Home Glaciers ‘Bad year for glaciers’: climate change threatens glacier behind Edmonton water source

‘Bad year for glaciers’: climate change threatens glacier behind Edmonton water source

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The province has long passed the oppressive “heat dome” that suffocated cities last summer, but warmer temperatures this year have had a lasting effect on the glacier that supplies Edmonton’s water supply.

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The terminus of the Saskatchewan Glacier has experienced a 10-meter thinning this year, said Brian Menounos, professor of earth sciences at the University of Northern British Columbia and holder of the Canada Research Chair in Land Changing. glaciers. It is also the glacier that feeds the North Saskatchewan River, Edmonton’s only source of drinking water.

“We have known for a number of years that – largely because of greenhouse gas emissions – we have accelerated the melting of the cryosphere,” he said, referring to the part of the planet covered with ice or snow. “This is a symptom of a bigger problem as it has been an exceptionally bad year for glaciers overall.”

In a social media posting, Menounos shared an image of the Columbia Icefield that shows a change in elevation over the past year, measured by laser altimetry. The technology uses an airplane to bounce laser light off the surface of the icefield about once a year. The time it takes for light to reflect off the plane and trigger a sensor allows scientists to measure the change in surface elevation.

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Sparse blue dots in the image show areas of increased elevation – where the ice field has gained mass – while the overwhelming red area indicates a decrease in elevation due to melting. The greatest decreases can be seen at the ends of the Athabasca and Saskatchewan glaciers, both of which look like dark red tongues extending north and east.

“We’re finding pretty much widespread thinning in all elevation bands on the icefield, and that’s something we haven’t seen to date,” he added, noting that although As scientists have been monitoring glaciers for years, they only started using lasers. altimetry in the ice field since 2017.

Glaciers are an important source of fresh water, particularly in Western Canada. An article co-authored by Menounos revealed that the the world’s glaciers now lose 267 billion tonnes of ice each year (one billion tonnes of ice is equivalent in mass to 10,000 fully loaded aircraft carriers). He also cited research suggesting that more than a billion people around the world could face water shortages by 2050.

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“Anytime you talk about a freshwater resource that Canadians depend on – snow and ice collectively – that’s a cause for concern,” Menounos said.

Matthew Chernos, a Calgary-based hydrologist and consultant, said the high alpine glaciers feeding Alberta’s river systems act as natural reservoirs. While the North Saskatchewan River is mostly made up of rainwater and snowmelt by the time it reaches Edmonton, he said, glacier melt is a big part of the river’s flow in July and August. , when the glacier’s winter snowpack melted.

And as Alberta warms, Chernos added, more of that snowpack will melt sooner, increasing the length of the low flow season and the amount of melting glacier ice, a resource not renewable.

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“The only way to compensate for that would be more precipitation, and it’s also not something that should happen in the future,” he said. “In fact, most of Alberta should be even drier in the summer. “

Scientists quickly noticed that the discoloration of glaciers was also threatening sensitive aquatic ecosystems that depend on cooler water to stay healthy, and the irrigation demands of the agricultural industry.

Menounos is also not optimistic about improving weather conditions to correct the problem.

“In the last 30 to 50 years of monitoring these glaciers, the odd positive year, where the snow was abundant, does not compensate for the continuous melt that we get each year,” he said.

“It’s kind of a losing battle.”

– With files from The Canadian Press

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