We are well aware now that the continually rising consumption of red meat is hurting our planet. In a 2018 paper published in Science, zoologist Joseph Poore and agriculture researcher Thomas Nemecek offered up the largest dataset yet on the impact of farming on our planet. They found that every 100 grams of beef protein results in up to 105 kilograms of greenhouse gas emissions (a similar amount of tofu, for comparison results less than 3.5 kg of emissions).

Cattle ranching has an enormous impact on both our climate and biodiversity. Some 80 percent of deforestation and destruction in the Amazon Rainforest, for example, is tied to the industry, according to Yale’s Global Forest Atlas. Such studies continue to point to the conclusion that avoiding meat and dairy might be, as Poore told The Guardian, “the single biggest way to reduce your impact on planet Earth.”

But raising cattle isn’t all about beef. What about the leather made from the skin of those same cows?

Brazil, for instance, is not only the world’s most significant beef exporter but also the third largest bovine skin exporter. The impact of cattle farming around the world — not only in the Amazon — is about more than burgers. Demand for leather used to make bags, shoes, wallets, jackets and other accessories drive the cattle industry as well, yet these materials often escape the kind of public scrutiny beef consumption receives.

Perhaps the main reason that the fashion industry’s use of leather is less scrutinized is the byproduct myth. Leather industry funded initiatives like Nothing to Hide perpetuate the notion that global leather production is simply a byproduct of the meat industry. Such messaging makes the argument that leather is not worth very much but used for the sake of sustainability, and goes so far as to call leather “recycled” for this reason.

In reality, leather is a co-product — and a valuable one too, set to be worth over $128 billion by next year. For individual abattoirs, a reduction in cattle skin sales might mean multi-million dollar losses. In the dairy industry, newborn male bobby calves are considered a “waste product” because they cannot produce milk, but their soft, “valuable hides” offer the “livestock” industry an additional stream of income. Demand for leather, in fact, increases the number of cattle reared across the world.

Some fashion brands claim environmental sustainability by seeking cow skin leather that is tanned differently, with vegetable tannins, for example, or without the use of toxic chemicals and heavy metals like formaldehyde and chromium. While these chemicals can have a devastating impact on communities and ecosystems surrounding tanneries, The Sustainable Apparel Coalition’s Higg Material Sustainability Index (MSI) data points to the cattle rearing itself as the most damaging.

So what is the impact of leather production compared to beef or dairy production? The MSI tool shows that from cradle to gate, cow skin leather production has the third most significant impact (after alpaca wool and silk) when considering its contribution to global warming, eutrophication, water scarcity, and resource depletion (fossil fuels). By these factors, even synthetic polyurethane leather has just a fraction of the impact of real cow skin leather — a seemingly counterintuitive reality.

It can be difficult, however, to isolate and measure the impact of leather from that of the beef industry. Sheila Estaniel, Sustainable Apparel Coalition’s director of communications, says that the measured impacts of raising the cow (methane burps, feed production, and so on) are split between the value of the meat and the cow hides. “While most of the cattle raising impacts are attributed to the meat, there’s still a portion that is attributed to the cow hides used for leather,” she says. “The life cycle impact results for leather can therefore be very different depending on the amount of impact allocated to the hides.”

The Higg MSI uses an “economic allocation,” or, is looking at the value of the meat versus the value of the hides, to determine leather production impact. According to Estaniel, it’s significant that even when using an economic allocation, leather still has a serious impact.

This might all still be a little abstract, lacking concrete examples of just how harmful, say, a leather boot can be, compared to a beef burger. Digging deeper, the United Nations Industrial Development Organization’s Leather Panel compiled data that breaks down the allocated emissions between cow skin and meat, finds that every square meter of cow skin leather produced, results in about 110 kilograms of carbon dioxide emissions. Using this data, Collective Fashion Justice calculated that an average leather tote bag has the carbon equivalent of charging 12,164 smart phones, with a leather jacket sitting at a whopping 176 kg of emissions, equal to burning 195 pounds of coal.

These numbers are significant, but, as with beef, cow skin leather’s impact stretches beyond carbon emissions. The material has an enormous water footprint. According to Collective Fashion Justice’s CIRCUMFAUNA initiative, a typical cow skin leather shoe has a water footprint of over 7,600 liters. The calculation, based on UNESCO-IHE data and verified by Faunalytics, also found that one cow skin leather bag uses the amount of water one person drinks in more than 23 years.

If you’re wondering why cow skin leather has such a significant water footprint, environmental researcher and co-founder of Plant Based Data, Nicholas Carter, says that “cattle based products have such a high water footprint because they’re 1200+ pound mammals” and need to be fed a lot. Most of the water footprint of cattle, nearly 98 percent according to some estimates, is from water used to grow feed for the animals. Contrary to what one might assume, drinking water, service water, and other water use accounts for only about 2 percent of that footprint.

A recent study in Nature Sustainability considers not only the emissions associated with raising cattle but also the lost opportunity for carbon sequestration which comes with raising animals for production. Enormous swathes of land around the world are planted with monoculture crops fed to farmed animals — land that would otherwise be sequestering 99 to 163 percent of our carbon budget. While this study is framed around food, such findings pertain at least significantly, if not totally, to fashion as well. If we look at leather shoes with this in mind, their environmental impact can be considerable.

Both the food and fashion industries must take responsibility for their impact on the environment and consider actions to reduce that impact, ideally by making a just transition toward manufacturing and using recycled, plant-based, lab-grown, and bio-based foods and materials.

Fortunately, as scientists and designers continue to recognize the environmental and ethical reasons to avoid leather, change is being made. “We are in the midst of an industrial revolution where waste-diverted, recycled, biosynthetic, organic, and other visionary innovations are increasingly available,” says Joshua Katcher, author of Fashion Animals and Collective Fashion Justice board member.

Katcher mentions “circumfaunal materials,” which are materials that bypass the need for animals used in fashion. Some of these leather alternative materials include partially bio-based materials like Desserto made from cacti, lab-grown materials like Mylo, and material the resembles the look of leather made from mangoes and other fruits headed to landfill. This last example can be highly waste reducing, given 45 percent of all fruits and vegetables grown globally are discarded. While the fashion industry lags behind the food industry in its adaption to the need for non-animal solutions, the pace at which these materials are being developed is picking up. This is good news for the growing population of more environmentally and ethically aware shoppers, with Lyst’s 2020 Conscious Fashion Report revealing that since the start of 2020, searches for “vegan leather” increased by 69 percent.

Fashion isn’t always taken seriously; it’s often considered frivolous and unimportant. Yet fashion is not only a mode of expression and creativity but a serious contributor to some of the greatest environmental and ethical problems of our time. Leather is made in a supply chain that harms the planet, hurts and kills animals, and sees people forced into labor. Whether or not we care about fashion, and regardless of if we plan on buying some kind of “leather” any time soon, it would be a mistake to allow the current discussion around animal agriculture, climate, deforestation, water-scarcity and environmental justice to focus on burgers but not bags.