kreidenweis – a researcher at the Leibniz Institute of Agricultural Engineering and Bio-economy, who was not involved in the study – tells Carbon Brief that the new study presents “a significant deviation from the former scientific mainstream opinion that transport is no major contributor to emissions from the food system”.

For example, a study published last year finds that transport is responsible for only 4.8% of total food system emissions. However, this study includes refrigeration separately, stating that the “cold chain” of keeping food in a temperature-controlled environment throughout transit and sales accounts for 5% of global food system emissions.

“​​Investigating transportation emissions along the whole global food supply chain is an important step in understanding food-mile emissions”, adds Dr Paul Behrens, an assistant professor at Leiden University, who was also not involved in the paper. He tells Carbon Brief that this paper presents “the first estimate of its kind”.

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It is well known that meat production is highly carbon intensive, requiring extensive stretches of land for rearing livestock and producing animal feed. As expected, the plot from the study shows that meat is responsible for almost two-fifths of total food system emissions – far outstripping any other food type. However, meat accounts for only 4% of all food transport emissions.

Meanwhile, fruits and vegetables are responsible for one-fifth of global food miles, but account for over one-third of transport emissions. This is because fruits and vegetables require energy-intensive refrigeration throughout their journey, and weigh a lot compared to other food types, the study explains.

Global supply chain

The global food system is complex and interlinked. Producing red meat consumed in China, for example, can involve production steps from almost every continent on the planet.

The plot below shows an example of these steps, including machinery, manufacturing and the chemicals required to produce animal feed. Bubbles present food production emissions, while arrows represent the food-miles emissions.

‘Food miles’ have larger climate impact than thought, study suggests - Carbon Brief (3)

To produce red meat for consumption in China, chemicals from Canada are sent to the US by road to grow fruits and vegetables, and to Brazil by ship to grow soybeans. These are used to feed livestock in China. Meanwhile, coal imported from Australia and Indonesia is used for manufacturing, along with machinery from Germany.

To map food-mile flows across the entire global supply-chain network, the authors were required to model more than 30m direct trade connections. The plot below shows the top 100 bilateral flows – from one country to another – of international food-miles emissions (top) and the same per person (bottom). Thicker arrows indicate greater emissions.

‘Food miles’ have larger climate impact than thought, study suggests - Carbon Brief (4)

The plot highlights some of the hotspots of trading activity in certain regions – for example, in Europe and China – while others see less traffic. Most notable is the lack of trading with countries in Africa.

“Food-miles emissions are driven by the affluent world,” the study states. The authors find that high-income countries – where per-capita GDP is above US$25,000 – represent only about 12.5% of the world’s population, but drive around half of international food miles and emissions.

Meanwhile, representing about half of the global population, low-income countries with per-capita GDP below US$3,000 are responsible for only 12% and 20% of international food miles and emissions, respectively, the study finds. It adds:

“High-income regions, including Oceania, Europe and North America, clock up per-capita food miles and emissions 2.7–2.8 times that of other aggregated broad regions.”

Dr Mengyu Li from the University of Sydney is the lead author of the study. She explains that high per-capita emissions in rich counties are in part due to the wide choice of food available there. For example, she notes “the year-round habit of consumers in rich countries for non-seasonal food products that need to be shipped from elsewhere” – which is less prevalent in poorer countries.

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Meanwhile, countries with high populations and large land areas generally have the highest domestic emissions, the study finds. It notes that two-thirds of domestic emissions come from China, India, the US and Russia.

Buying local

Buying locally sourced food is often touted as an easy way to reduce dietary emissions. However, the paper finds that while international transport drives 71% of food miles, domestic transport emissions are 1.3 times higher overall. This is because 93% of international food transport relies on shipping, which has a relatively low carbon intensity, the study says, while 94% of domestic transportation is caused by more polluting road transport. Meanwhile, the authors find that less than 0.25% of “freight tasks” moved by air.

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Nevertheless, switching to a local diet can still reduce emissions – especially in richer countries. The authors found that if the entire world were to switch to a purely domestic food supply, food-miles emissions would be reduced by a modest 0.27bn tonnes of CO2 equivalent. They add that 0.24bn tonnes of this would come from high-income countries.

Carbon Brief asked lead author Li whether eating local is still a useful way to combat food emissions. She says that “localising food supply still leads to emissions reductions”, but adds:

“For consumers, in addition to shifting towards a plant-based diet, eating local seasonal alternatives is ideal, especially among affluent countries.”

The paper “really emphasises the importance of electrifying goods vehicles, switching to rail and/or moving food production closer to population centres,” Behrens tells Carbon Brief. He adds that the paper “combines an impressive set of different data sources in a novel way”.

However, Kreidenweis says that he “would interpret the results with caution”, as the authors “have taken several decisions that may lead to a strong overestimation of food-miles emissions”. For example, he says that the mass of food transported and emissions from some modes of transport may be overestimated.

For example, he says, the study assumes that 99.4% of domestic coal transport happens by road, whereas in reality, trains transport nearly 70% of coal deliveries in the US at least part of the way from mines to consumer.

Li et al (2022), Nature Food. Global food-miles account for nearly 20% of total food-systems emissions. doi:10.1038/s43016-022-00531-w

Update: This piece was updated on 24/06/2022 to include a line on the debate around the term “food miles” that the paper has triggered.

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FAQs

How do food miles affect your carbon footprint? ›

So called “food miles” are likely responsible for about 6% of the world's greenhouse gas emissions, the authors of the study found after calculating that 3bn tonnes of CO2-equivalent was produced in transporting food for human consumption each year.

Why do more food miles contribute to climate change? ›

If your ingredients have come a long way, they may have a heavy carbon footprint. That's especially likely if they arrived by air – due to the high climate impact of planes. After all, flying in food typically creates around 10 times more carbon emissions than road transport and around 50 times more than shipping.

How does increasing food miles lead to a larger carbon footprint? ›

The increase in food miles poses significant problems to the environment because of the energy required to transport the food. This is becoming increasingly important as increasing quantities of our food are now being air-freighted, the worst type of transport for air pollution.

What are food miles and how do they have an impact on the environment? ›

Food miles, a concept from the 1990s, is gaining more attention today, especially in western countries. Food miles are calculated as the distance travelled by any food before it reaches your plate. As transportation increases, carbon dioxide emissions also go up, leading to a rise in global warming.

What are the advantages and disadvantages of food miles? ›

food miles
food miles
Advantages Money from crops can send children to school Young people want to stay in farming Keeping rural community existant Importing crops= invest in futureDisadvantages Global Warming More drought in places like Africa More extreme natural disaters
Evaluation
1 more row
28 May 2013

Why should we reduce food miles? ›

Transporting food is a fuel-guzzling process that eats up fossil fuels. In turn, the use of fossil fuels generates large quantities of carbon dioxide, a heat-trapping greenhouse gas, that warms our atmosphere. Simply put, the more food we transport, the more greenhouse gases we emit.

How much does food miles contribute to climate change? ›

They find that in a single year, global food miles were responsible for 3bn tonnes of CO2 equivalent emissions – 3.5-7.5 times larger than previous estimates. “Food-miles emissions are driven by the affluent world,” the study says.

Why are food miles so important? ›

All food makes a journey from where it is grown or produced to your plate. How far food has travelled is known as its food miles

food miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
. We should be aiming for as few miles as possible. Choosing foods with fewer food miles helps reduce pollution and protect our planet.

What are food miles simple definition? ›

What is a food mile

food mile
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
? Food miles measure how far has your food travelled from where it is grown to where it is eaten. They are one of the indicators which we can use to assess the environmental sustainability impact of foods. The further food travels from farm to fork, the greater its negative environmental impact.

Why is it important to know where our food comes from how far it has Travelled and how it is made? ›

When you know where your food comes from and what's in it, it can be easier to make the right choices for your health. Learning what's in a product before you eat it can help ensure you're getting the right amount of fats, calories, and nutrients.

What foods have the biggest carbon footprint? ›

Beef has the highest carbon footprint of any food. This is because of what is required to raise and farm cattle. Animals used for beef production require a tremendous amount of feed, which must be grown on its own.

How does food impact the environment? ›

Food waste produces 3.3 billion tons of carbon dioxide, a greenhouse gas that contributes to climate change. If food waste were a country it would be the third largest emitter of greenhouse gases after the US and China. By the year 2050 the world's population will increase 33% to 10 billion.

Do food miles matter summary? ›

And for many people, “food miles”, the distance food travels from farm to plate, are a simple way to gauge food's impact on cli- mate change. But it's how food is produced, not how far it is transported, that matters most for global warming, according to new research pub- lished in ES&T (3508–3513).

What is the basis of the food miles idea? ›

Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.

What is a disadvantage of food miles? ›

One of the biggest drawbacks of food miles

food miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
is that it ignores the costs involved in production, as well as inputs such as labour and capital. The “food miles” argument basically suggests that food farmed locally is better for the environment.

What are food miles quizlet? ›

Definition of Food Miles

Food Miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
. - Food miles is a term that refers to the distance food is transported from the time of its production until it reaches the consumer. - In a globalized world food products are transported all over the globe, this makes it possible to have fresh food always available to sell to customers.

What is carbon footprint food? ›

Advertisement. Most of the time, a carbon footprint refers to the amount of greenhouse gases (GHG) that something creates, mainly carbon dioxide (CO2), methane and nitrous oxide. These gases can trap heat in our atmosphere, which causes global warming.

How carbon footprint can be reduced in the area of food and fuel? ›

By making simple changes like eating fewer animal products, using less plastic, eating more fresh produce, and decreasing your food waste, you can cut your personal greenhouse gas emissions significantly. Keep in mind that efforts that seem small can make a big difference.

Does eating local food lower your carbon footprint? ›

Eating local only slightly reduces your emissions

Eating local beef or lamb has many times the carbon footprint of most other foods. Whether they are grown locally or shipped from the other side of the world matters very little for total emissions.

How can food miles be sustainable? ›

What can we do?
  1. Think before you buy - Choose locally grown food that is in season.
  2. Try to buy certified organic food.
  3. Find out about your local farmers markets.
  4. Talk to your local greengrocer, butcher and fishmonger and find out where their produce comes from.
  5. Grow some of your own fruit and vegetables at home.

What is the single most significant cause of carbon emissions? ›

Electricity and Heat Production (25% of 2010 global greenhouse gas emissions): The burning of coal, natural gas, and oil for electricity and heat is the largest single source of global greenhouse gas emissions.

How do you use food miles in a sentence? ›

Examples of food miles
  1. The environmental impact has been seen in so-called food miles.
  2. We can do a great deal to support local sourcing, not only through supporting our farmers in the rural economy but in reducing food miles.
21 Sept 2022

What is the meaning carbon footprint? ›

A carbon footprint is the total amount of greenhouse gases (including carbon dioxide and methane) that are generated by our actions. The average carbon footprint for a person in the United States is 16 tons, one of the highest rates in the world. Globally, the average carbon footprint is closer to 4 tons.

What are the consequences of international food transport? ›

Transportation is the largest overall contributor to greenhouse gas emissions in many developed countries. Because food products often travel long distances to reach consumers, one might expect transportation to be the major food-related contributor to greenhouse gas emissions.

Are food miles bad for the environment? ›

Food miles

Food miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
is the distance food travels from production to when we consume it. Energy is used to produce, package, transport and store food. Even energy use to travel to shops to purchase food is counted. All of this contributes to increased greenhouse gases such as carbon dioxide (CO2).

How much does food miles contribute to climate change? ›

They find that in a single year, global food miles were responsible for 3bn tonnes of CO2 equivalent emissions – 3.5-7.5 times larger than previous estimates. “Food-miles emissions are driven by the affluent world,” the study says.

Why are food miles so important? ›

All food makes a journey from where it is grown or produced to your plate. How far food has travelled is known as its food miles

food miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
. We should be aiming for as few miles as possible. Choosing foods with fewer food miles helps reduce pollution and protect our planet.

How much does food transportation contribute to climate change? ›

Unequal emissions

They found that, in 2017, food transportation added emissions equivalent to 3.0 gigatonnes of CO2 to the atmosphere, up to 7.5 times what was previously estimated (see 'Food transport and production emissions').

What are food miles simple definition? ›

What is a food mile

food mile
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
? Food miles measure how far has your food travelled from where it is grown to where it is eaten. They are one of the indicators which we can use to assess the environmental sustainability impact of foods. The further food travels from farm to fork, the greater its negative environmental impact.

What are food miles examples? ›

"Local" food miles

For example, a gallon of gasoline could transport 5 kg of meat over 60,000 miles (97,000 km) by road (40 tonner at 8 mpg) in bulk transport, or it could transport a single consumer only 30 or 40 miles (64 km) to buy that meat.

What food has the biggest carbon footprint? ›

Beef has the highest carbon footprint of any food. This is because of what is required to raise and farm cattle. Animals used for beef production require a tremendous amount of feed, which must be grown on its own.

Do food miles matter summary? ›

And for many people, “food miles”, the distance food travels from farm to plate, are a simple way to gauge food's impact on cli- mate change. But it's how food is produced, not how far it is transported, that matters most for global warming, according to new research pub- lished in ES&T (3508–3513).

What is the single most significant cause of carbon emissions? ›

Electricity and Heat Production (25% of 2010 global greenhouse gas emissions): The burning of coal, natural gas, and oil for electricity and heat is the largest single source of global greenhouse gas emissions.

Why is it important to know where our food comes from how far it has Travelled and how it is made? ›

When you know where your food comes from and what's in it, it can be easier to make the right choices for your health. Learning what's in a product before you eat it can help ensure you're getting the right amount of fats, calories, and nutrients.

What is the history of food miles? ›

The concept of food miles

food miles
Food miles is the distance food is transported from the time of its making until it reaches the consumer. Food miles are one factor used when testing the environmental impact of food, such as the carbon footprint of the food.
https://en.wikipedia.org › wiki › Food_miles
was developed in the early 1990s by the UK NGO Sustainable Agriculture, Food, and the Environment (SAFE). Since then, food miles have become an important tool in considering the environmental impacts of our eating choices.

How much carbon emissions does food waste produce? ›

About 6%-8% of all human-caused greenhouse gas emissions could be reduced if we stop wasting food. In the US alone, the production of lost or wasted food generates the equivalent of 32.6 million cars' worth of greenhouse gas emissions.

Does eating local food lower your carbon footprint? ›

Eating local only slightly reduces your emissions

Eating local beef or lamb has many times the carbon footprint of most other foods. Whether they are grown locally or shipped from the other side of the world matters very little for total emissions.

How does organic food reduce carbon footprint? ›

Organic Farming Reduces Greenhouse Gases

Because fossil fuel-based fertilizers and most synthetic pesticides are prohibited in organic farming, it has a significantly lower carbon footprint. The production of these farm chemicals are energy intensive.

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