The world of fashion is synonymous with change. Recent trends suggest that the industry itself is in the throes of change, the latest victim being fast fashion chain Forever 21. At one level, its filing for bankruptcy protection is the result of the impact of online shopping on brick-and-mortar shops. The so-called "retail apocalypse" has hurt companies as diverse as New Look, L.K. Bennett and Marks and Spencer. But there is more to it than online competition and high rentals. There are early signs that fashion is having to confront its "Greta Thunberg" moment as environmental concerns associated with the teenage climate change activist intrude increasingly into the consciousness of consumers and how they choose to spend their money.

The sustainability debate has made its way into fashion bible Vogue. It has led to a mock funeral and "die in" protests by climate activists during last month's London Fashion Week. It has also spurred the rise of designer tog rentals as well as resale sites and apps such as Depop, Thredup and Poshmark that allow consumers to buy second-hand clothing. For Gen Z - those born after 1997 - the environmental impact of what they buy matters, according to research by Ernst and Young. Millennials are not unaware of green issues but these have less sway on what they buy. Now mostly in their teens, Gen Z's influence will only rise as they grow into adulthood and have greater purchasing power. This will have an impact on the retail landscape.