The report highlights previous studies that predicted glacier volumes in this region could decline between 45% and 90% through the 21st century.
Rising temperatures are a serious threat to the eight countries including China, India, Pakistan and Afghanistan in the Hindu Kush Himalayan region. Fresh water from the region's glaciers flows into 10 major river basins, contributing to the drinking water, irrigation and energy needs of approximately 1.9 billion people, or about a quarter of the world's population.
"The consequences are pretty extreme. We are concerned, and we are worried," said one of the report's authors, Philippus Wester, chief scientist with the International Centre for Integrated Mountain Development. "Urgent climate action is needed."
Glaciers have been retreating and thinning in the area since the 1970s, the report says, but there's been an accelerating rate of retreat since then. This loss has caused severe economic damage and floods, landslides and deadly epidemics. Global warming has also reduced snow cover and degraded permafrost.
The consequences of inaction will be devastating, impacting food and water supplies and raising the risk of mass population displacement, the assessment says.
Climate change will reduce how much food farmers will be able to produce in this part of the world. About 70% of the population of this region are farmers, and there is already great food insecurity there.
Warmer water temperatures will encourage the growth of invasive species. Extreme floods and droughts may "destroy the food production base of the region," the report said. Rivers that farmers and energy companies rely on, like the Ganges, Yangtze, Mekong and Indus, will also be hurt by glacier melt.