“Sustain” implies the continuation of some status quo. For a planet that has sustained life for billions of years, a century or two is a mere instant, but the usual time scale of sustainable thinking is only in years or decades. Life in the early 21st century, with a global population of 7 billion and a major reliance on non-renewable energy and raw materials is not sustainable. Many developments described as sustainable are well meant, but while they may be a step in the right direction, they do not lead to a world that can sustain itself for hundreds of years to come. The basic resources are available: the earth receives the same energy from the sun in one minute that humans use in a year. Nature produces 130 billion tons of cellulose per year, using water, sunlight and carbon dioxide as primary ingredients. The average human being consumes more than 10kg fiber per year. The future of textiles and fashion will involve efficiently produced natural fibers that share agricultural land with food crops, synthetic fibers that are either oil-based and continually recycled, or that rely on a future chemical industry with renewable resources as a feedstock. How easily can we get there from here?