The study, authored by 32 scientists from around the world, assessed the vulnerability of the planet's 78 mountain glacier-based systems.
These natural resources, known as mountain water towers, store and transport water via glaciers, snowpacks, lakes and streams.
Up to 1.9 billion people globally - roughly a quarter of the world's population - get their supplies from these systems.
New research shows them to be at risk, in many cases critically, due to the threats of climate change, growing populations, mismanagement of resources and other geopolitical factors.
Tobias Bolch, of the School of Geography and Sustainable Development at the University of St Andrews, contributed to the study as an expert in the changing mountain cryosphere and its impact on the downstream society.
He said: "The study quantified for the first time both the natural water supply from the mountains as well as the water demand by society, and also provided projections for the future based on climatic and socioeconomic scenarios.
"The projected loss of ice and snow and increasing water needs makes specific densely-populated basins located in arid regions, like the Indus basin in South Asia or the Amu Darya basin in Central Asia, highly vulnerable in the future."
The authors concluded it is essential to develop international, mountain-specific conservation and climate change adaptation policies and strategies..
The most relied-upon mountain system in the world is the Indus water tower in Asia, according to the research.
It is made up of vast areas of the Himalayan mountain range and covers portions of Afghanistan, China, India and Pakistan, and is also one of the most vulnerable.
High-ranking water tower systems on other continents are the southern Andes, the Rocky Mountains and the European Alps.