Glaciers are melting rapidly around the world, including in Canada, and human-caused climate change is now considered to be the main driver.
Thousands of glaciers in B.C. and Alberta are expected to lose 60 to 80 per cent of their combined volume compared to 2005, depending on how much CO2 gets added to the atmosphere between now and the end of the century.
Many of the glaciers in the Rockies will disappear altogether, predicts the new study published Monday in Nature Geoscience. In the Interior and Rockies regions, "ice area and volume losses will exceed 90 per cent," except in the most optimistic climate change scenario considered, it says. Glaciers in coastal northwestern British Columbia are expected to "survive in a diminished state."
But the most valuable information coming out of the new study is the details, says lead author Garry Clarke, professor emeritus of glaciology at the University of British Columbia.
Previous studies mainly focused on the amount of snow that would replenish the glaciers each year and the net melting over time as the climate warms.
Clarke's study goes into how glaciers will flow and break up, and where their water will go under four climate scenarios considered by the Intergovernmental Panel on Climate Change in its Fifth Assessment Report in 2014.
"It's essentially a resource that people can use if someone wants a glacier ski resort somewhere in the Rockies and they wonder what it might be like 50 years from now," said Clarke.
The details of how the glaciers will melt may also have an impact on hydroelectric production on glacier-fed rivers, as well as agriculture that relies on the water for irrigation, alpine tourism, and resource development, including forestry, the paper says.
Already, Clarke says, he has been working with B.C. Hydro to plan changes to hydroelectric power production in the future. Luckily, in B.C., climate change is expected to increase rainfall, which is expected to largely make up for the loss of the glacier meltwater.
"The main change for them is the timing of water delivery to the reservoirs."
Other parts of the world may not be so lucky, and similar models may be crucial to help them plan for drier times.
There will be other impacts in Canada as well, including the near-disappearance of the Columbia Icefield, a major tourist attraction in Jasper National Park. It's visited by millions of people each year aboard convoys of special snow coaches. It's also an important source of snow and ice melt for the Athabasca, Saskatchewan and Columbia river basins.
The Columbia Icefield's biggest glacier, the Athabasca, is currently losing more than five metres of ice a year.
The new model shows that by 2100, under a best-case scenario where the amount of carbon dioxide in the atmosphere peaks at just 490 parts per million (it's currently close to 400 ppm), the icefield will be reduced to multiple small patches. But if CO2 emissions grow to 1,370 ppm, it will have shrunk to almost nothing by 2100.
Clarke hopes the value in the study isn't just directly practical, but will also help people better understand the consequences of climate change and motivate them to take action against a problem he describes as urgent and "dead serious."
"If you look and say, 'Here's a glacier that you ski on right now and here's what it will look like 20, 30, 50 years in the future' and they can see the consequences, I think it's a stronger message. It works a little bit more viscerally for people that are not scientists."
More complicated than imagined
The study took 10 years of work. In collaboration with researchers at the University of Iceland, the University of Victoria, the University of Northern British Columbia, he incorporated the "flow physics" of ice and snow into a computer model of western Canada and its glaciers.
"It was much more complicated than we even imagined," Clarke recalled.
When the starting point for the model was 2,000 years ago, it accurately predicted what the glaciers look like today.
"Then we subject them to the climate of the future and we see what happens to them," Clarke said.
He thinks now that the technique has been worked out, it would be useful to apply it to other parts of the world — something he's interested in helping out with.
But he doesn't personally want to lead another study like this.
"It's a bit depressing to actually be calculating losses the whole time," he said. "I didn't get into science to be that kind of person."
Even if he wanted to, the funding might be hard to come by — as it is, he thinks even the current study "would be pretty hard to put together now." That's because it started a decade ago and was funded by the Canadian Foundation for Climate and Atmospheric Sciences, which was launched under Liberal prime minister Jean Chrétien and not renewed by Stephen Harper's Conservative government when its funds ran out in 2011.Suggest a correction