Fibres & Fabrics

Fibre Briefing: Leather

Probably the most ancient fabric used by humans, leather is a multi-billion dollar global industry. Demand for leather goods is growing – but so is criticism of its severe environmental impact, which is driving a keen interest in sustainable alternatives.

Leather is animal hide that is cleaned of hair, treated (or ‘tanned’) to preserve it and then finished with a specific colour, embossing or feel. Manufacturers then turn this into footwear – the primary use – as well as clothing, fashion accessories, interiors and car upholstery.

Most leather comes from bovine animals – chiefly cows, but also sheep and goats. According to the Food and Agriculture Organization estimates referenced in the Textile Exchange report 2021, around 1.4 billion hides and skins of animals were used in global leather production in 2020¹– around one animal for every 5 people on the planet.

Other hides are used on a much smaller scale for luxury goods, such as snake, alligator, crocodile, kangaroo, ostrich, deer and fish – some intentionally farmed for their skins. In 2020, the global leather goods market was worth around $394.12 billion and it is estimated to grow by an annual growth rate 5.9 per cent from 2021 to 2028.²

The dominant segment in the leather goods market in 2020 was footwear with over a 47 per cent share.³ More than half the world’s supply of raw leather comes from developing countries in Africa, Asia and Latin America. China is the biggest buyer and processor of this raw material – unsurprising given that it is also the world’s leading shoe producer and exporter.

High environmental costs

As currently practised, leather production is linked to some serious sustainability issues, not least as a by-product of the meat industry. Extensive rearing of livestock has severe environmental impacts such as deforestation, water and land overuse, and gas emissions. Clearing of the Amazon for cattle ranching, including for leather, is contributing to climate change.

The Sustainable Apparel Coalition’s Higg Materials Sustainability Index – which measures impact up to the point of fabrication – gives most leathers an impact of 159 (compared with 44 for polyester and 98 for cotton), due to its high contribution to global warming and water use and pollution.⁴

Tanning is the most toxic phase in leather processing, with a high percentage of production still using chromium tanning. Hides are doused in drums of water, chromium salts and tanning liquor to stop them decomposing and to give a supple, colour-fast leather.

It produces a slush of chemicals and gases, including carcinogenic chromium (IV). This is so noxious that strict regulations governing it have forced the closure of tanneries in the US and Europe. According to EPA, 70% of the water pollution in the US comes from factory farms. Leather in fact has the greatest impact on eutrophication because the wastewater often flows untreated to local waterways.⁵

Tannery workers – including children as young as 10 in some countries – risk severe side- effects from exposure to these toxic substances. Acute effects include irritation to the mouth, airways and eyes; skin reactions; digestive problems, kidney or liver damage; long-term cancer and reproductive problems.⁶

Sustainable leather production

The Leather Working Group is a multi-stakeholder initiative involving brands, suppliers, manufacturers, NGOs and end users. It uses an audit protocol that assesses the environmental compliance and performance capabilities of tanners, and promotes sustainable environmental business practices within the leather industry.⁷

The LWG estimates that 20 per cent of all footwear leather is covered by their audits, which assess chemical, waste, water management and safety matters relating to tanneries. Around 42 brands as well as 36 suppliers, and many more tanneries, are LWG members. Alternative tanning methods exist – after all, leather was produced for centuries without heavy chemicals.

Textile Exchange are working on a Responsible Leather Assessment tool.

The luxury end of the market has seen a revival of the ancient technique of tanning with plant extracts. Bark, wood, berries, roots and leaves are used to colour and preserve the hides, producing far less harmful waste, and a biodegradable leather. It does however, take much longer than chemical processing.

The Tanners Extract Producers Federation (TEPF) is dedicated to spreading best practice among tanners to promote vegetable leather use for designers and consumers. It currently has 43 member organisations from the leather supplier sector.⁸

Novo Campo promotes sustainable practices on cattle ranches in the Amazon region contributing to reducing deforestation.

Alternatives to leather

Synthetic alternatives to leather have existed for several years – such as polyurethane (PU). While this scores better than leather on the Higg Index with lower scores for global warming and pollution, disposal of PU poses its own environmental problems. More sustainable solutions are in development from international chemicals groups – high-grade artificial leathers and suedes derived from recycled polyester and using non-toxic dyes, destined for use in apparel, footwear and accessories.

Natural alternatives being trialled for use in footwear and accessories include cork fabric from Mediterranean Cork Oak trees, bark fibre reinforced with polymers, and leather substitutes derived from pineapple, grapes, mushrooms and seaweed.

For more on sustainable alternatives, take a look at our Fabric Switch: Leather guide.