Snow machines are a reliable way to top up the slopes when the weather won’t cooperate, but they have a few environmentally unfriendly side effects. First, they’re highly energy-intensive, and they require large amounts of water – covering the 23,800 hectares of Alpine ski slope for one season requires 95 billion litres of water, the annual water consumption of a town of 1.5 million people, which can interfere with the natural water cycle.
Water is taken from lakes and rivers, while wetlands are sometimes converted into reservoirs to produce artificial snow, which can adversely affect wildlife. Water from artificial-snow melt contains minerals and nutrients not found in natural snow, affecting vegetation. And while the melted artificial snow does return to the ecosystem, it tends to evaporate or run off quickly rather than seeping into soil to replenish groundwater. Half of humanity relies on mountains for freshwater – and supplies are expected to dwindle as Earth warms – so such effects are well worth thinking hard about.