Russ Roberts: Our topic for today is the environmental case for eating local food and the concern many people have about what are called food miles. Let’s just start with the obvious seeming truth that importing food or eating food that comes from far away would seem to be worse for the environment than food that is nearby. Is that true?
Hannah Ritchie: Not really. The rationale for it makes sense when you think about it. Food is transported across the world. We know that transport tends to emit CO2 because we burn fossil fuels to drive our trucks, fly our planes, our ships. So, you would think that the further a food has traveled to reach you, the more the CO2 has been emitted in the process. That is generally true, but I think what people get wrong is that when we look overall at the carbon footprint of our food, the transport component for most foods is very, very small. So, in reality, the distance your food has traveled to reach you often makes a really, really small part of the carbon footprint of the food that you’re eating.
Russ Roberts: Why would that be? We know that, as you say, travel generally is going to have to burn carbon–unless you’re on a sailboat. But, in general, transportation is carbon intensive. Why isn’t food miles, the distance that food has traveled, an important contributor to the carbon footprint of a particular food item?
Hannah Ritchie: I think there’s two key reasons here that people get wrong. I think one is that people massively underestimate the amount of emissions that come from just producing food in the first place. So, the emissions from land use change, whether that’s deforestation. The emissions from on the farm–so, that’s cows burping methane. Rice emitting methane. Putting nitrogen on the soil and fertilizers. That emits a massive amount of greenhouse gases. And, when we look at the differences in the carbon footprint between foods, they’re really, really massive.
So, I think people might have in their head that maybe the differences are maybe 10 or 20%. So, some foods have 10 to 20% higher emissions. When we look at the differences in carbon footprint of foods, between the highest and the lowest, we’re talking about 10 to 50 times as much. So, a kilogram of beef will emit 10 to 50 times as much emissions as tofu or soybeans.
So, when you then look at the emissions from transport, they might go up and down depending on how far it’s traveled. But, overall, that’s a really, really small share and pales in comparison to the 10 to 50 times difference between different foods.
Russ Roberts: So, being in Israel, if I were to eat tofu imported from Australia–just to pick a place that’s very far away–that would have a much lower carbon footprint than my neighbor’s cow–
Hannah Ritchie: Yeah, exactly–
Russ Roberts: if I was eating beef. ‘But, it’s local. I’m environmentally friendly.’
Hannah Ritchie: Sure. I think the other core argument there in terms of explaining why the carbon footprint of transport is so small is, I think, especially when we think about international travel. So, when people think about food being transported to them from across the world, they imagine that it’s coming by plane, right? But that’s just not the case. It’s very, very rare that foods would be transported by plane because it’s expensive and it’s energy intensive. Most food internationally comes by ship. And, actually shipping is very carbon efficient. So, you’re going to emit 10 to 20 times less CO2 than trucks per kilometer and 50 times less than flying. So, most of your soy or your avocados are nearly always coming by ship and shipping actually has a very, very small carbon footprint.
Russ Roberts: The reason I love this, of course–well first of all, I love bringing comfort and solace to my listeners. Those of you who are eating imported food from far away, which you can now maybe–depending on what it is, you can do it with a slightly cleaner conscience. But, it’s a beautiful example of economics in action or what is becoming the motto of this program, which is: It’s complicated. Something that seems obvious, that things that come from farther away certainly are much worse for the environment. Well, they’re a little worse for the environment than eating an avocado from next door–perhaps, and we’ll talk about that in a minute. But, an avocado from far away might be slightly worse than an avocado from next door, but it’s surprisingly small. And of course, what’s often forgotten is that the international component of the transportation is also relatively small. Depending on the size of your country and the efficiency of its transportation system, the domestic cost of that food item to get to your door or to the grocery nearby are quite a bit often underestimated.
Hannah Ritchie: Yeah, definitely. I think what people underestimate is the emissions from trucking, like, domestically within a country. So, for example, in the United Kingdom we might say, ‘It’s British beef, so it’s local.’ But actually the emissions from trucking beef from a farm–I live in London; I don’t have a farm next door–so, getting beef there, there is a substantial carbon footprint in trucking that to me. So, local doesn’t really mean local for everyone.
I think the other key point there–I don’t want to put across the message that food miles don’t matter at all. I think, like for like, obviously it doesn’t necessarily make sense to import something from the other side of the world if you can get it next door. What I think people get wrong is that they just get the hierarchy wrong in terms of what matters the most for the carbon footprint of their diet.
So, people will automatically put local at the top when actually in terms of the hierarchy, there are several things well above that. And, maybe if you take those off and consider those, then you can focus on the local aspect. But, most people put it at the top, which is just incorrect.
Russ Roberts: I think that local point is quite subtle and quite beautiful. To walk across to your neighbor’s orange tree and pick oranges and take them back to your place is radically different in terms of carbon footprint from buying anything in the store. Because, almost anything in the store has come by a truck, and trucks use a lot of carbon to get around. And, even in a small country like England, the United Kingdom, it’s not insignificant. And, for a large country like the United States, to get your avocados from California to Florida, I assume that’s mostly going to come by truck. There’s no boat and they’re not going to make it by plane, right?
Hannah Ritchie: Right. Exactly. We will get onto this paper. But there was one paper that came out which was arguing recently that food miles did matter a lot and that eating local was a really important thing to do; and it was published in Nature Food, so it got of course lots of attention. But, actually when you dug into the study–actually, there was various flaws of the study–but when you dug into it, they ran a scenario where they said, ‘Okay, every country in the world is going to go for this,’–like, this is very hypothetical, ‘every country in the world is just going to have a nationalized food system. So, there’s going to be zero international trade.’ And, they modeled what would happen to food transport emissions. And, basically the results they got is that you would reduce food emissions by 1.7%, so, less than 2% for the whole world going for a national food system. And, one of the key reasons for that is although you were reducing emissions from shipping or small amount of flying, you were displacing that by having to truck things around domestically. Because, a local food system for most people, it’s not realistically getting it from your local farmer. It’s getting it from 50 miles away or more.
Russ Roberts: Well, actually it’s an underestimate of the effect because food would be so expensive, a bunch of people would die; and then there’d be less food transport, probably. So, it’s probably bigger than 2%, but it’s not really a good story. Or 1.7%.
Hannah Ritchie: Yeah. That was a very hypothetical scenario. And, I think the key point there is the result of a reduction of less than 2% did not match the title or the subtitle, which was saying the eating local was really important because the result just didn’t match the message.
Russ Roberts: Yeah. We are going to talk about that.
Russ Roberts: So, let’s turn to that now. I don’t mean to disappoint you, but not everybody is excited by Nature Food. Many of us have never heard of the journal. I looked it up after I read your article; I assume it is part of Nature, which is a very prestigious science publication. So, they have started a journal called Nature Food to look at these kind of sustainability issues, or maybe other issues related to hunger and poverty. And, this splashy article was that food miles are 20% of emissions. And, you had many critiques of the article; and we’ll post both the original article and Hannah’s piece on it.
But your point was–first, one of your points was that they mis-measured emissions; and secondly that they redefined food miles. What did they do to food miles? How should we think of food miles generally? What’s the consensus? How is it generally thought of and what did they do that you thought was kind of strange?
Hannah Ritchie: Yeah. Food miles is defined as the distance that your food has traveled from production–so from the farm–to reach you, the consumer. And, that’s the transport of food. The transport of food is the key point there. It’s not the transport of anything else: it’s the transport of food. And, that’s how it’s been defined in the scientific literature. I think that’s how the public recognizes and understands that term. And, actually the authors of this study stated that in the opening paragraph that this is the definition of food miles.
What they did in the study was basically redefine that to not only include the transport of food, but also the transport of everything upstream of that. So, fertilizers, machinery, livestock, fuel for cooking the food. So, basically the transport of everything that you might consider as inputs into the food system, which is why you just get a much bigger number, because we ship fertilizers around, we ship pesticides around.
I think what’s really important about that redefinition–I think it’s framed to quantify that. It’s useful to know what that number is and that might lead to important policy decisions. But, it’s not good to label that as food miles and reframe that as being important for local food because the transport of fertilizers, pesticides, etc., has nothing to do with eating local food.
Russ Roberts: Yeah, that’s cool.
Russ Roberts: I want to give my favorite example of these kind of surprising or counterintuitive results on environmental transport and environmentalism generally. About–I don’t know how long ago, maybe 30-ish years ago–there was a big environmental attack on juice boxes. And, in particular a type of juice box, which a lot of children–I don’t know if they still exist. I think they do. In English, they’re called aseptic–I think is the correct title. They basically allow the juice to be stored without refrigeration. And, it’s a very thick plastic paper box that you could jam the straw into. This may be familiar to young children listening–which is a very small number. But, maybe to their parents or grandparents–that you would jam the straw into the box. And then you’d get the juice out.
And, environmentalists hated this product because the box is a lot of packaging for the juice. And, they encouraged people to stop buying these and to either squeeze their own juice or buy juice in other kind of containers.
What was forgotten in this analysis–and I got this from an executive at Coca-Cola. Coca-Cola I think at the time and maybe still does own Tropicana, which is a big orange juice company. And, they were under attack. And, this really bothered him because he understood that squeezing your own orange juice–which has zero packaging, zero–because the orange comes in its own package and you squeeze it into your own glass. Multiple use item.
Well, that sounds fantastically better than surrounding the juice with these boxes. Forgetting the fact that–and it’s very analogous to your point–forgetting the fact that transporting oranges is remarkably less efficient than transporting juice.
If you transport an orange, an orange is a sphere. It’s going to be transported in boxes. But, the number of oranges you can fit in a box and then pile into the truck is going to be radically–the amount of juice that you can transport effectively through a truck that way–is going to be radically smaller than squeezing the juice at its source, putting it in a box that is rectangularish, which you can stack and then use the space on the truck extremely efficiently. [More to come, 14:30]