As Stella McCartney launches cinnamon-scented, compostable sneakers, she also throws her support behind The Nat, a global initiative to close the $710 billion nature funding gap.
The sneaker smells like cinnamon. That’s the first thing Stella McCartney wants you to know. “I mean this is insane,” she said in a statement. “My shoe designer came up to me and said, ‘smell the sole’. It’s made of cinnamon waste. It smells of cinnamon! And it’s basically 100 percent plant-based, recyclable, and biodegradable textile. It’s a closed-loop production, so it ensures completely zero waste. It is mind-blowing.”
The S-Wave Sport Trainer, released globally as part of McCartney’s Autumn 2025 collection, might be her most poetic mic-drop yet. Designed in partnership with Israeli materials startup Balena, the shoe’s sole features BioCir Flex, a biobased, compostable, and recyclable alternative to the petroleum-based TPU and rubber that dominate performance footwear. Its shock-absorbent, motion-responsive properties are the result of a multi-year R&D cycle engineered for circularity. And yes, it smells like cinnamon — naturally dyed using food waste byproduct.
The launch arrives just days after McCartney made headlines for a different kind of step: her backing of The Nat, a new cultural platform attempting to help close the $710 billion global nature finance gap. Structured like a philanthropic think tank meets Hollywood gala circuit, The Nat is designed to reroute private capital into underfunded ecological initiatives while using the tools of celebrity and pop culture to normalize nature as a cultural asset.
It is an audacious double play for McCartney, who has long occupied the rarefied space between art and advocacy. Now, she’s not just designing for the future — she’s financing it, too.
Funding nature like it’s art
Unveiled during London Climate Action Week in June 2025, The Nat seeks to raise awareness and investment for global restoration efforts in the most culturally relevant way possible: through the shared language of fashion, film, music, and design.
McCartney is joined in this effort by a constellation of public figures — Sir David Attenborough, Harrison Ford, Sabrina Elba, Wanjira Mathai, and Conservation International CEO M. Sanjayan, to name a few. They will all serve as founding stewards of the platform. The group’s first marquee event, the NAT Gala, is set for September 9 in New York City, coinciding with the UN General Assembly.
Organizers say the goal is to shift environmental fundraising from niche to necessary. Gail Gallie, co-founder of The Nat, said in a statement: “This is a first-of-its-kind celebration of nature that combines the creative forces of art, fashion, film, food, and music… to ensure that nature receives the significant funding it desperately needs.”
According to the Paulson Institute, the World Bank, and The Nature Conservancy, closing the nature finance gap will require at least $700 billion annually — most of it from private and philanthropic sectors. The current shortfall has left countless conservation projects stranded without capital, despite their proven social and ecological benefits.
That is where McCartney fits in. While others raise capital for tree-planting or coral reef restoration, she’s been modeling what it looks like to design with nature at the core — long before it became fashionable.
Fashion’s next material
Circularity is not a new buzzword in McCartney’s atelier. For two decades, the brand has pioneered cruelty-free luxury, operating under a mandate to never use leather, feathers, fur, or skins. But the S-Wave Sport Trainer marks a radical new benchmark in product innovation: a fully closed-loop material that can be composted or remanufactured at end of life.
Developed by Balena, BioCir Flex is a thermoplastic elastomer made from natural ingredients that mimics the performance profile of synthetic polymers. What sets it apart is not only its compostability but its blendability — brands can use it in place of conventional plastic across footwear, accessories, or soft goods. Balena claims it performs on par with standard TPU, but without petrochemical content or industrial toxicity.
The Tel Aviv-based startup, led by founder David Roubach, is one of a growing class of biotech firms turning waste streams into premium materials. In an interview earlier this year, Roubach described Balena’s mission as “building infrastructure for circular fashion.” He has argued that if compostable materials don’t have scalable systems to process them at end of life, the sustainability label is just marketing. Balena’s goal is to change that.
The company made its initial public debut with a pair of fully compostable slides in 2022, which were only industrially compostable in Balena’s own facilities. Since then, it has worked to expand its pipeline of pilot partners, including Stella McCartney.
The S-Wave Trainer’s design reads like a manifesto in motion. The sole is constructed from BioCir Flex, dyed with cinnamon waste, and designed to absorb shock while remaining pliable and responsive. The upper is made with recycled polyester, another nod to McCartney’s consistent push to eliminate virgin synthetics wherever possible.
While circular sneaker designs have begun trickling into the mainstream — Adidas, Allbirds, and On have all launched versions of fully recyclable or compostable shoes — none have married biotech precision with luxury cachet quite like this. For McCartney, it’s not just a fashion item. It’s an invitation to rethink value.
“This collaboration represents more than just a partnership, it’s a shared commitment to shaping a future where materials are truly circular, sustainable, and high-performance,” Roubach said in a statement. “Stella has long been a beacon of responsibility and innovation in fashion, and we’re proud to help push the industry forward together.”
“I think that’s really where it becomes sexy — where you’re not just providing an alternative,” McCartney told Vogue. “You’re creating a great product. At the end of the day, I’m a designer — I’m not trying to be a politician.”
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