University of Saskatchewan hydrology researchers have discovered that exposure to wildfire smoke can cause glaciers to melt faster which affects mountain runoff. The mountain runoff in turn provides major freshwater resources downstream.
A PhD candidate who was part of the research team says the occurrence and severity of wildfires is increasing. Caroline Aubry-Wake says, “It is linked with climate change and past forest management, and has wide-ranging consequences for human activities and ecology.”
A team of USask hydrology researchers observed that in years with increased fire activity, wildfire smoke left ash and soot deposits on the glacier ice, causing it to darken and to melt much faster. The report said the surface of the glacier stayed dark even once the fire season had passed.
The weather also played a part in the effects on glacier melt. Smoky days are warmer and drier than sunny days and contain less solar energy. On sunny days, the darker ice saw a higher melting rate. On the flip side of the coin, if smoke was present in the air, the ice was preserved due to the decreased amount of sun reaching the glacier surface.
Aubry-Wake says the scale is tipping towards the impact of the ice being darkened by soot, “”Five years of data is that soot that deposits on the ice making the ice darker can last multiple years so even when there is no more smoke, when there’s no more fire activity, we still see some legacy impact of those forest fires and increased melt even after the fires and that’s going to have a large impact. It can increase the melt up to 10 per cent.”
Aubry-Wake says the fire can be happening quite far away but the smoke can make its way over the glacier. She says other studies have shown for instance the wildfire at Fort McMurray reached Greenland and affected the melt there while wildfire smoke from Australia reached the Andes. She says with this new information they can include their understanding of how wildfires affect the melting of glacier ice in their predictions for runoff and expected volume of water in downstream rivers.
Dr. John Pomeroy, Canada Research Chair in Water Resources and Climate Change and director of the Centre for Hydrology was a co-author of the study and he says, “It’s incredible how we can connect the dots about climate change like this. We see droughts causing fires, fires forming huge plumes of smoke and ash, the ash covering the glaciers, and the glaciers melting at increasing rates because of the fires.”
Pomeroy describes the glaciers as the earth’s savings account for water in the future and are a crucial part of a UNESCO world heritage site in the Rockies. He says better understanding of the impact of wildfires will improve their hydrological modelling of mountain resources.
From 2015-2020, a team of USask hydrology researchers observed each melting season at the Athabasca Glacier, part of the Columbia Icefield in Jasper National Park, Alberta. Based on fire activity that year, they analyzed the accumulation of soot and ash on the glacier and the effects of solar activity that causes glaciers to melt. Study findings were recently published in the American Geophysical Union’s journal, Earth’s Future.
The research team included Caroline Aubry-Wake alongside supervisor Dr. John Pomeroy (PhD) and fellow PhD candidate Andre Bertoncini. The wildfire season in Canada typically lasts from May to September.
