A new research paper challenges the assumption that natural fibers biodegrade quickly, finding cotton dominating 150-year-old sediments in Rudyard Lake, Staffordshire, UK. Co-authored by Carry Somers of Fashion Revolution, the iScience study urges the fashion industry to base sustainability claims on science. It highlights ongoing debates between natural and synthetic fiber impacts.
Researchers examining sediments from Rudyard Lake in Staffordshire, UK—a site historically fed by textile mills—discovered that natural fibers, particularly cotton comprising over 70% of the 150-year fiber record, outnumbered synthetics even after polyester appeared in 1979. The paper, published in iScience and co-authored by Fashion Revolution co-founder Carry Somers, academic, and citizen scientists, questions fashion's reliance on natural fibers as biodegradable alternatives to synthetics, which hold 69% of the global fiber market and contribute 35% of ocean microplastics per IUCN estimates. Majority fibers in global seawater samples are also natural, persisting in environments like low-oxygen lake beds, penguin habitats in South Georgia, and UK rivers. This challenges assumptions amid campaigns promoting natural materials over plastic-shedding synthetics found ubiquitously from soils to sea spray. Somers stated, “We have to get away from this extreme that if plastics are bad, natural [fibers] must be good.” Dr. Thomas Stanton, a co-author, noted that in low-oxygen conditions, natural fibers can persist over ecologically meaningful timescales, though not denying eventual biodegradation. Deirdre McKay, another co-author, remarked, “Fashion is participating in a giant, uncontrolled experiment with ecology.” The study critiques the Product Environmental Footprint (PEF) methodology, which deems synthetics lower-impact than cotton in water use, land, pesticides, and durability—a view contested by over 900 signatories representing 500,000 farmers in 2024 and a 2026 Bremen Cotton Exchange paper. An EU Green Claims Directive aims to curb greenwashing but may favor synthetics, per critics. Brands like Anya Hindmarch and Pangaia test materials for biodegradability under ISO standards, emphasizing product-level verification over visual fragmentation tests. Asha Singhal highlighted that biodegradation depends on ecosystem factors like microbes and moisture.