Cow Leather vs. Vegan Leather: What New Research Says About the Carbon Footprint
Is vegan leather actually better for the planet, or is that just marketing? It's a fair question - and until recently, the honest answer was that the data was patchy. That changed with a new peer-reviewed meta-analysis published in ACS Sustainable Chemistry & Engineering by researchers at Cornell University and New York University, which reassessed the carbon footprint of leather using global livestock data.
The headline finding: producing one kilogram of cow leather emits a global average of 187.1 kg of CO2 equivalent - more than 12 times the 14.9 kg average of vegan leather alternatives.
This post breaks down what the researchers measured, why the gap is so large, and what it means for anyone choosing between animal leather and plant-based alternatives. Every number below comes directly from the study.
The study at a glance
- What: "The Carbon Footprint of Leather: A Comprehensive Reassessment Using Global Livestock Data and Meta-Analysis"
- Who: Researchers at Cornell University and New York University
- Where: Published in ACS Sustainable Chemistry & Engineering, a peer-reviewed journal of the American Chemical Society
- Method: A meta-analysis combining global livestock data from the UN Food and Agriculture Organization (FAO/GLEAM) with published life-cycle assessments
- Key result: Cow leather averages 187.1 kg CO2 eq per kg of finished material; vegan leather alternatives average 14.9 kg CO2 eq per kg
What "kg CO2 eq" actually measures
The study measures each material's footprint in kilograms of carbon dioxide equivalent (kg CO2 eq) per kilogram of finished material, from "cradle to gate" - every emission from the birth of a cow (or the sourcing of raw polymers) to the moment finished material leaves the factory.
The "equivalent" part matters because not all greenhouse gases are the same. Cattle release methane through digestion, and methane traps far more heat than CO2 over time. Converting everything into CO2 equivalents puts different gases on a level playing field, so materials can be compared fairly.
The numbers, side by side
Here is how the material categories compare in the study, measured in kg CO2 eq per kg of finished material:
| Material | Carbon footprint (kg CO2 eq / kg) |
|---|---|
| Cow (bovine) leather - global mean | 187.1 (typical range 148.1–214.5) |
| Mycelium (mushroom) leather | 16.08–20.42 |
| Polyurethane (PU) leather | 6.06–21.94 |
| Plant-based / PU blend leather | 8.22 |
| All vegan alternatives - average | 14.9 |
The scale of the gap is hard to overstate. According to the study, even the most energy-intensive vegan leather has a footprint roughly 54% lower than the tanning phase of animal leather alone - before a single farming emission is counted.
Why cow leather's footprint is so high
The study splits animal leather production into two phases, and one of them dominates.
1. The farming phase
Raising cattle generates enormous methane emissions through enteric fermentation - the natural digestive process of cows. Using FAO global livestock data, the researchers put the global mean farming-phase footprint at 138.9 kg CO2 eq per kg of leather. That is roughly nine times the entire footprint of an average vegan alternative, from farm gate to factory gate.
2. The tanning phase
Turning raw hide into stable leather requires intensive chemical treatment and energy-hungry drying. The footprint here depends heavily on the local power grid: the study found tanning in India emits 165.11 kg CO2 eq and Turkey 140.36 kg CO2 eq, versus just 7.16 kg CO2 eq in Spain, where the energy mix is cleaner - a more than 20-fold difference for the same process.
"But isn't leather just a byproduct of meat?"
This is the most common defense of animal leather, and it's the one this research most directly challenges.
Many older European assessments assumed hides come from dairy cows and assigned just 0.42% of the animal's emissions to the hide - making leather look almost carbon-free. The Cornell and NYU researchers found this doesn't reflect global reality: most hides come from beef-focused herds, where the hide is a valuable co-product that slaughterhouses depend on for revenue. Using a global average economic allocation of 8.1%, the study concludes hides must carry a proportional share of farming's heavy climate impact.
In other words: hides are not "waste" being rescued. They are a product the livestock economy counts on - and their carbon cost is real. The study's authors found that once global data is used, conventional leather's emissions are far higher than earlier estimates suggested.
Where leather is made changes everything
One of the study's most striking findings is how much geography matters. Farming-phase footprints range from 207.5 kg CO2 eq in Central and South America (where beef-dominant herds drive the highest impact) and 168.2 in Sub-Saharan Africa, down to 101.09 in Western Europe and 46.6 in the Russian Federation. Since most consumers have no way of knowing where the hide in their bag was raised or tanned, the global averages are the honest benchmark - and the global average is 187.1.
Where plant-based blends fit in
Within the vegan category, the study highlights an important detail: not all alternatives perform the same. Plant-based/PU blend leathers - materials that replace a share of petroleum-derived polymer with renewable plant feedstocks - measured 8.22 kg CO2 eq per kg, among the lowest footprints of any category studied and about 22 times lower than the global average for cow leather.
This is the category our own material belongs to. O.N.E bags are made from a corn-based 40/60 hybrid leather: 40% bio-based polymer derived from corn, blended with microfiber for strength and longevity. We didn't choose it because of this study - the study simply confirms, with global data, the logic that led us here.
An honest footnote
No single number tells the whole story of a material. This study measures climate impact - it does not weigh factors like biodegradability, durability, or microplastics, where every material (animal and synthetic alike) has trade-offs worth scrutinizing. But on the question the study set out to answer - which material heats the planet more - the data is not close. A 12-fold gap doesn't shrink to zero under any reasonable assumption the researchers tested.
Why this matters to us
O.N.E began as a conventional leather goods brand. We transitioned to plant-based vegan leather because we believed a bag shouldn't cost the earth more than it gives back - that good design and lower impact aren't opposites, but partners. It's why we replaced animal hides with corn, lined our bags with recycled polyester suede, and kept asking our suppliers harder questions.
Research like this matters because it moves the conversation from beliefs to numbers. We'd encourage anyone - whether you ever buy from us or not - to read the study, check the data, and make your next purchase an informed one.
If you're curious how a field of corn becomes a carryable material, we've written about that journey in From Corn to Carry.
Frequently asked questions
Is vegan leather better for the environment than real leather?
On carbon emissions, yes - by a wide margin. A recent meta-analysis in ACS Sustainable Chemistry & Engineering found cow leather emits a global average of 187.1 kg CO2 eq per kg of material, versus 14.9 kg for the average vegan alternative - a more than 12-fold difference.
How much CO2 does leather production emit?
According to the study, producing 1 kg of finished cow leather emits 187.1 kg CO2 eq on average globally, with a typical range of 148.1–214.5 kg depending on region. Farming (mainly methane from cattle) accounts for 138.9 kg of that; tanning and finishing account for the rest.
Isn't leather a byproduct of the meat industry anyway?
The research challenges this. Hides are economic co-products, not waste - they carry a global average of 8.1% of the animal's market value, so the study assigns them a proportional share of farming emissions. Treating hides as "carbon-free waste" relies on dairy-herd assumptions that don't match where most of the world's leather actually comes from.
What is the lowest-carbon leather alternative?
In the study's comparison, plant-based/PU blend leathers had one of the lowest footprints measured, at 8.22 kg CO2 eq per kg - lower than the vegan average of 14.9, and about 22 times lower than cow leather's global mean.
What is corn leather?
Corn leather is a plant-based vegan leather made by converting corn starch into a bio-polymer, which is then blended with microfiber for durability. O.N.E uses a 40/60 corn hybrid - 40% bio-based corn polymer, 60% microfiber - which falls within the plant-based/PU blend category measured in the study.
Source: "The Carbon Footprint of Leather: A Comprehensive Reassessment Using Global Livestock Data and Meta-Analysis," ACS Sustainable Chemistry & Engineering (American Chemical Society). Read the study at pubs.acs.org/doi/10.1021/acssuschemeng.5c12631. All figures cited in this article are drawn from the published research.
