Asia’s mountain glaciers, which are home to the largest store of frozen water after the poles and feed many great rivers including the Ganga, will lose at least a third of their mass by the end of the century because of global warming, a new study has warned.

This prediction is based on the best-case scenario – that the world will manage to limit average global warming to 1.5 degrees Celsius over pre-industrial levels.

Scientists at the Utrecht University in the Netherlands, where the study was done, said that more than one billion people across Asia who depend on rivers Yangtze, Ganga and Mekong, which are fed by the Himalayan glaciers, for fresh water, farming and hydro-electricity will be affected.

“At the moment, it does not look like we’ll be able to keep global warming down to 1.5 degrees Celsius,” said Utrecht University’s Philip Kraaijenbrink, a physical geographer and the report’s lead author. “Unfortunately, it seems more likely that between 49% and 65% of all ice in Asia will have melted by 2100, placing a significant strain on the region.”

Under the Paris climate accord, countries pledged to keep the rise in average global temperatures below 2 degrees Celsius above pre-industrial levels to stave off the worst effects of climate change. But scientists say this is unlikely, according to a report in the science journal Nature Climate Change.