Humans have been using sheep’s wool to keep warm for thousands of years. But there is a darker side to the material.
Wool — the fluff of sheep — is perfect for keeping cozy, as the pockets of air in the fibers trap heat, making it an effective insulator in the colder months. But nowadays, most wool doesn’t come from free-roaming sheep who spend their days out grazing on vast green fields. Most of the millions of sheep raised annually for wool live on industrialized factory farms. These facilities subject the animals to cramped and dirty conditions, but they’re also terrible for the environment.
Part of the issue with wool is that sheep are hungry animals. They consume around one kilogram of grass dry matter every day. When they’re not asleep, they’re usually eating. This is fair enough for the sheep, but it’s not that great for the planet. This is because, like cows, sheep are ruminant animals, and this means they have a fore-stomach full of microbes called methanogens. So, when sheep belch, they produce methane, a potent greenhouse gas with 80 times the warming power of carbon dioxide.
On average, one sheep will emit around 13 kilograms of methane per year. And when you consider there are more than 1 billion of them on the planet, mostly farmed for meat or wool, this all adds up to a catastrophic amount of emissions.
But greenhouse gases aren’t the only environmental issue associated with sheep farming. In New Zealand, which is one of the world’s biggest wool producers, 99 percent of the rivers running through urban and farm areas are heavily polluted. A lot of this is due to dairy farming, but according to Wool Facts, a resource run by PETA Australia, much of the blame can also be attributed to sheep.
This is because sheep feces contain high amounts of E.coli, a strain of bacteria that, in some cases, can cause disease. This means that rivers near farms are not safe to drink from or swim in. In 2019, one poll conducted on behalf of Fish & Game New Zealand found that water pollution was a top concern for more than 80 percent of New Zealanders.
“Kiwis are extremely worried that they are losing their ability to swim, fish, and gather food from their rivers, lakes, and streams,” said Martin Taylor, chief executive of Fish & Game New Zealand. “People see those activities as their birthright but over the last 20 years, that right is being lost because the level of pollution in waterways has increased as farming intensifies.”
But this isn’t the only water-related issue with farming. Animal agriculture is also linked to an increase in ocean dead zones. These occur when fertilizers and nutrients run off into waterways, causing algae, which die off and deplete the ocean of its oxygen. This creates large areas of the ocean where nothing can survive. Industrial activities are also linked with dead zones, and there are currently more than 400 around the world.
Creating sustainable wool
The future of fashion must find solutions. And changing the way we produce wool is a key part of that, according to PETA (People for the Ethical Treatment of Animals). It’s why PETA, the largest animal rights organization in the world, is trying to change the wool industry forever.
In 2022, PETA launched a $1 million vegan wool prize fund to award the money to any individual or small business that could develop a functional, sophisticated, sustainable, warm, animal-free alternative to wool. The fabric also needed to be scalable and appealing to designers.
The animal rights organization says warm, cozy fibers don’t have to come from sheep. In 2018, PETA awarded a group of Colombian students for creating Woocoa, a bio-based hemp and coconut wool. That year, the challenge was sponsored by the luxury label Stella McCartney.
Is recycled wool a circular solution?
While animal-free fibers are gaining ground, recycled wool has also emerged as a promising middle ground for reducing the industry’s impact. Rather than relying on the resource-heavy process of raising and shearing new sheep, recycled wool gives discarded garments and post-industrial fabric waste a second life. The process involves collecting, sorting, cleaning, and respinning old wool into new yarn — dramatically lowering the demand for virgin fiber.
Using recycled wool can cut carbon emissions by as much as 75 percent compared to conventional wool. It also conserves water and prevents millions of pounds of textile waste from ending up in landfills each year. In Prato, Italy — a historic hub for wool recycling — some mills have been practicing this closed-loop process for more than a century. Modern brands are now looking to these heritage recyclers to reimagine circularity at scale, proving that warmth and sustainability can coexist without compromise.
Several fashion labels have already embraced recycled wool and plant-based fibers to reduce their environmental footprint. Stella McCartney continues to pioneer cruelty-free textiles, integrating regenerative cotton alongside vegan wool research. Patagonia uses recycled wool in its outdoor apparel, sourcing from certified partners that ensure full traceability and minimal waste.
Meanwhile, luxury label Eileen Fisher repurposes post-consumer garments through its Renew program, reworking old wool pieces into new collections. Danish brand Ganni has also experimented with recycled wool blends in its knitwear, pairing them with low-impact dyes and traceable supply chains. For fully vegan alternatives, brands like Pangaia are exploring bio-based fibers derived from agricultural waste, and Nanushka’s Okobor material mimics wool’s softness using recycled polyester and viscose.
PETA’s executive vice president Tracy Reiman has confidence in today’s designers’ abilities to produce a sustainable, ethical, scalable alternative to wool. “From apples and hemp to kombucha tea and cacti, there seems to be no limit to what designers can use to create wonderful, animal-free clothing and accessories,” she said. “PETA is delighted to offer innovative minds a big boost that will protect sheep, push fashion forward and help stop the environmental degradation caused by animal agriculture.”
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