What's the impact of food transport on sustainability?

Breakdown of the claim

Why is it so persuasive?

The argument that eating local food is inevitably more sustainable than food that has travelled across the world appeals to several fallacies, making it particularly difficult to undo. Fallacies are arguments which use faulty reasoning, but which in a given context, sound like they should be right (and so often act as distractions). That is what can make them so persuasive. Let’s break down each fallacy and check the accuracy of each argument against the available evidence:

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• 1) Appeal to common sense: Quite simply, an argument which appeals to common sense will sound like it should be right, even when it isn’t supported by evidence or logic. I imagine that when most people think about global warming and its causes, they might visualize motorways filled with cars, or huge industrial plants, all surrounded by big clouds of smoke. If transport causes greenhouse gas emissions, then it makes perfect sense that the further a food travels, the more emissions it will generate; therefore the more unsustainable it should be too. The reason it doesn’t hold up in the context of food production is that it’s based upon an incomplete picture, isolating one factor among many.
• Verification: The concept of food miles isolates a single question: how far has a food travelled to get to that store? But it hides other significant questions, such as: how was that food transported? And more importantly, how was that food produced?

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How a food is transported more or less impacts its carbon footprint. Air travel, for example, generates far more greenhouse gas emissions than boat shipping. However, air travel only adds up to 0.16% of all food transport modes. This means the likelihood of picking up food in the supermarket that was flown there is remarkably small. Avocados from South America, as in The Telegraph’s example, are most commonly shipped by boat.

More importantly, focusing solely on transport hides a much bigger question: how was that food produced? The persuasiveness of an argument tends to rely on two things: what the argument gets us to focus on, and what it leaves out.

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What the claim misses: the wide impact of food production

Despite a recent study suggesting that food transport emissions may have been underestimated, ending all international food transport would only cut food-miles emissions by just 9%, showing that transport’s impact is still relatively small. Food production is what drives the majority of emissions. Practically speaking, this means that when picking out food from the supermarket, how that food was produced tells us a lot more about its carbon footprint than where it came from.

Take tomatoes, for example. Tomatoes grown locally (out of season) in greenhouses have a higher carbon footprint than tomatoes grown in hotter countries, and then shipped to the UK. That is because the energy required to grow tomatoes in greenhouses significantly outweighs transport emissions.

So what does this mean for the consumer? While transport plays a part in our food system’s environmental impact, especially in the most wealthy areas of the world, favoring local food is not enough to reduce emissions: eating seasonally and making dietary shifts, by cutting down on the most high-emitting foods is far more impactful.

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• 2) Appeal to Nature: Further issues arise when we move away from the question of transport in general, and specific foods are isolated. For example, food that comes from ruminant animals such as beef has a much higher carbon footprint than plant foods, whatever their origin. When it comes to meat consumption, the Local Food Myth also appeals to the “Appeal to Nature” fallacy, making recommendations to cut down on animal-based foods harder to embrace.

Consider this post found on X:

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• Verification: The Appeal to Nature fallacy implies that whatever is ‘natural’ is inherently better, and feeds into fears of what is unknown or comes from the outside. The focus is again on food origins, and it hides questions such as: how do we get from that cow to the product on my plate? The argument that animal agriculture isn’t the real problem, and that reducing consumption of animal-based products is therefore besides the point fails to take into account the many steps involved in food production, most of which are far from our representation of ‘natural’. What the above picture doesn’t show us for example, is the fact that 70% of the world’s meat comes from factory farms, not green pastures; and that we would need a lot more land for all livestock to be grass-fed (should we continue to consume the same amount of animal-based products), which would lead to a number of further complications. In other words, most of the negative environmental impact from raising animals for meat consumption are ‘invisible’ and so are not captured by this picturesque image of cows grazing the land. Methane emissions, for example, cannot be seen there, but they’re a very real issue. When you consider the large demand for beef, and the millions of cows living in fields across the UK only, the scale of methane production and environmental consequences is much larger than could be portrayed in this image.

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The transport analogy is unhelpful, because it zooms into a tiny part of a very complex picture. If I’m trying to establish which would be more environmentally friendly, between walking my kids to school and driving them, I am answering a single, straightforward question; transport is the only factor I need to take into account here. But to understand the impact of food production, we need to answer a myriad of questions. When considering the environmental impact of meat, Dr. Cassandra Coburn puts it this way:

“We need to consider all the components that go into rearing an animal for slaughter. For example, what does it take to raise a cow? First you need space - how much? Does that space exist already or do you need to cut down some trees to make a field? Then you have to feed it. Do you have access to pasture, or will you feed the cow grain or feed (and if so, what kind, in what proportions)? It needs water to drink; is there a ready source? Why are you raising the cow in the first place? Do you want to eventually eat its meat, or do you want it for its milk? If the latter, the cow needs to become pregnant in order to begin lactation, which in turn requires a bull at some stage and that brings further complications (doesn’t it always?). Finally, you need to think about other aspects of creating a cow: you’ll either need to shovel the proverbial or accept the harmful consequences of manure running into the water supply.” Dr. Cassandra Coburn, Enough.

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These are just some of the questions that make assessing a food’s environmental impact so complicated. The question “how do you transport a food product to its final destination?” is certainly a consideration, but it comes towards the end of a long process, which the graph below makes very clear. Production is what makes a food have a more or less high carbon footprint.

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Following The Telegraph’s claim, let’s directly compare emissions from local beef vs. avocados from South America, from production to transport:

Emissions Comparison:

Local Beef: Produces 58.8 kg CO₂eq per kilogram. This is without any form of transport, and assuming you are walking to your local butchers’ to buy that food.

Vs.

Avocado from Mexico: Produces 2.5 kg CO₂eq per kilogram, with 0.21 kg CO₂eq from transport.

In other words, the carbon footprint of avocados shipped all the way from South America is more than 23 times that of local beef. While transport leads to some emissions, when it comes to beef, choosing local makes practically no difference to your carbon footprint, which goes down from 60 to 58.8 kg CO₂eq. To understand why that is, we need to consider all of the different elements that are involved in rearing cattle for meat production.

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Source of Beef Emissions:

Farm emissions: Methane from cattle, fertilizers, manure, and machinery contribute 57% of beef’s emissions. Methane is a highly potent greenhouse gas, which in the short-term is a lot more potent than CO2.

Land use change: Deforestation and changes in soil carbon account for 23%. This is important, because our huge appetite for meat is one of the major drivers of deforestation and of biodiversity loss, both of which represent huge losses when it comes to carbon sequestration.

Finally, losses during storage, transport, processing, and packaging contribute 15%.

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• 3) Appeal to Tradition: This fallacy, combined with the above, might be the biggest stumbling block to dismantle the Local Food Myth. Arguments based on the Appeal to Tradition fallacy suggest that something is right because it has always been done this way; or inversely, that something can’t be wrong, because it has always been done this way.
• Verification: Traditions are incredibly valuable. And food choices are very much tied to traditions. They involve our culture and our communities, and are important considerations. But in the context of food sustainability, the implication is that as consumers, we don’t really need to change the way we eat, and that doing so is an affront to our traditions. Again, this argument only takes into account a small part of the picture: the reality is that the amounts of animal-based foods which our society consumes have never been higher; in that sense, they’re not exactly traditional.

If we only think of environmental concerns (without considering health or animal welfare issues), the idea isn’t to ban one type of food, and it certainly isn’t to blame local farmers. On the other hand, systemic changes are needed. But our focus here is the consumer, and how consumers’ choices might support sustainability. The argument to reduce meat consumption is often oversimplified and paraphrased as the unrealistic suggestion for the world to go vegan, entirely foregoing traditions. However, according to Hannah Ritchie (2021),

“[I]mportantly, large land use reductions would be possible even without a fully vegan diet. Cutting out beef, mutton and dairy makes the biggest difference to agricultural land use as it would free up the land that is used for pastures. But it’s not just pasture; it also reduces the amount of cropland we need.” Hannah Ritchie, Deputy Editor and Science Outreach Lead at Our World In Data.

In other words, if we think of the issue in terms of weighing scales, if beef, mutton and dairy are where the pressure is, then that is where we need to act to lift off the environmental burden and help the climate crisis. Other measures can certainly help, but they won’t lift off that pressure.

Does eating locally have no benefits then? It does have benefits, but they’re not environmental. To improve the climate outlook, it is essential to look at the bigger picture so as to achieve maximum impact.

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What about the cherry-picking fallacy?

Analogies are rarely perfect. The analogies used in this article (comparing the impact of different foods, or of the same food grown in different conditions) are intended to raise awareness of the fact that sustainability questions surrounding food production are incredibly complex. They highlight issues which wouldn’t necessarily come to mind, or which might seem counterintuitive - unlike arguments based on fallacies. There are more factors which come into play depending on exactly what question we’re answering (efficiency, economy, ethics, etc.). One counter-argument to categorising beef as a high carbon emission food product is that grass-fed beef contributes to carbon sequestration, which might offset some (or all) of beef’s emissions. But again, this is an incredibly complex issue, which an international research collaboration sought out to answer, producing a report entitled “Grazed and Confused?” This is a snippet of their conclusions:

“The contribution of grazing ruminants to soil carbon sequestration is small, time-limited, reversible and substantially outweighed by the greenhouse gas emissions they generate […] While grazing livestock have their place in a sustainable food system, that place is limited. Whichever way one looks at it, and whatever the system in question, the anticipated rise in production and consumption of animal products is cause for concern. With their growth, it becomes harder by the day to tackle our climatic and other environmental challenges.” Food Climate Research Network, Grazed and Confused? Report

This is why we need to change our mindset, to drive impactful action and meaningful change, without entirely discarding traditions or measures other than dietary shifts.