As the helicopter turned toward Peyto Glacier, located in the Park Ranges of the Canadian Rockies, John Pomeroy and his team of scientists gasped.
Prof. Pomeroy, a distinguished professor and director of the Global Water Futures Observatories at the University of Saskatchewan, has studied the ice mass in Banff National Park since 2008, visiting several times a year to adjust weather stations and photograph changes.
He is familiar with the glacier’s rapid melting. It retreats tens of metres per year – 80 metres in 2021 alone. But on the helicopter ride last September, he was stunned to see how much it had transformed since even his previous visit.
“You think you know a place, and then you see it two months later and it’s changed dramatically,” Prof. Pomeroy said in an interview. “It’s a very heartbreaking moment.”
The glacier looked to him like an inflatable toy losing its air, getting thinner while retreating horizontally. At the glacier’s base, the icefield that once filled the valley had been replaced by a lake. The ice was also darker than one might have expected, owing to soot and ash from wildfires that have dramatically intensified in recent years – hastening the glacier’s demise.
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As the country contends with longer and more destructive wildfire seasons, Canadians are growing accustomed to seeing summer skies turned grey and orange by smoke. This pollution has been linked to increased risks for heart health, cognitive function and dementia. But the damage extends beyond physiological well-being: ash drifting onto mountain glaciers is accelerating ice melt.
Clean glacier ice reflects about 30 per cent of solar radiation, but ice that has been darkened with soot and ash reflects around half of that, said Prof. Pomeroy. A research paper he co-authored in 2022 found that long after fires have been extinguished, the darkened surface of the glacier continues to accelerate ice melt by about 10 per cent.
The broader implications are troubling. Glaciers supply drinking water, provide the headwaters for major rivers and keep streams flowing during periods of drought.
“And, the conditions that cause the melt of the glaciers also make this planet very challenging to live on,” Prof. Pomeroy said.
“It will mean air temperatures that occasionally exceed those which humans can survive in. It will mean immense droughts, punctuated by severe floods, and reliance on rain water,” he added. “As the glacier ice makes its way into the oceans and causes sea level rise, that will inundate many of the coastal areas around the world.”
Prof. Pomeroy’s team also stumbled upon a somewhat unexpected finding. When they began recording glacial surfaces “dark as a prairie field” in 2016, Prof. Pomeroy knew that at least some of it was because of wildfires and figured it would eventually wash away with rain. But the darkness persisted, year after year.
In July, 2018, the team collected ice samples from Athabasca Glacier, located in Jasper National Park, and brought them to colleagues at the University of Saskatchewan’s Toxicology Centre. There, scientists used a scanning electron microscope, among other instruments, to examine the environmental DNA.
“What they found was amazing,” Prof. Pomeroy said. The tests showed the expected soot and organic material, but also revealed a whole mix of life and microbes within the ice – algae, bacteria, fungi and viruses. “Some of the algae were filamentous, and were actually holding the soot on to the ice crystals,” he said.
Cryoconite, a powdery windblown dust made of a combination of small rock particles, soot and microbes, can be found all over Peyto Glacier.
The algae blooms cling on to the ash, a nutrient source, and absorb more solar radiation, said Prof. Pomeroy, adding that colleagues have reported this elsewhere as well, including in Greenland, South America and in the Himalayas.
Wildfire smoke in the sky, on the other hand, has the opposite effect, decreasing the amount of solar radiation reaching the glacier surface and preserving the ice.
But what can be done about glacier melt? Some ski resorts have invested in thermal blankets, also called geotextiles – large synthetic blankets that cover and insulate the ice surface and reduce melt.
British Columbia’s Sun Peaks Resort became the first in Canada to employ the technology, announcing in May that it purchased specialized mats by the Finnish company Snow Secure, designed to retain 75 to 80 per cent of snow. The resort said it harvested and shaped 14,000 cubic metres of snow into a pile, which measured 300 feet long by 100 feet wide by 30 feet tall, and covered it with the mats, which will be removed ahead of this year’s ski season. Similar technology has been used on glaciers in Switzerland, Austria and China.
One 2021 study of geotextile use on glaciers in Switzerland found it reduced melt by 59 per cent, and could be efficient and profitable for ski resorts and other tourist attractions. However, the researchers said upscaling was “neither feasible nor affordable,” and that the public should not have false hopes about the use of these mats as a solution to climate-driven glacier melt.
“Seeking technocratic solutions for saving glaciers at the large scale cannot be a priority in comparison to efforts to mitigate CO2-emissions,” the researchers wrote. “Abating greenhouse gas emissions is the only way of efficiently limiting future atmospheric warming and, hence, reducing the rates of glacier mass loss globally.”
It’s a conclusion Prof. Pomeroy agrees with. Admittedly he is “very, very worried” about not only glacier melt, but also increasingly intense wildfires, prolonged droughts and all that may lie ahead. “When I pull it all together, I’ve always got to take a bit of a deep breath, because it’s scary business,” Prof. Pomeroy said.
“But there’s still time for us to avert this, and I think that message of hope needs to come out as well: If we can start to reduce greenhouse gas emissions very rapidly now, we can still save many of the glaciers in Canada and we can save ourselves from the worst effects of this.”