The UN World Water Development Report 2025, titled Mountains and Glaciers: Water Towers, highlights the indispensable role that mountain regions and alpine glaciers play as natural “water towers,” fuelling freshwater flows that support billions of people, agriculture, energy, and ecosystems. It was released on 21 March 2025, coinciding with World Water Day and the inaugural World Day for Glaciers, underscoring its critical timing. The report reveals that mountain “water towers” contribute 55–60% of annual global freshwater flows, sustaining about 2 billion people, with 26–41% of the global glacier mass at risk by 2100 under warming scenarios of 1.5–4 °C.
Climate-driven glacier retreat is increasing the volatility of water supplies initially causing higher flows known as “peak water,” then followed by sharp declines once glaciers pass this threshold, as already observed in the Tropical Andes, Western Canada, and Swiss Alps. The consequences are profound: up to 2 billion people may face risks to drinking water and agriculture, while two-thirds of global irrigated agriculture could experience stress. The report warns of amplified hazards, flooding, drought, landslides, glacial lake outburst floods, and permafrost thaw, challenging both mountain communities and downstream populations. In response, it calls for urgent, integrated action: sharply reducing carbon emissions, boosting cryosphere monitoring, strengthening transboundary collaboration, and implementing adaptive water governance across basin scales. Practical recommendations include bolstering infrastructure and finance, engaging mountain communities, improving data systems, and designing policies tailored to mountain ecosystems, aligned with Sustainable Development Goal 6 around clean water and sanitation