Leather is a controversial material, and not just because cows have to die to produce it. Or because tanning leather requires toxic chemicals like chromium, which is sometimes dumped straight into local waterways. No, the worst part about leather, according to environmental activists, is that it’s a major contributor to climate change.
Animal agriculture is estimated to be responsible for 14.5 percent of the world’s greenhouse gas emissions. Kering, the luxury fashion conglomerate that owns such storied leather-loving brands as Gucci and Yves Saint Laurent, said in its 2020 environmental report that the production and processing of leather is by far the biggest contributor to its carbon footprint. And when the Amazon was on fire in 2019, the blazes were blamed at least partially on cattle ranching operations, and several large brands including H&M and Timberland vowed to stop sourcing leather from the region.
The alternatives available to the fashion industry, however—fossil-fuel-based polyurethane and PVC—leave something to be desired. All of the buzzy plant-based vegan leathers, whose manufacturers claim emit fewer greenhouse gases during production, are also mixed with synthetic petroleum products, making them more harmful than their “cruelty-free” marketing implies. With all the press around prototype products from Adidas and Stella McCartney, you would be forgiven for thinking you could already buy a lab-grown leather wallet or mushroom leather Stan Smith sneakers, but those materials are still struggling toward commercial viability.
For now, there is only one truly innovative and eco-friendly vegan “leather” that you can click to buy straight off the internet. AirCarbon, a carbon-negative material that is made using methane-munching marine organisms, hit the market a year ago in the form of sunglasses, wallets, and laptop and phone sleeves.
In an industry known for hyping even the most mundane of product drops (another recycled water bottle jacket, anyone?), the reception for the new brand, called Covalent, was surprisingly muted. That could perhaps be attributed to the CEO of the startup making AirCarbon, Newlight Technologies’ Mark Herrema, who brought the chillest of California vibes to our interview. When I noted his relaxed manner, he chuckled and pointed out that he’s been working on creating this material for a full 18 years. And anyway, with six rounds of funding under his belt, the latest one for $45 million, he’s well past the hype stage and into the “just do it” stage.
Literally: In August, Newlight announced a partnership with Nike to explore uses for AirCarbon. Nike, which says 70 percent of its emissions are wrapped up in its materials, is one of many large fashion brands that have committed to reducing its greenhouse gas emissions by at least 30 percent by 2030.
Herrema said the idea that would eventually lead to AirCarbon came to him while he was at Princeton in the early 2000s. He was studying politics, but some digestive issues drove him to start researching diets and the food system. He found out that a cow can burp up to 500 liters of methane, an extremely potent greenhouse gas, into the atmosphere every day. He imagined the market value of that methane—more than $20,000 per year from a large farm—evaporating into the air, and saw a business opportunity.
As it turns out, a hundred years earlier, scientists had discovered that there are organisms that eat greenhouse gases and store that energy inside their cells in the form of a molecule called polyhydroxybutyrate, or PHB. “And this molecule, when you isolate it, it turns out that it's meltable,” Herrema says. That means it can be molded into all types of materials in any color, from leather-like sheets, to fibers, and solid shapes like sunglasses.
Yep, PHB is a type of plastic. But a biodegradable and completely non-toxic plastic that’s made from organisms instead of fossil fuels.
Herrema convinced his friend Kenton Kimmel, who was studying bioengineering at Northwestern, to found Newlight Technologies with him in 2003. It took them ten years of work in an Orange County, California car garage to figure out technology, and another seven years to raise funding to build a manufacturing plant to produce the carbon-negative polymer at scale.
The Huntington Beach, California factory, which opened in September 2020, has giant stainless steel tanks filled with salty water and a mix of microorganisms called methanotrophs. Methane gas is blended into the water, and the organisms eat it to produce PHB, which is then harvested, purified, and refined into a white powder: AirCarbon. “We're mimicking a process that happens in nature every day,” Herrema says. That powder can then be mixed and melted into different products, including biodegradable forks and eco-friendly resin for eyewear.
Newlight Technologies isn’t the only company that has turned greenhouse gas-eating organisms into tiny polymer-making machines. San Francisco’s Mango Materials creates a variety of biodegradable polymers, including textiles, out of waste methane from a sewage treatment plant. “There are multiple companies in this space, which I think is the most exciting aspect,” says Lisa Y. Stein, a microbial physiology researcher at the University of Alberta. “It does demonstrate that this really is a viable technology for reducing greenhouse gases.”
Newlight isn’t just selling the polymer to manufacturers, however, but creating the end consumer products out of it. In addition to Covalent’s fashion products, Newlight also sells biodegradable straws and cutlery under the brand name Restore Foodware.
Each Covalent product is embossed with a time and date stamp which corresponds to the moment its material was created by the microorganisms. The code feeds into a blockchain-supported ledger detailing all the steps in the manufacturing process in between the stainless steel vats and it arriving to your door.
When I input the “Carbon Date” etched on a pair of Covalent sunglasses into the Covalent website, it told me that a third-party certifier had confirmed the glasses captured 2.03 kilograms of carbon dioxide equivalent gases (CO2e), even including the emissions from its global journey. The PHB was harvested close to midnight on September 7, 2019 in California, purified and dried into a white powder on September 8, combined with natural and synthetic materials to create a resin on September 17, and turned into sunglasses in an Italian factory on September 25 before getting shipped back stateside in December. It was messengered to my apartment almost two years later. The sunglasses, which sell for $150, are matte black, flexible, lightweight, and strong. The leather material in the Covalent iPhone sleeve, also matte black and supple, feels expensive (though not really like leather). My husband, an architect who spends his days designing the sleek interiors of modern vacation homes and boutique hotels, practically snatched the sunglasses out of my hands when I unpacked them.
Unlike the straws and cutlery Newlight is providing to Shake Shack and selling in Target stores, AirCarbon fashion materials aren’t biodegradable or FDA-certified non-toxic. (Though there's no evidence that these materials have worrisome substances added.) The sunglass resin is 78 percent PHB, while the leather material is 51 percent PHB, the rest being natural and synthetic rubber, pigment, and processing aids. The company is working on sourcing a biodegradable alternative to the synthetic rubber, but its main focus for now is carbon capture. Eventually, the team wants to build up a take-back and recycling program for Covalent products—and track the climate impact of that too. But like all polymers, AirCarbon loses some quality every time it's reprocessed, so that can only be done a few times before it too will end up in the landfill and release its methane back into the environment.
For these reasons, Stein says carbon-negative fashion will be one small part of the fight to stop runaway greenhouse gas emissions. Even though Herrema was inspired by belching cows, you can’t easily capture bovine burps, or the methane about to be released en masse from melting permafrost. You need a point source, like a wastewater treatment plant or landfill.
Similar to how you might pay for wind power from your local electricity provider, even though the electrons themselves are from the nearest coal plant, Newlight pays for methane to be captured from abandoned coal mines and put into the natural gas grid, while sourcing its own methane from the local natural gas provider. “Moving ahead, we plan to source methane and carbon dioxide from farms, landfills, food waste digesters, abandoned coal mines, ethanol plants, and direct air capture plants,” Herrema said by email.
But getting the material from microorganisms instead of petroleum represents a win in the end, says Stein, “even though it's not necessarily a huge dent in the overall methane budget.”
One thing is for sure, the public is tired of feeling guilty about every accessory they buy.
“I think people do actually care about more sustainable products,” Herrema says. “The challenge has been matching the demand or the care for more sustainable products with real options.” In a fashion industry rife with greenwashing and overpromises, the fact that you can hold this carbon storage technology in your hands is a welcome change.
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