Too Hot for Knitwear: Climate Crisis, Biodiversity and Fashion Brands Using Wool and Synthetics


Read the full report by the Center for Biological Diversity and Collective Fashion Justice's CIRCUMFAUNA Initiative.


Executive Summary

Wool and synthetic fibers are responsible for serious harms to the planet, particularly the climate and biodiversity, yet they continue to be widely used in the fashion industry. While virgin synthetics are commonly recognized as an unsustainable material due to their fossil fuel origin, wool is often posited as the natural, eco-friendly alternative. However, wool is not a fiber simply provided by nature — it’s a scaled product of modern industrial, chemical, ecological and genetic intervention that’s a significant contributor to the climate crisis, land degradation, water use, pollution and biodiversity loss. Furthermore, many wool fibers are blended with synthetics, compromising their capacity to biodegrade. Wool can also be dyed and processed with chemicals that render the fiber non-biodegradable and create toxic pollution, but brands are not transparent with information relating to wool processing.


Although the connection between synthetics and microfiber pollution is well established, many companies rely on recycled synthetics — which have some benefits over virgin, but still shed microfibers — as their core sustainable materials sourcing strategy. Wool and wool blend garments continue to be promoted as responsible and sustainable, while investment in genuine solutions and more future-proofed materials is lagging. 


The Center for Biological Diversity and Collective Fashion Justice analyzed the Fall 2022 online catalogs of 13 top brands for the materials used in their knitwear and the information provided on the sustainability of those materials.

Key Findings:

  • More than half (55%) of the wool items in our analysis were blended with synthetic fibers derived from fossil fuels. That’s almost twice as many items as were 100% wool and 3 times more than those blended with animal and/or plant-based fibers.
  • Only 19% of all analyzed knitwear contained reduced impact fibers, with the vast majority of these made of recycled synthetics that still cause environmental harm. Very little use of sustainable materials was found.
  • High street brands were more than twice as likely to use synthetics in wool knitwear and 26 times more likely to offer 100% synthetic knitwear, though more than one-third (36%) of analyzed luxury knitwear used synthetics.
  • While some brands had initiatives to reduce the use of hazardous chemicals, none provided information about chemicals and dyes used in wool processing that could affect the garment’s end-of-life toxicity and biodegradability.
  • Despite the availability of sustainable fibers that can meet the quality, aesthetic and performance needs of knitwear, nearly 90% of analyzed items used virgin wool, which comes with a high environmental cost, not to mention serious animal protection issues.

Key Recommendations:

  • Brands must take steps toward a just transition by setting specific targets to move beyond the use of virgin synthetics and wool.
  • Environmental commitments and sustainability language must account for the impacts of synthetic and wool production, as well as the use of blended materials.
  • The fashion industry should ramp up its efforts to create clear definitions and standards for sustainability claims to prevent greenwashing.
  • Brands and the fashion industry should increase transparency around the chemicals and dyes used in processing wool fiber.
  • Brands and the fashion industry must invest in producing fewer overall items and increasing the use of sustainable alternative materials derived from bio-based, recycled and plant-based sources.

The climate crisis is being exacerbated by fashion’s use of fossil fuels for synthetics and its significant methane emissions tied to wool production. Climate change is a major driver of the wildlife extinction crisis, along with inefficient land use and other threats to biodiversity by the wool industry. While transformation cannot occur overnight, it’s imperative that the fashion industry recognize the need to move beyond the use of both conventional synthetics and wool and toward more responsible fossil fuel and animal-free alternatives.