The real picture, as shown by data, reinforces the need to closely study Canada's melting glaciers for streamflow projections.
New research shows that glaciers in BC's Columbia River Basin are substantially thicker than previously thought, but researchers say this won’t offer much of a lifeline against melt due to climate change.
The research, led by University of Northern British Columbia scientists and supported by PICS, was published in September 2020 in the Journal of Glaciology.
The researchers used ice-penetrating radar to measure ice thickness on five glaciers in BC’s Columbia Mountains from 2015 to 2018, and then combined that data with two previous surveys for two glaciers in the Rocky Mountains.
After collecting more than 34,000 data-points measured over 182 kilometres, they found that glacier thickness is, on average, 38 percent thicker than previous computer model estimates. Furthermore, they calculated that the ice volume for the Upper Columbia Basin is 122.5 ± 22.4 km3, which is 23% greater than the range of previous estimates.
Five of the seven study glaciers lie within the Columbia Mountains (the Conrad, Kokanee, Zillmer, Illecillewaet, and Nordic glaciers), while the West Washmawapta and Haig glaciers lie within the Rocky Mountains.
Ben Pelto, who successfully defended his UNBC Natural Resources and Environmental Studies PhD dissertation in October, is the lead author in the study. He says the huge amount of local data gathered enabled much more Columbia basin-specific analysis than predecessor regional and global estimates were able to do. He says while some glacial ice at high elevations may exist years or even a couple of decades longer than previously anticipated, this apparent boost in glacier size will unfortunately do little to change the current decline in glacier runoff and shrinkage.
“At current rates of glacier mass loss for this region, our study shows that glaciers will disappear from the basin in about 65–80 years. This aligns with evidence from separate studies which found that glaciers in the basin will lose 60 to 100% of their ice by 2100, depending on green-house gas emissions,” he says. “Disappearance of these glaciers will negatively affect the basin’s surface hydrology, freshwater availability and aquatic ecosystems, potentially affecting fish stocks and habitat.”
Pelto says in fact peak water flow from these shrinking glaciers may have already occurred, as shown separate studies, because as glaciers retreat they lose their low-elevation ice which melts first.
“Essentially, glaciers act as on-demand water towers, supplementing streams with cool, plentiful water during late summer when runoff from snowmelt has passed. For example, the Mica Basin in the Northeast Columbia Basin contributes up to a third of streamflow from glacier ice melt during August and September,” he says. “Ice area loss is reducing the capacity for glaciers to act in this manner.”
The Columbia River basin produces over 40% of hydroelectricity in the United States, with the Canadian portion of the upper basin providing 30–40% of its total runoff, predominately from snowmelt but also ice. The Columbia Region also provides almost half of BC Hydro's total generating capacity.
Pelto says Canada's glaciers have not been closely studied like their European counterparts, and this study suggests the value in doing so.
"Ice thickness measurements should be made for other glaciers in the Province, such as BC’s Coast Mountains, in order to improve models of glacier retreat and disappearance and their streamflow projections for regional and global purposes, including hydropower planning and downstream fish and aquatic ecosystem studies."
The full report, Bias-corrected estimates of glacier thickness in the Columbia River Basin, Canada is available at this link.
Ben Pelto completed this research in 2020 as part of his successfully defended PhD under the supervision of Professor Brian Menounos at UNBC. In late 2020 Ben started a two year Mitacs Elevate postdoc at UBC/BC Hydro studying "Cumulative effects of climate and land cover change on river flows in mountain catchments."