It produces a slush of chemicals and gases, including carcinogenic chromium (IV). Hides are doused in drums of water, chromium salts and tanning liquor to stop them decomposing and to give a supple, colour-fast leather. Tanning is the most toxic phase in leather processing, with a high percentage of production still using chromium tanning. 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. 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. High environmental costsĪs currently practised, leather production is linked to some serious sustainability issues, not least as a by-product of the meat industry. 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. 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. 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

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. 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. Most leather comes from bovine animals – chiefly cows, but also sheep and goats.

Manufacturers then turn this into footwear – the primary use – as well as clothing, fashion accessories, interiors and car upholstery. 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. Demand for leather goods is growing – but so is criticism of its severe environmental impact, which is driving a keen interest in sustainable alternatives. Probably the most ancient fabric used by humans, leather is a multi-billion dollar global industry.

Chemistrry of animal hides