The report, Himalayan Glaciers: Climate Change, Water Resources, and Water Security, found while glaciers appear to be retreating in eastern and central regions of the Himalayas, others in the western Himalayas are more stable and could be growing.
Dr David Molden, director of the International Centre for Integrated Mountain Development (ICIMOD), told Radio Australia he wasn't surprised by the report's findings.
"Demand is going up and the supply is potentially changing ... from the glaciers, the snow, the permafrost melt, but also from changes in precipitation patterns."
Dr Molden, who is based in Nepal and has more than 30 years' experience in natural resource management, said there had been an increase in short, intense duration storms.
"More of those, more drought and the [water] volume is changing," he said.
"It's a big issue, water security. For several reasons, one is demand for water, especially from agriculture, is going up, up, up in that region."
The Hindu Kush-Himalayan region covers eight countries across Asia and supplies river systems - including the Ganges, Mekong, Yangtze, and Yellow rivers - which serve as sources of drinking water and irrigation supplies for roughly 1.5 billion people.
Dr Molden said there was also concern that monsoon rain patterns were changing, although pointed out there was not yet enough scientific evidence to support the theory.
"When you talk to different mountain people, they'll suggest a shift is happening. It feels that way but when you look at the data there's so much variability, it's hard to detect that real shit in monsoon."
"But it's definitely something we need to keep our minds on in the future."