Fast Fashion's Carbon Footprint Can Be Cut by Changing Shipping and Wear Time, Study Finds

A new life-cycle study led by researchers at Concordia University in Montreal examined the environmental footprint of fast-fashion polyester and cotton T-shirts, tracing each garment from raw material and manufacturing in China, through shipping, to consumer use in Montreal and final disposal. The team wanted to identify which stage of a T-shirt's life caused the most environmental damage, and where the biggest cuts could be made.

Under the study's baseline scenario, polyester T-shirts produced substantially higher greenhouse gas emissions than cotton ones, because manufacturing synthetic fiber requires more energy and fossil fuels. Cotton T-shirts, meanwhile, placed far greater demands on land and water, reflecting the resources needed to grow the crop.

However, the researchers found that transportation and how long a garment is worn mattered more than the choice of material. Air freight was one of the largest single contributors to emissions; switching to sea freight cut a T-shirt's carbon footprint by roughly 30% to 60%, depending on the material. Doubling a garment's lifespan could cut emissions by about half, since fewer new garments would need to be produced to provide the same amount of wear.

The findings suggest the fashion industry could achieve its greatest environmental gains by making fewer garments, designing them to last longer, and cutting back on air freight. The researchers said that for consumers, simply wearing clothes for longer may deliver a bigger climate benefit than choosing between cotton and polyester.

The study, titled "From production to waste disposal: A life cycle assessment of fast fashion polyester and cotton T-shirts," was led by Xinyu Xu and colleagues and published in the journal Cleaner Waste Systems.