Blog Post

How Do Mountain Glaciers Act Like Water Towers for the Planet? What Makes Them So Important?

Samantha Hyde, Senior Program Manager for National Geographic Labs, discusses the critical importance of mountain glaciers — water resources that support nearly a quarter of the world’s population.

By Samantha Hyde

Mountain systems provide an important supply of water, acting as a water tower for people and ecosystems downstream. Water is stored in mountain glaciers, snowpack, lakes, and reservoirs. During warmer periods in the year, water is released, helping to sustain downstream communities.

In addition to their water supplying role, mountain environments provide a range of other services. About half of global biodiversity hotspots on the planet are located in mountain regions, containing one third of all land-based species diversity. Mountain ecosystems also provide key resources for human livelihoods, are home to important cultural and religious sites, and attract millions of tourists annually.

A recent study in Nature concluded there are 78 of these natural water towers worldwide, defined by their altitude, roughness, and water storage capacity. These 78 global water towers provide water to 1.9 billion people on four continents. For the first time, scientists assessed the mountain glacier-based systems, ultimately finding that the most important and relied-upon water towers are some of the most vulnerable, with many located in high mountain Asia.

These vulnerabilities are a result of a number of major factors, including sociopolitical changes and climate change. Water towers are highly sensitive to environmental change and are warming faster than low-lying areas. As a result, glaciers are losing critical mass and leaving the downstream communities and ecosystems at risk. That means 1.9 billion people’s water supply are at risk.

To learn more about water towers and their vulnerability, visit

Back to Top
About The National Geographic Society

The National Geographic Society is a global nonprofit organization that uses the power of science, exploration, education and storytelling to illuminate and protect the wonder of our world. Since 1888, National Geographic has pushed the boundaries of exploration, investing in bold people and transformative ideas, providing more than 15,000 grants for work across all seven continents, reaching 3 million students each year through education offerings, and engaging audiences around the globe through signature experiences, stories and content.

To learn more, visit or follow us on Instagram, LinkedIn, and Facebook.