Glaciers Don’t Lie
4 years, 3 months, 21 days, 17 hours
29 March 2025
‘Nothing that happens in mountains, stays in mountains. In one way or another we all live downstream’.
That was the powerful closing statement of the UNESCO report Mountains and Glaciers: Water towers published on 21 March as part of World Day for Glaciers, within the 2025 International Year of Glaciers’ Preservation, which might be seen as an increasingly desperate attempt to get the world to pay attention to the seriousness of something we all sort-of know about but are too busy to worry about.
Since 2000 about 5% of the world’s glacier ice has melted, according to the ‘Community estimate of global glacier mass changes from 2000 to 2023’ published in Nature in February. Page 3 has a compelling visual of the spread of that loss globally. But to put it a way that may resonate harder, the 273 billion tonnes of ice lost each year is the amount that would sustain the world for 30 years.
So you may not live anywhere near a glacier, and if you do, that might not be for much longer. But for me the critical point of the UNESCO report is that whilst only 15% of the world’s population (about 1.1 billion people) live in mountainous regions, around 60% of all the world’s freshwater comes from mountains, and in some areas it is 90%. For example Santiago, where I spent a week with colleagues at the Inter-American Development Bank annual conference, has been highly water-stressed in recent years and is critically dependent on water from the nearby glaciers, which supply 70% of summer needs. Moreover melting glaciers are not just an issue for water supply (mostly to agriculture, 72%, then industry, 15%, and domestic, 13%), but also for increased flood risk and rising sea levels. Of course the last of these affects us all. Melting snow adds about 1mm to sea level rise each year, exposing 200,000-300,000 additional people to flooding each time.
And ultimately, bad enough as this all is, it is not just about water. Climate change, land use, development, water, biodiversity, are all interconnected issues, as detailed in the 2024 IPBES Thematic Assessment Report on the Interlinkages among Biodiversity, Water, Food and Health that I will cover more in my next piece.