Interviewees
Kerry Senior, director of the UK Leather Federation
Michael Meyer, CEO and scientific director at the independent Freiberg Institute FILK
Transcript:
This is Living Planet.
Neil: OK, so I'm walking through the main market square in Bonn. I'm about to meet Kathleen. She's asked me to join her in a shop, and I don't really know why.
All I know is, is that it's work related. Yeah, I see it over there. There's the sign.
Kathleen: So, I'm just waiting on Neil to come join me, but it seems he's perusing this store full of fine sustainable goods. We'll see how long it takes him to get over here.
Right now, I am in a store surrounded by all sorts of clothing and shoes and bags. A lot of them made of leather, but not all of them, and so I've asked Neil to come down here to see if he can figure out which is leather and which isn’t.
Were you just shopping right now?
Neil: Oh yeah, I was having a look, there was some food for hedgehogs over there. I don't know what that's all about cause I thought this was, I don't know. Tell me more about the shop.
Kathleen: Yeah, so they have all sorts of really interesting items, but, like, they value sustainability. So, a lot of the stuff that you buy here is stuff that you really use for a long, long time. And as you can tell, like one of these products is leather, so if you just want to take a quick look. So, we have leather bags, leather wallets, leather jackets.
Neil: I can smell it, I love the smell of leather.
Kathleen: Yeah, but it's not the only thing they sell here. They also sell a lot of sustainable products made from, like, organic materials. And so, I have 3 pairs of shoes, and we're going to play a little game.
Neil: Oh.
Kathleen: First of all, really importantly, how many shoes do you think are produced worldwide a year if you had to guess?
Neil: OK, let's say 2 billion.
Kathleen: Two billion? Uh more like 24 billion by one estimation that I read. And so then if we're talking about leather, how many…
Neil: Oh, I thought you meant leather…
Kathleen: No, no… I meant total.
Neil: Well then, of course I would say 24 billion. Of course.
Kathleen: Yeah, when it comes to leather shoes, some estimations say that maybe over half of the shoes that are produced worldwide are made of leather, which then, of course, that ties back into the meat and dairy industry, which has a huge carbon footprint, which is part of the reason why we want to see, you know what's better.
So, I have three pairs of shoes. Some of them are made of leather, some of them are not made of leather. Can you guess? Can you guess which shoes are which?
Neil: Well, on the left-hand side, we've got like a sneaker type shoe, a white shoe, white laces. It looks like it might be leather. In the center, we've got like, a hiking boot, brown, looks very sturdy. That to me looks like leather to kind of show that you know, you also would make with leather.
And on the right-hand side looks more like a tennis shoe. Also, white that to me looks a bit artificial, but I'm just seeing the price tag. It's not artificial, is it? This is leather.
It's €200 that that's got to be leather, right? Can I have a look? So, it's made in Portugal. Made from corn waste, bamboo and organic cotton?!
Kathleen: Yeah, right? Interesting, huh? But why did you say it looked synthetic? Because actually, I looked at this. I had to scope out the store before you got here. And I didn't guess that those weren't leather cause to me, they look like leather.
Neil: They do, I mean, what is it? Corn waste?! I didn't know you could make shoes from that, I really didn’t.
Kathleen: What about the other white tennis shoes? What do you think? You've been burned once before, so…
Neil: God, these are also €200. Why is it that shoes are so expensive?
Kathleen: It's that we just don't earn that much money, Neil, that's the problem.
Neil: What are these made of, let’s look at the label. It says “Glattleder.”
Kathleen: You’re going to have to translate for the non-German speakers out there.
Neil: That’s like smooth leather, right? But this to me, it feels like plastic. It doesn’t feel like leather to me. (laughs)
OK, so that's real leather. The other one was like bio-based materials and the one in the center here, this hiking boot…oh, my God, okay, €440?!
You know, I buy hiking boots regularly. I'd never pay this much, but I want to know what this is made of.
This is yak leather?! This is made of yak?!
Kathleen: That’s why it’s over €400, man.
Neil: (sniffs)
Kathleen: Did you just sniff it?
Neil: I met a yak once and it was very whiffy, so I just thought I’d give the shoe a sniff.
Neil: I see belts over there, I’m just going to nip over there because I do need a new belt, I just want to have a quick look at the price range.
Kathleen: Can I follow you?
Neil: Of course you can…. 389 euros for a belt made of horse leather?! Yeah, I think we’re leaving.
So, one reason I wanted Neil to take a closer look at those shoes is because shoes can tell you a lot about leather’s environmental footprint.
Kerry Senior
OK, shoes is a good example because even now it's nearly half of the leather used produced in the world goes into footwear .
That’s Kerry Senior, the director of the UK Leather Federation. He’s, incidentally, a really good person to talk to about leather because he’s an environmental scientist with a doctorate in microbiology.
We’re going to come back to him in just a second.
So, with half of all leather going into shoes, and the footwear industry worth well over 400 billion dollars and growing thanks to greater consumer spending power (especially) in Asia – that means demand for leather is also going up.
And interestingly, this desire for leather is also driving the vegan leather industry.
Because turns out a good number of consumers want the look and feel of leather minus the killing of animals, or minus the eye-watering price tag. That slice of the shoe business is already worth about 39 billion dollars – and is also growing.
They both leave behind an environmental footprint – so which one is the better choice for the planet?
Let’s start with leather.
Most of what you find in the store is not made from yak, like those 400-euro boots that nearly gave Neil a heart attack – it’s generally cowhide.
Before those leather shoes end up on the shelf, they’ve taken quite a long journey.
And a quick warning, their journey starts in the slaughterhouse.
Once a cow has been slaughtered,
its hide needs to be either refrigerated and transported to a tannery ASAP.
Or it needs to be preserved in salt to stave off microorganisms.
That’s how untreated hides can be shipped across the world without putrefying.
Next, is the tanning process. There are generally three ways to tan a hide…
Kerry … which would be chromium tanning, tanning using synthetic chemistries, or vegetable tanning, which uses plant extracts. Once the hide’s been tanned, it’s then in a stable state. It won't putrefy, which is obviously the intent.
And at that point, the leather will go into a finishing process FADE CLIP DOWN
And that finishing process, meaning the look and feel of the leather, will be different depending on whether it’s going to be used in car seats, handbags, or, of course, shoes.
So that’s more or less how leather gets made, and if you were keeping count, there are a lot of environmental factors involved.
First, there’s the issue of raising cattle. Livestock causes around 12 percent of all human-made greenhouse gas emissions, according to figures from the UN’s Food and Agriculture Organization.
The FAO also says that if you only take the agriculture sector into account, livestock is responsible for about 40% of those greenhouse gas emissions – cattle and most of that comes from beef and dairy.
And let’s not forget about water. It takes, on average, over 15,000 liters of water to produce one pound of beef.
And all of this is also really important for understanding where leather’s CO2 footprint comes from – most of it -- over 80% -- comes from the livestock industry. That’s according to a review published UNIDO, the UN Industrial Development Organization, in 2017.
But that doesn’t mean the tanning sector’s pollution is minor. Which brings us to the next environmental concern: waste management. Most leather is tanned using chromium sulphate. And if improperly managed, chromium sulphate can transform
into a compound called chromium VI, a chromium compound which is carcinogenic and can also become a toxin in the local environment.
One study in 2023 by a Bangladeshi university found that leather shavings containing chromium were ending up in local bodies of water. They also noted the use of tanned waste in poultry feed and fertilizers, which could then end up back in humans.
But Kerry argues the big problem here is waste management, which he says is not unique to the leather industry.
Kerry Senior: In certain parts of the world, things are not done as they should be and you can pick any number of industries in these parts of the world and see the same poor practice. The same lack of care for the environment, for workers, for whatever. It's not an issue for the industry, it is for the leather industry as it stands, it's a bigger issue of commercial activity in the world today.
And finally, there’s, of course, the big question of animal welfare. Critics say leather production is contributing to animal cruelty because most of these animals are raised in cramped conditions, solely to feed the world’s growing appetite for beef and dairy. And some claim, for shoes and handbags as well.
But that final point is one Kerry says is just plain false.
Kerry Senior: It's a popular misconception that animals are being reared to make leather. The value of the hide does not make that in any way economically viable, particularly as the farmer of the actual person who's rearing the hide gets absolutely no return for it.
According to Kerry, cowhide in Brazil would fetch maybe $6. In the UK maybe as much as 25 pounds sterling – not even 2% of the value of the meat the cow produces. There’s basically very little financial incentive to sell these hides to tanneries.
So, if you’re wondering why those leather shoes cost so much, the short answer is the price is related to the manufacturing process, not the value of the hide itself.
Kerry Senior: So, the notion that, uh, cattle are being reared for the hides is entirely misplaced.
Ok, so that’s a quick overview of leather. So how does vegan leather stack up?
Just on a side note, in the process of making this episode, I was told by one sales person that there is no such thing as “vegan leather” – much in that way that some people take issue with “vegan meat” being called meat. It’s either meat – or in this case, leather, or it isn’t.
But whatever you want to call it, more and more people want it, especially in Asia which is where over 30% of that demand is coming from, according to US marketing research firm Spherical Insights.
And here’s where artificial leather is the more apt term here, though, because most of what’s being sold is not 100% plant-based at all. In fact, a lot of it is plastic.
Michael Meyer: They are working with fossil-based raw materials. The main polymers which are used are polyvinyl and polyurethanes up to now. And both polyvinyl and polyurethane are mainly made from fossil resources.
That’s Michael Meyer a professor for additive manufacturing of biobased materials in eastern Germany, near Berlin. He’s also the CEO and scientific director at the independent Freiberg Institute FILK”, which researches leather and artificial leather technologies.
Michael Meyer: There are developments where they try to exchange this to the use of bio-based raw materials, but this is just a very small share on one hand. On the second hand, this is basing on bio-based much more expensive.
Michael says bio-based materials tend to be about four to six times more expensive than materials derived from petrochemicals, like polyvinyl and polyurethane.
And when it comes to their environmental impact, there’s no question of their harm.
Not only do petrochemicals contribute significantly to the chemical sector’s carbon emissions, but the plastics they make aren’t biodegradable and are releasing microplastics into the environment.
Leather, on the other hand, can, depending on how the tanning process, decompose within a matter of weeks. A pair of shoes, 50 years, according to Kerry – but what about artificial leather shoes?
Michael says before you get to biodegradability, you need to think about durability. Take shoes made of cactus or mushrooms, for example.
Michael Meyer: This is again a very interesting question. Mycelium-based is produced by biotechnology. So, these are like a fungi and the stability is not as well as we can observe it for leather. So, it's a completely different procedure to make these fibers. For example, making a shoe from this. You can make opera shoe from this, but you cannot make a hiking shoe. It's not possible.
So those opera shoes – or dress shoes – might be worn for a long time, because they’re not used so often. But using artificial leather for a shoe that needs to be worn often. Michael says, what’s on the market is unlikely to hold up as well as leather.
One way manufacturers are trying to compensate for this problem is by using plastic polymers (which are also cheaper than biobased polymers) to improve durability.
Michael Meyer: The cacti-based materials are in principle PVC or polyurethane based synthetic leathers filled with cactus fiber or cactus leaf powder.
… which of course means when they enter a landfill, that polyurethane will take decades to break down… and the microplastics it will leave behind will never fully decompose.
What does make these many and varied alternatives to leather so intriguing – whether it’s plant-based or fruit-based – there’s anything from apples to mangos – is the potential to upcycle natural waste from the agriculture sector.
For example, a pineapple-based leather that uses hundreds of pineapple leaves to produce one square meter of artificial leather.
Or in the case of cacti, growing a plant that absorbs CO2 and uses little water.
In the end, though, the use of fossil-based plastics would be decisive. And so would the impact of scaling up these smaller businesses.
Michael Meyer: If we, for example talk about the pineapple fiber based materials, they are made from pineapple fibers. It's OK in the local production it's it works, but if you scale it up, you get something like a paper industry. So, you have to deliberate much amounts of water and this is cost expensive. So, you have a paper-making process in principle.
Earlier, Kerry pointed out that cattle aren’t being raised for their hides because it doesn’t pay off for the meat industry. And I want to come back to that point, because this also plays into the measure of leather’s environmental footprint.
Kerry Senior: In the world today, probably around 90% of the people eat meat. As long as you eat meat, there will be hides and skins. If you do not use those hides and skins to make something, you have to throw them away. You're talking in the order there of, you know, a billion hides and skins a year being produced by the meat industry. If we don't make leather, we have a waste issue.
We also have a substitution issue in that if you don't put leather into products, people will put something else into products. And as we said earlier on, that will inevitably be plastics because the next gen materials are not at any kind of scale to substitute leather yet.
So, again, looking at the environmental footprint, reducing leather’s impact needs to start with tackling the footprint of the meat industry.
For consumers, it would also involve trying to figure out where the leather itself came from. Though admittedly, and Kerry says this, too, that’s easier said than done. He says traceability needs to improve because it’s entirely possible the leather for a pair made in India might actually come from Brazil, and might have been tanned in China.
And this sleuthing won’t be much easier when it comes to non-animal based leather shoes either. Even a product labeled “bio-based” might not be as sustainable as a company claims.
For example, Michael and researchers at FILK found in one study that a brand using cactus claimed it was free of toxic chemicals and PVC. But in fact, it contained polyurethane and several restricted chemicals – something consumers would not be able to figure out on their own.
Michael says it’s exciting to see how fungi and plants are being used to make leather alternatives, and to see how technology will improve their uses in the future. But he also stresses that their shortcomings largely come down to their role in the natural cycle. Fungi and plants are not built to protect a body in the way an animal hide is.
And here he says it’s important to talk about the place of meat in society.
Michael Meyer: Carbon footprint of the meat industry is as well a very important topic and one can discuss this very intensively. The challenge is ruminant, so cows, sheep and goat are transferring cellulose, which is not digestible by humans into digestible protein, so it's important.
But intensive breeding of animals with soy or plant-based proteins, it can be a problem. But to transfer cellulose to a digestible protein is very, very important that we can use it and do it. And this is the discussion we have with the colleagues from the vegan mindset. I think it's important to discuss always and to have in mind the whole cycle of nature, not only parts.
And animals are part of the biocycle.
The final question we need answered to figure out the environmental impact of leather versus vegan leather is – How long will it be until the other shoe drops…leather or otherwise… right into the trashcan?
Afterall, the benefits of even the most environmentally-sustainable shoes are only as long-lived as those shoes are worn. So, a material that can’t be repaired and worn for years isn’t doing the planet any great favors.
Neil. So Kathleen, what is better? Is it leather or is it synthetic shoes? Can you give a clear answer on this?
Kathleen: I've been dreading this question ever since I started writing the script, so I'm going to preface this by saying this answer is based on where the technology stands now.
If you're talking about … let's say you're sitting in the States and the next state over, they're making plant based shoes from like corn waste or you're in Europe and there's something with apple waste and it doesn't have a long way to go to get to you. Yeah, it's going to have a much smaller CO2 footprint and like lower greenhouse gas emissions. Then I would say the answer is clearly a plant-based shoe would be the better alternative, but that's only talking about the beginning of the life cycle. So, if you're looking at the bigger picture, you can't get away from the fact that, you know, livestock is part of the reason why leather has such a huge impact on the environment in terms of using land, using water, greenhouse gas emissions.
But if you're talking about actually using one of these shoes and comparing these two examples, I would say there's a stronger argument for leather overall, because it's more durable, it's something you can use for decades, and it's more biodegradable. Because even if you have a plant based shoe that has a high percentage of whatever plant based material the fact of the matter is, these companies are still very reliant on polyurethane on PVC, which are fossil-based resources and when they breakdown in landfills, they leave behind microplastic and there's no way to get around that fact.
Neil: OK, so plant based, you've got reservations there, scalability, etc. But I mean this this whole complex with also the meat industry etc and the fact that we're on, we seem to be on a bit of a leather drip because it's a byproduct that otherwise just goes to waste. So, we might as well use it. But I mean what if you know just assuming that, what if the world became vegan?
Kathleen: What if the world became vegan? Well, then that would go back to what Michael Meyer was saying from FILK, which is, you know, we should really be asking ourselves, OK, there are these fantastic technologies that are being used to make a product that imitates leather, but there is nothing on the market right now that 100%. imitates leather as things to know you have the problem with durability and being able to use these materials in the same way as you can leather. So, we've been talking about shoes, but of course leather is used in so many different products that yeah, that would also be the question like is it really worth developing a technology that could potentially become very energy and water intensive, depending on what you're using, for example, like mushroom based is very energy and water intensive because you actually have to grow the mushroom. It's not a natural byproduct in the same sense. But yeah, if we became vegan, I mean, I would assume based on the research that yeah, that that would probably lower greenhouse gas emissions and land use in the way that livestock uses it, because livestock, that's like a third of our crop land on the planet is used for livestock. A quarter of the planet’s land that isn't covered by ice is used for livestock. So, in that sense it would be better, but that would be assuming, like we would just not be using these animals for anything.
Neil: Yeah, I mean, of course there's also then the problem or the possibility, if we went all out vegan that then synthetic would just take over, right?
Kathleen: Yeah, and that's the thing that critics bring up a lot because it's still heavily dependent on fossil-based materials because to fully mimic what leather can do, they haven't found a way yet without using polyurethane or PVC. And what I also found very difficult in researching this and very enlightening reading this report that Phil did, which is to my knowledge, the most thorough kind of look and an independent analysis of like different products that are being labeled as vegan leather or non-animal based, is it like to really know what exactly is in these products is very difficult, because the companies aren't fully disclosing everything which is not uncommon. But there was one point for example, like in this report where they even found a vegan labeled product that was PETA approved, it was made of eucalyptus and pineapple fibers. It actually contained leather.
Neil: How? How does that happen?
Kathleen: So basically like there were three layers that were used in this material, this leather like material. So, the top layer was embossed microfiber material. The back layer was PVC-coated textile and the middle layer was made of what's called leather board, which is basically like the leather shavings. So, something that would go to waste anyway. Now that's a really extreme example. It's really, really strange. But you know their findings in general of like, what percentage exactly of PVC or polyurethane is contained in these materials, I think just goes to show that if you want something that is environmentally friendly, you can't forget to think about plastic and you can't forget to think about what plastic does to the environment in terms of microplastic, because that is part of these shoes. It just is.
Neil: So, I mean, where does it leave the consumer then? Because I'm also thinking, you know, for.
Kathleen: Go barefoot. Go barefoot is basically what I'm recommending at this, I mean like how many, how many pairs of shoes have you bought for yourself this year?
Neil: Let me think. Two, I’ve bought two pairs of shoes this year. And that's sports, both of them. Yeah, one is for running and the other is just a pair of sneakers that I wear to work as well, I'm actually wearing now.
Kathleen: Well, yeah. I was looking at surveys to see how much like how many pairs of shoes people own on average. And according to one survey from the States, Americans on average have about they buy about four pairs of shoes a year, and own about 12 on average. I found one survey from Germany that was saying this from 2017, I don't know how true this is, but women apparently own 20 on average. I feel this is a little bit sexist. And no, actually I.
Neil: I believe that right away,
Kathleen: No actually I don’t believe that.
Neil: Just judging by my wife. Seriously, she's got way more shoes.
Kathleen: I think the larger point that we keep coming back to when we're talking about consumer goods is of course consumerism. So, if you are buying a new pair of leather shoes every year and you're buying a new pair of plant-based shoes every year. You know, it's just going to end up in a landfill that's just more and more ending up in a landfill eventually. And if people are really honest about how long they're using these products, and yeah, if they're wearing something for decades, or if they're only wearing it for a year or two, that's I think the larger issue with this particular good.
Neil: But just I mean also with consumer perceptions regarding leather because I mean, I grew up always leather was it was like a luxury product, right? If it's real leather that's special. You didn't buy that often.
Kathleen: You know, there is the growing trend that people want to do something good for the planet. And if you look around, there is also a huge perception that buying a leather product is contributing to animal cruelty and that is driving the demand for leather, which based on the value of the high because that value of the height isn't even worth 2% of what the entire animal is worth, so to go to all that trouble, basically, if you want to put it that way to raise an animal to slaughter it and then, yeah, just for the value of the high that that doesn't work out mathematically. So, I think in terms of perception, that's also a really interesting point.
But that's actually something I want to ask you about because we didn't really talk about animal cruelty all that much and you did an entire series on meat. Were you reminded of some of the stuff that you had to work on with? I mean, you saw animal slaughtered, for example.
Neil: Yeah. Two calves. Yeah. I mean, the animal cruelty side of things, it's. I mean, just from my experience doing that series back then, it was just so theoretical. When you just push it away, you don't really think about it. You know you have your steak on your barbecue and there's no connection to what actually happened before or went before that. And just seeing that firsthand. I mean, personally, I would recommend that everybody does it and witnesses something like that.
Because for a time at least, it really makes you more self-aware of your own meat consumption and what it means. But yeah, there's no doubt about it. The meat industry, factory farming, our demand for meat, just having meat and supermarkets comes with animal cruelty. There's no way they can do it without. It's just the space issue and the timing and money issue. You have to be fast. It has to be efficient.
And the animals are transported long distances, terribly cramped conditions. It's horrific what's happening every day.
Kathleen: I mean, yeah, I think that's just part of a larger discussion, but to me, you know, big take away is the fact of the matter is we have this product and to throw it away, to throw animal hide away is also a huge waste. I think that merits more discussion, but I also feel like something's going to fall on my head for implying that that in some cases leather is not a bad environmental choice in that sense that we're talking about, Tricky and even you're giving me that look.
Do you have something else to say about plant based shoes.
Neil: No, I don't. But maybe our listeners have, maybe they can write in, let us know, send a voice message if there's anything that you want to contribute or if you have a strong opinion on this or if we got anything wrong or you'd like to correct us, please let us know.
Today’s episode of Living Planet was produced by me, Kathleen Schuster and edited by Neil King. Our sound engineers were Ziad Abou Sleiman and Jan Winkelmann.
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