Until the rise of online retail, you might have been forgiven for thinking that all apparel was shipped in burlap sacks. Those wanting their garment spending to be sustainable these days can take comfort in reusable wooden hangers, paper shopping bags, and recycled fibres. The only glimpse of plastic in many fashion stores is the electronic equipment at the checkout.

Below that surface, however, the fashion industry is built on a mountain of artificial textiles. Global production of cotton and wool has barely increased since the early 1990s. Manufactured and synthetic fibres such as viscose, nylon and, above all, polyester have roughly trebled.