The glaciers of western Canada, one of the world's most picturesque mountain regions, are likely to largely melt away over just three generations, scientists say.

By 2100, the glaciers of Alberta and British Columbia are set to shrink by 75 per cent in area compared to 2005 levels, and by 70 per cent in volume, according to their predictions.

But in two out of the three regions that were studied, the decline could be even more dramatic - over 90 per cent.

The loss will hit many sectors, from agriculture, forestry and tourism to ecosystems and water quality, the investigators warned.

The study, published in the journal Nature Geoscience, was headed by Garry Clarke, a professor at the University of British Columbia in Vancouver.

"The disappearance of (the) glaciers ... will be a sad loss for those who are touched by the beauty of Canada's mountain landscapes," Clarke told AFP.

"When the glaciers have gone, we lose the important services they provide: a buffer against hot, dry spells in late summer that keeps headwater streams flowing and cool, and sustains cool-water aquatic species."

The team used a computer model that combined four well-known scenarios for global warming this century, with data about three glacier-covered regions and dynamics of ice melt.

Even at the lowest projected warming, most of the glaciers are essentially doomed, according to their forecast.

"Few glaciers will remain in the Interior and Rockies regions, but maritime glaciers, in particular those in northwestern British Columbia, will survive in a diminished state," the investigators said.

The regions studied by Clarke's team cover 26,700 square kilometres - an area almost the size of Belgium and bigger than the glacial Himalayas, and with an ice volume of 2980 cubic kilometres.