Science, 2 June 2022

Over the past four decades, three-quarters of the European Alps above the tree line have experienced an increase in plant growth, a process known as “greening.” Although greening could increase carbon sequestration in the region, accelerated snow melt in combination with more habitable conditions for plant growth will lead to harmful environmental consequences in the future. The retreat of snow cover exposes large areas of dark ground to the sun, which absorbs more sunlight and warms faster. This creates a feedback loop that accelerates ice and snow melt. Meltwater from glaciers and snow provides nearly half of the world’s fresh water resources. The loss of these frozen water stores in the Alps jeopardizes seasonal water availability for downstream communities throughout Central Europe. Increasing plant growth in the Alps could therefore have widespread and long-term regional consequences that exacerbate ice loss and disrupt ecological structures, threatening vulnerable alpine and downstream economies and communities.