On the 8th of September, documentary platform, Waterbear, launched a new feature-length documentary, SLAY. As is often the case with this kind of film, the production is very slick and engaging. SLAY claims to reveal how 2.5 billion animals are killed every year for leather, wool and fur for the fashion industry and the alleged unethical and environmentally damaging practices that underlie those industries.

But does it actually do that? And is there any truth in the claims made?

As Leather UK is the representative association for the UK leather industry, this analysis deals only with the claims made about leather. Comments are given in the order that issues arise in the film:

‘Using leather is so ingrained, people forget that it comes from an animal’ – this comment is made early in the film and to be fair, is partially true. Several consumer surveys have shown that consumers do not understand the provenance of leather, with some unaware that it comes from an animal and more than half believing that livestock are reared specifically for leather production. Leather has been with us for so long, that it is sometimes easy to overlook it.

There is a pressing need to educate consumers on where leather comes from and to explain that it is a circular, upcycled product from an unavoidable by-product (more on this later) that will exist regardless of whether or not it is turned into leather. As found by the Leather UK consumer survey, once consumers understand this, they are more inclined to use leather than to see raw materials wasted. And this is only one of many good reasons to use leather.

Pollution and impacts on human health - The film investigates tanneries in Kanpur, India giving attention to the discharge of untreated Chromium-containing effluents and their impact on the local environment. A number of human health issues are also linked to leather manufacture, with Chromium III inappropriately described as ‘highly toxic’; chromium III presents a limited risk to human health .

The choice of Kanpur, an area known for unacceptable manufacturing practice, is quite deliberate and filmmakers clearly intend to give the impression that the leather manufacture and associated issues shown in Kanpur are representative of the global leather industry. However, this is most certainly not the case for the global industry or even some of the industry in India. While India is a significant producer of leather, and Kanpur may represent 4% of global leather production, the vast majority of the world’s tanneries are subject to stringent environmental, health & safety and worker protection legislation. It notable that the film does not present any other examples of poor environmental practice elsewhere in the world.

While situation in Kanpur cannot be condoned, it is the product of a number of issues which are common to many manufacturing sectors in the global South, including little or poorly enforced regulation, demand for ever cheaper products and poverty. The same pressures have given rise to the devastation of the Citaram River in Indonesia by the textiles sector. This does not excuse poor practices and these should be addressed in the leather sector and others. However, it is important to recognise that these issues are in no way intrinsic to the leather industry.

‘According to the Sustainable Apparel Coalition, leather has one of the worst effects on the planet’ – The film uses the Sustainable Apparel Coalition’s (SAC) Material Sustainability Index (MSI) to suggest that leather has a much bigger environmental footprint than other materials. However, it is well known that the scores used in the MSI cannot be compared between material groups, such as polyester and leather, a fact acknowledged by SAC Vice President, Jeremy Lardeau and in SAC’s own guidance on how to use the MSI. In other words, it is not possible to claim that leather has the worst effects of any material on the planet on the basis of the MSI because the MSI cannot make those comparisons.

Furthermore, the MSI has been discredited as a measure for the impact of materials, as it is based on out-of-date, incomplete or inappropriate data and a limited methodology. These points were raised when the International Council of Tanners called for MSI for leather to be suspended, on the basis that did not properly reflect the impact of leather. This position was subsequently vindicated by the decision of the Norwegian authorities to ban the MSI for consumer-facing claims of sustainability for cotton products as the claims made by the MSI could not be supported.

Looking at the MSI database, it is clear that the generic score for leather is wildly inaccurate, as shown by the up-to-date, verified scores and far lower scores for leather that have been submitted by a number of tanneries.

‘Leather is one thirsty product’ – It is claimed that, according the FAO, the water footprint for one hide is 100,000 litres and that it takes the same amount of water to make a pair of shoes as a human would be recommended to drink over a 10 year period (7300 litres). The huge figure for a hide is a misrepresentation of the water footprint of leather as it includes the water associated with livestock rearing; and even here it is highly misleading as 93% of that water is ‘green water’, also known as rain, which will fall on fields whether there are cattle in them or not.

In fact, the relevant fresh (blue) water input for the manufacture of one hide of leather, including the rearing of livestock, would be about 4000 litres. Of that, and as reported in the Social & Environmental Report of the European Leather Industry 2020, the average water consumed in European tanneries is 121 litres per square metre of leather, i.e. processing a 5 square metre hide to leather would use about 600 litres, or about 44 litres for the 4 square feet of leather in an average pair of shoes. Even at the global level, the average consumption would be about 1000 litres per hide or 1% of the figure claimed in the film. Water conservation is a constant goal for the leather industry and many tanneries use much less than the average.

‘Skins are very valuable’The film asserts that the hide is not a by-product and points to the fact that the leather industry is worth 100s of billions of dollars as evidence of this. This is patently untrue and economically illiterate.

The hide is undeniably a by-product, as acknowledged by the WWF , who state ‘Leather is entirely a by-product of the beef and dairy industries’. On average, the hide represents only 1% of the animal, assuming it has any value at all; it is estimated that up to 40% of hides are simply thrown away . The situation for small skins, such as sheep and goat, is far worse and represents a terrible waste of raw material.

Furthermore, economic analysis has shown that demand for hides has no direct impact on the rearing and slaughter of animals ; livestock are not reared for their hides and skins. The value in the leather supply chain is value added downstream from farming, by tanners, manufacturers and brands, of which the farmer receives nothing. The brand has far more impact on the value a luxury handbag than the materials used to make it. For example, put Stella McCartney on a plastic bag and it will sell for £650, considerably more than the value of the polyester and polyurethane it is made from.

It would be better if we threw those skins away…’ – Reference is made to studies that allegedly show that it would be better for the environment if hides and skins were thrown away and allowed to rot. In fact, the claim is based on only one calculation , by Circumfauna, an initiative of Collective Fashion Justice. A detailed rebuttal of the calculation can be found here but in brief, the premise is deluded, the calculation fatally flawed and the conclusion the exact opposite of what it should be.

Demand for leather is playing a role in deforestation in the Amazon – Eighty percent of deforestation in in the Amazon is linked to cattle rearing and this is extrapolated to claim that this is being driven by demand for leather. The truth is that, as already shown, hide and leather production does not drive livestock rearing. Livestock production would continue even if no leather was made. The lack of influence that the leather industry has on upstream livestock practices has been recognised by the WWF.

However, the leather sector recognises and supports the need to protect the Amazon is very keen to remove deforestation from its supply chains and there are many programmes, such as the work being done by LWG, WWF and NWF. The issues are hugely complicated and will require significant effort and investment to resolve but the industry is committed to deforestation-free leather.

Dangerous Chemicals - One of the more risible claims made is that it is impossible to consider leather a natural product because of the long list of ‘dangerous chemicals’ used in its production. With regard to chemicals, there are two issues to consider here: firstly, chemicals are everywhere and used in the production of almost everything; secondly, chemicals are only dangerous is they are not managed correctly and leather and leather production are subject to the same regulations for environmental and worker and consumer health protection as any other product. This includes the hazardous chemicals used to make plastic for synthetic or faux leather.

More importantly, processing a hide to leather does not stop it being a natural product. The very large part of the material remains protein, even if stabilised. It is curious that the alternatives to leather (discussed later), are almost all entirely dependent on plastic for any functionality and yet are still described as ‘plant-based’. Mycelium products are tanned and finished in tanneries but their chemical content is never discussed.

Leather is obviously a natural product, derived from a natural raw material and returning to nature at the end of life. Plastic, on the other hand, is neither.

‘Faux leather is a life-saving fabric.’ – The previous point segues nicely into the most stupid claim in the film, that faux leather is a life-saving fabric. Regardless of the interpretation, it is a patently nonsensical claim. Substituting leather for faux leather will have no impact on the number of animals slaughtered for food, as previously discussed. And this is before all the issues with faux leather around fossil fuel inputs, lifespan and disposal at end of life. Faux leather is plastic with all the problems inherent with that.

Alternatives to leather - The film concludes with the suggestion that leather can be substituted with alternatives, including Pinãtex, Desserto and lab-grown leather. Clearly there is a market for alternative materials as some consumers do not want to use animal products.

However, it is important to understand that nearly all these products are plastic based, none have the performance characteristics of leather none have the performance characteristics of leather  and will in in all probability produce lower quality products with shorter lifespan and limited repairability, meaning they will be thrown away sooner. Very few are available at any scale and lab-grown alternatives, such as Zoa, are not much past the concept stage and certainly not scalable, even to niche luxury applications.

Most importantly, where leather is substituted, it is almost always with plastic.

It is only right that all materials should be subject to scrutiny and leather is no exception. Consumers expect transparency and it is important that they understand the implications of the materials used in the products they buy. Unsurprisingly, ‘Slay’ adds nothing to that conversation and simply revisits tired tropes about leather to play to an agenda that has little interest in the truth.

In the Waterbear film ‘SLAY’, it is claimed that would be better for the environment if hides and skins were thrown away and allowed to rot than to process them to leather. The claim is supported by reference to a calculation by Circumfauna, an initiative of Collective Fashion Justice. The problem is that the calculation and the rationale for it are nonsense.

Circumfauna assert that because the emissions from letting hides rot would be less than those from processing them to leather, which will eventually be discarded or incinerated, that throwing the hides away is the best option. They allege that this is the case even if the leather that would have been made is replaced by synthetic leather.

The problem with this is argument is that it would also apply to the oil from which synthetic leather is made, which would produce far fewer emissions if left in the ground. And synthetic leather will also eventually be discarded or incinerated so by that logic, it would be better to not make it either. In fact, there are no raw materials that can be processed to final products without increasing emissions; iron ore has no emissions but the emissions from steel production are huge. The idea that raw materials should not be processed because it will increase their carbon footprint is bluntly, ridiculous.

There are also significant issues with the calculation itself. Circumfauna acknowledge that if leather was not made, synthetic leather could be used instead but claim that this would still be less impactful than making leather. However, using their numbers, it is clear that this not the case.

So, if hides are left to rot and the potential leather is replaced with synthetic leather, the emissions would be:

Which equals 109.95 kg CO2e/m2 total emissions.

The net gain is almost zero. This an insignificant difference even before considering the other issues around plastic use and the fact that plastic products will be replaced more frequently that leather products, necessitating greater volumes of material and therefore, more emissions.

However, there is a more fundamental flaw in the calculation. The start point for the calculation are the CO2e emissions from 1 tonne of raw hide (624 kg CO2/tonne). In order to compare the emissions of leather and synthetic leather in square metres, Circumfauna calculate the number of hides per tonne of raw hide and then the multiply that by the square metres of leather from one hide. To do this this, they use an average hide weight of 6.1 kg taken from a UNESCO report. On this basis, they calculate that a tonne of raw hides would amount to 163.93 hides

The problem here is that the value in the UNESCO report refers to finished leather and not to raw hides. As such, the 6.1 kg figure is completely wrong. In fact, according to FAO statistics , a raw hide weighs on average about 26.7 kg. This is confirmed by the EU PEFCR for leather which gives an input flow of 7.06 kg of raw hide per m2 of leather. As such and using the Circumfauna figure of 4.41 m2 of leather per hide, a raw hide would weigh 31.14kg

If we take an average between the FAO and EU figures, the average weight of hide would be 28.9 kg. On this basis, the number of hides per tonne is:

This significantly changes the calculations of CO2 emissions per m2 of rotting hides:

Using the correct weight for raw hides, emissions per m2 rise by a factor of over 3.5. If this corrected value is used in the initial calculation:

The emissions from allowing hide to rot and replacing the potential leather with synthetic leather rise to 112.88 kg CO2e/m2 total emissions.

This is 2.88 kg CO2e/m2 higher than the emissions figure for leather production given by Circumfauna. Factor that by around 2 billion square metres of leather production per year and the result would be an additional 5.76 million tonnes of CO2 emissions arising from substituting leather with plastic.

In other words, using Circumfauna’s own calculations but with the correct value for the number of hides in a tonne, it is clear that turning hides, that will be produced whether they are used or not, into leather is a better choice than substituting leather with plastic synthetic leather.

For no apparent reason, the calculation also includes a reference to carbon to methane conversions. Given the figures used by Circumfauna this is completely unnecessary as they are all presented as CO2e and therefore, directly comparable, and no figures for methane are actually given. Furthermore, there is no conversion factor given from carbon or methane to carbon dioxide, which would be needed given that all the data is presented as CO2e. All of which speaks to the unscientific nature of the calculation.

However, it raises an interesting question about methane. It is probable that under the anaerobic conditions of a landfill, hides would decompose to methane, which would ultimately oxidise to carbon dioxide. The figure for CO2 emissions from rotting hides is presented in absolute terms, i.e. 1 tonne of hides produces 624kg of CO2. This is irrelevant for the purposes of the previous calculations as the ratio of CO2 to CO2e is 1:1, but it provides a basis to calculate the likely methane emissions.

So what are the implications of rotting hides producing methane?

The molecular weight of CO2 is 44 and for methane (CH4), 16. As such, the mass of methane required to produce 624kg of CO2 is:

So assuming complete degradation of 1 tonne of raw hides in anaerobic conditions, 226.9kg of CH4 would be produced. CH4 has global warming potential 28 times greater than CO2 over a 100 year timeframe, as used to calculate CO2e. As such, the CO2e emissions of 1 tonne of rotting hide could be:

If this figure is used in Circumfauna’s calculation, and even if we accept the erroneous figure of 163.9 hides per tonne, the emissions of allowing 1 tonne of hides to rot amount to 118.78 kg CO2e per square metre of leather replaced by synthetic leather:

Using the correct hide number (34.6 hides per tonne), the methane emissions per square metre of rotting hide plus producing synthetic leather rise to 41.63 kg CO2e per m2, a total of 150 kg CO2e per m2, far in excess of the emissions of leather production calculated by Circumfauna. This is all based on Circumfauna’s assumptions but even if CH4 constituted only 10% of the hide emissions, it would still be better to convert them to leather than to let them rot and replace leather with plastic.

The calculation by Circumfauna is demonstrably false. Substituting leather with synthetic leather is not an environmentally sound choice even before consideration of the issues around using plastic, the durability of leather, end of life and so on.

In summary, the premise is deluded, the calculation fatally flawed and the conclusion the exact opposite of what it should be.

As part of Leather UK’s educational remit, we address misinformation and falsehoods about leather.

It’s important that we stay abreast of what consumers feel about the issues that matter to our industry. Attitudes and habits are changing at pace. We can’t rely on what we think we know about people and how they view leather. We have to go out and ask them so that we stay informed and remain relevant.

Our newly launched research report carries the results of what we discovered when we surveyed 2,000 UK adults. We wanted to understand consumer knowledge around leather and its origins as a by-product of the food industry. The lack of knowledge we unearthed surprised us.

We hope you enjoy reading the report.


Inforgraphic page


Download the report here.

View the report online on ISSUU.

At Leather UK, we know that leather lasts a lifetime. As borne out in our findings from the Leather and the Consumer - Research Report, many consumers regularly purchase new or second hand leather goods. We discovered two-thirds of those who buy or use leather said it was because leather could be trusted to last; and more than half said they bought leather because it’s a high-quality material.

And we know that leather-made items often have their own special story, which is why we’d like to hear and share yours.

We’ve now started collecting stories about treasured leather items and need your help – do you have a leather item with great sentimental value?  Did you commision something bespoke? Or just something that means the world to you?

Please fill out the relevant form here,with images if possible, and we would love to tell your leather story on our Instagram page. Thank you.

Due to its link with the meat industry, leather is often claimed to be a cause of the deforestation in vulnerable environments, such as the Amazon. Reports by NGOs have attempted to associate fashion brands and automotive companies to deforestation and leather is one of the commodities that may be subject to new due diligence requirements contained in proposed regulations in the EU, UK and possibly, the USA.

These concerns have given rise to considerable activity by the industry to improve transparency and traceability within the leather supply chain. Action has been taken to ensure, as far as possible, that the leather supply chain does not contain hides sourced from illegally deforested areas and to give confidence to downstream customers and consumers that their products are not contributing to deforestation.

However, it must be understood that leather does not drive the rearing of livestock. The production of leather is all but incidental to that. By extension, it does not drive deforestationResearch at the University of Montana has shown that demand for hides for leather has no direct influence on the number of animals reared and slaughtered. This means that even the best efforts of the leather sector will have a limited impact in the fight against illegal deforestation.

It must also be recognised that the illegal deforestation in the regions of concern is due to corruption, abuses of power, ‘land grabbing’ and ‘cattle laundering’. Even the most diligent companies could be misled on the provenance of the raw materials that they source, particularly from its indirect suppliers. Moreover, most tanneries are small, which exacerbates the challenge. As a customer of the meat industry, leather manufacturers are excluded from the first stages of the supply chain and are not involved in the sourcing and tracing of livestock. Furthermore, hides or skins are of little importance to the meat value chain; hides may represent as little as 0.8% of the animal’s value, and globally, up to 40% are simply thrown away.

The leather sector has very little scope to influence the upstream supply chain. Farmers are paid for the whole animal and receive no premium for the hide or skin. As such, hides and skins have no influence on the rearing of livestock. Hence, while the leather industry supports the elimination of deforestation-sourced raw materials from its supply chain, the limitations on its influence on that part of the supply chain must be recognised and expectations must be tempered with pragmatism. Stigmatising leather by defining it legally as a deforestation risk product is unfair and unhelpful.

Nonetheless, the global leather industry does not deny its place in supply chains that carry deforestation risks, and it will play its part in seeking to resolve the issues by pushing for increased transparency and traceability of raw materials. By engaging with our suppliers and insisting on change, leather manufacturers and their customers can be part of the solution.

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