The climate case against beef is now almost boringly well-established: It is, by far, the most carbon-intensive food in the world, amounting to about 6 percent of all global greenhouse gas emissions. But cows don’t just become burgers and steaks. They also become shoes, bags, couches, and car interiors — products often marketed with a very different story about sustainability.
Leather has often been defended in the fashion industry as an essentially harmless by-product of meat production — a waste material that would otherwise be thrown in the trash. But if you think about it, that assumption is kind of weird: The global leather market is valued at hundreds of billions of dollars annually, and hides are an important revenue stream for cattle producers. We wouldn’t say that paper is a waste product of timber production just because the most valuable parts of the tree are used for lumber. Likewise, animal hides help support extra profits for cattle farming and also carry a share of that industry’s emissions and other planetary impacts.
A recent meta-analysis published in ACS Sustainable Chemistry & Engineering reveals that cow leather’s carbon footprint is much larger than we thought: 70 percent larger than previous estimates. Using the study’s emissions estimate, Vox calculated that a men’s leather wallet would carry the emissions equivalent of roughly four American-made beef burgers; a leather tote bag, meanwhile, might be comparable to roughly 35 burgers.
Pound for pound, the researchers estimate, bovine leather emits more than 12 times as much as vegan leathers made from materials ranging from synthetics like polyurethane — mass-market pleather — to next-generation fungi– and plant cellulose-based leathers.
Mikaila Roncevich, the study’s lead author and a graduate student in the department of fiber science and apparel design at Cornell University, cautioned me that there’s still some uncertainty in the precise numbers due to gaps in the data on global cattle and leather supply chains. But the core insight of the paper for consumers remains the same. “If [leather’s] footprint is shocking or seems high to people, I think it should be a push to keep reflecting on the impact of raising animals for products,” Roncevich said. Leather may benefit (along with wool and other animal-derived materials) from a natural image, but on closer examination, it helps sustain one of the world’s most polluting, environmentally destructive industries.
Why leather’s carbon footprint has been so underestimated
The climate impact of beef and other foods has been relatively well documented — and covered exhaustively in outlets like this one — thanks in part to a landmark 2018 paper that consolidated and compared data for about 40 of the world’s most popular agricultural goods. But “much less attention has been paid to impacts of textiles and materials that originate from [these] farms,” Matt Hayek, an associate professor in NYU’s department of environmental studies and a co-author of the ACS study, told me. With the new paper, the first peer-reviewed meta-analysis of leather’s overall greenhouse gas emissions, the researchers hope to help bring leather the same kind of scrutiny that’s been applied to the food system.
When one industry produces several different saleable products — such as the meat, hides, and other materials derived from cattle — researchers must decide how much of that industry’s emissions should be assigned to each product. There are multiple methods for doing this, but one common one is to use each co-product’s relative economic value. The new paper’s estimate for leather’s carbon footprint comes in so much higher than earlier estimates partly because of the authors’ more accurate global accounting of emissions attributable to animal hides.
Many previous studies of leather’s carbon footprint have relied on the EU’s environmental footprint accounting guidelines for leather, which assume that animal hides are responsible for a tiny share of the environmental burden of cattle farming. That is because, in Europe, dairy and meat production are closely intertwined, with most cattle herds being used for both milk and beef. The European guidelines that have informed many estimates of leather’s emissions recommend allocating 88 percent of cattle’s environmental impact to dairy, and 12 percent to all products coming from the slaughtered animal carcass, which includes mostly beef, but also hides. The downstream result is that hides are treated as responsible for just 0.42 percent of the animal’s total farming footprint — essentially a rounding error.
But that assumption travels poorly to other parts of the world, including the US and other top producers of bovine hides destined to become leather, where most cattle herds are not used for dairy. In Brazil, the world’s cattle-farming capital, only a small share of cattle are dairy animals. Most cattle there are raised for their beef and hides, and demand for leather from the US and other rich countries has helped drive deforestation in the Amazon rainforest, which gets cut down to make room for cattle rearing.
To correct for the “Eurocentric view” used in past research, as Roncevich called it, the team used data from the UN Food and Agriculture Organization to more accurately trace global cattle herds — accounting for differences between beef and dairy herds and calculating the emissions associated with them in different regions. To determine what share of those emissions should be assigned to leather, they then used estimates of the economic value of animal hides in different parts of the world. As a global weighted average, they found, bovine hides actually make up about 8.1 percent of the total value of the animal at slaughter.
That might not sound very high, but, the authors argue, it’s significant enough to meaningfully shape the cattle industry. “Leather is a valuable co-product that impacts decisions during the cow’s lifetime,” Roncevich said. Farmers bring animals into the world according to demand for their products — and consumer demand for leather likely means that global cattle herds are larger than they would be otherwise.
I consulted agricultural economist Richard Sexton, an emeritus professor at UC Davis, for his thoughts on that analysis. The 8.1 percent economic allocation to cattle hides “sounds roughly right,” he told me in an email, but he’s skeptical that even a collapse in demand for leather would have a major impact on global cattle populations. He predicts that such a scenario would result in “a new equilibrium with a somewhat smaller herd size and slaughter volume, but nothing drastic or extreme.”
What comes after leather?
Beyond the wonky questions about carbon accounting, this research taps into a more visceral debate in the fashion world and our broader culture: the pervasive assumption that what comes from nature must be better for nature. But what seems natural is not necessarily good.
That message is often especially anathema in fashion media and influencer circles, where natural fibers, including animal-based ones, are widely extolled. “There’s definitely such a gut reaction that people have when they hear the terms ‘natural’ versus ‘synthetic,’” said Roncevich, who is also a designer of accessories made with animal-free materials. (Of course, there is little that’s natural about cattle ranching or preserving animal skins so that they don’t readily biodegrade.)
Many shoppers believe animal leather is more durable than synthetic alternatives, which could partially offset its much higher carbon footprint if it means people need to replace shoes, bags, or jackets less frequently. That can be true, particularly when the synthetic leathers most readily available to consumers are the cheap, thin kind that can crack and peel after relatively little use. There is also concern about the damage of introducing more plastics-based products into the environment. But the reality is far more complicated than a clean quality binary between slaughter-based and synthetic leather (the former can fall apart, too, and is often made more durable with plastic-based finishes). Animal leather has plenty of toxic baggage of its own, from the chromium salts and other pollutants generated by tanneries to the manure runoff and water pollution associated with cattle ranching.
All of the non-animal leathers evaluated in the meta-analysis had a much lower carbon footprint than bovine leather — and the category is no longer limited to fossil fuel-derived pleathers. Startups are now developing leather-like materials from mycelium, cactus, pineapple leaves, apple pomace, and other bio-based materials. But for these materials to become more than niche alternatives and scale affordably, they’ll need continued innovation.
I suspect people’s feelings about natural and synthetic materials have less to do with a rational weighing of impacts than about the cultural meanings and class signals attached to them. But those signifiers aren’t immutable. Some large companies like Apple have started to ditch animal-derived leather materials, and the study’s authors call for more brands to invest in bio-based leather alternatives. For that to succeed will demand a bit more of us as consumers, too: to be a little more open-minded about what vegan leathers can be, and more clear-eyed about the harms of the real thing.
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