What’s the problem with leather in our climbing shoes?

Or any shoe, for that matter. Or any item, garment or piece of upholstery. I may use the leather for our climbing shoes in the title of this blog, but the problem leather has lies much, much deeper in the industry itself. Now, there are a few assumptions I want to address in this blog that should clarify that I’m not opposed to leather per se, but a systemic shortcoming in the industry. This should help you to make up your mind, at least with some more information.

Just to be clear, in the header you see a climber wearing a pair of climbing shoes. It’s purely illustrative, I can’t tell what these shoes are made of or am trying to insinuate anything about the brand. 

Leather as a by-product

Ok, so I’m going to start with what leather actually is. It is the treated (read: tanned or processed) hide or skin of a mammal. By treating this hide/skin with chemicals, we prevent decay and enhance its natural properties. This is done in such a manner as befits the final use in an end product. A car seat has different requirements than a climbing shoe, for example, and a working boot needs to be more resistant than a supple luxury handbag. 

One of the important and verifiably true arguments in favour of the use of leather is that it is a co-product or a by-product of the meat industry. This is irrevocably true, and currently, there are enormous amounts of animal hides either buried or burned because people choose vegan materials yet consistently eat meat. That sums up an alarming trend very briefly, which you can read more about in this exemplary Bloomberg article (while the article concerns the USA, the problem is global). The argument that leather is a co-product is no longer valid; thus, as the value of hides has plummeted, the amount of them simply incinerated or put in landfills is, in fact, becoming a worrying environmental issue. At the same time, we’re creating more and more plastics, which are equally if not more so problematic for our long-term environmental concerns. Even wonderful materials, such as pineapple leather, often consist of high percentages of petroleum-based compounds like polyurethanes. Plastic, you know, the stuff in our oceans. There are promising things on the horizon, but we’re not quite there yet and at the same time these by-products are piling up. Turning hides into leather can actually be considered the lesser of two evils (or three, if you consider plastic as the third option), but here lies the problem with leather… its process.

The secretive process of tanning hides

For a hide to become leather, we need to tan the hide with a chemical process. There are various forms of tanning, generally to be distinguished in these 4 categories:

  • Natural tanning – using tannins and animal by-products, like brains, the way our ancestors did – a very slow, and time-consuming process.
  • Wet-blue tanning – tanning using chemicals, with chromium as a premium component. Very fast and effective, often very bad for the environment (though chemical reclamation has changed this a lot).
  • Wet-white tanning – alternative method to chromium tanning in order to make a chromium-free leather. More expensive, yet just as effective.
  • Green tanning – alternative and experimental methods that basically rely on natural tanning methods. 

You won’t find naturally tanned or green-tanned leathers in your climbing shoes, nor the green-tanned leathers, as these are very expensive. During the process of tanning, leathers are also treated to get certain properties, like water-repellency, fire-resistance, better abrasion resistance (kicking the climbing wall much?), tensile strength (get those size 44 feet in a 41 shoe), etcetera and given its first colouring. 

And everyone does it in a different, secret manner, just to have an advantage over the next guy/girl/person. 

Horrible, that leather tanning, right? Let’s diffuse this one: this is a tannery in Morocco, which serves as a tourist attraction. No one tans leather this way any more, who wants to sell to western markets. The facilities that produce your climbing shoes are high-end, certified tanneries. There is a lot of wrong information around…

The result is different products with different unique selling points. You might find that one shoe feels softer while another offers more resistance against scraping the climbing walls. The problem is, then, that it is impossible to process the leather in used climbing shoes because not only are the components and compounds all different, we don’t even know what they are to an extent. 

Breaking down the breaking down

Remember that we made these gym mats from climbing shoe rubbers? In essence, the granulate of these rubbers has a similar problem, their consistency varies, and a glue compound needs to be added to turn them into mats. Leather can not really be reused in a similar manner. There are ways of upgrading leather, which is a great way to make an old leather jacket, couch or pair of boots last for decades, but you wouldn’t really do that with a bit of climbing shoe and then use it again, as the process just doesn’t allow that. And as long as no one wants to make quilts of smelly old leather, we have a leftover material, we can’t recycle or reuse.

While we found ways to create mats from shoes, it is not straight forward or simple.

That leaves recycling into its bare components, as the non-decaying skin can be used as a resource in many other applications, from isolation material, animal feed (you can argue if we should be doing that, though) and health products. Leather is biodegradable, yet that doesn’t mean what most of us think it does. That is not what biodegradable, in the commonly used form, means though. It means it can be biodegraded by treatment, yet that all depends on knowing its contents, which we don’t know. You would have to trace each patch of leather back to its producer, who would have to be able to trace it to its original chemical treatment. This would be a cost-, time- and resource-heavy process that is simply impossible, particularly as there is no bulk solution nor enough profit to be made from this process. There are biodegradable leathers under development, which will be able to degrade by themselves in nature, but these are far from market-ready or usable for every application.

So we burn shit. And much the same goes for plastics that are made under similar, mystical conditions.

In case you were wondering why plastic is not necessarily more cool than leather…

A plea for transparency

In a world where resources are ever more scarce, we need to think carefully about the use of our materials. Leather offers a lot of advantages as a material, and the industry has, though not attaining much in the way of transparency, radically reinvented itself as an environmentally conscious one. I simply can not call it environmentally friendly, based on its alliance with the meat industry, which we all know is fairly horrible. Plastics are, in the way of transparency, a bit easier and may offer a similar solution as we look forwards. Yet to become circular, to find a solution in which we do not keep taking from the earth again and again, we need to investigate how we can reuse these materials without endless chemical investments. To find that path forwards, we need radical transparency and collaboration, industry-wide, and clear standards on production methods. This is the biggest and most daunting step to take, but oh so necessary. 

What can we do?

There is no ready answer to how we move forwards from here individually, as we can not change the industry. What we can do is support brands and solutions that take the right step forward. Some climbing shoe brands have switched to vegan shoes and/or have taken resoling into account in their design and production. Others go for certifications and offer transparency as much as they can. What we can do is be as informed as we can be when we buy a pair and in how we use them (and reuse them). In the end, consumer demand is pushing change, and our voting behaviour changes policy. Like the question of leather or plastic, there are no easy answers available yet. 

Going for a more circular, sustainable industry, means rethinking how we move forward. Scarpa is one of the brands taking that approach, but far from the only one!