The last glacier in Metro Vancouver is disappearing one drip at a time.
Located in the Coquitlam watershed, the Coquitlam Glacier was once expected to maintain its chilly disposition until approximately the year 2100.
However, following a more recent inspection, Metro Vancouver geoscientist Dave Dunkley said he now believes the glacier might warm into water and slush 50 years earlier than expected.
“Based on what I’ve seen, 2050 is not a wild guess,” he said.
The glacier has shrunk, flattened and cracked. Its grip on the surrounding bedrock has weakened, giving it the appearance of climbing down. Dunkley spotted one gap about a half-metre across and 20 metres down. There was water flowing at the bottom of it.
The glacier is one of our “canaries in the coal mine” when it comes to climate change, Dunkley explains.
Discussing the glacier following a 2018 study, geoscientist John Clague predicted the berg would be gone by the end of the century, “maybe even earlier.”
“Glaciers are thermometers. They tell us exactly what climate is up to,” Clague explained.
The age of ice
Far older than the city it’s named for, the Coquitlam Glacier dates back at least to the Little Ice Age when glaciers dotted the province. However, there’s a chance it’s much older.
On a recent expedition to the glacier, Dunkley and Clague came across an old piece of wood. That wood might have once belonged to a tree which had the misfortune of being in the path, and then being absorbed by, the advancing Coquitlam Glacier.
Carbon dating marks the wood as being about 2,500 years old.
“We think the ice probably was still there 2,500 years ago,” Dunkley said of the glacier. “it’s just somehow hung in there.”
The glacier was able to withstand the 20th century largely due to its location.
“It’s nestled into a little pocket in the mountains that face north so the sun is blocked out from the east, west and south sides. . . . I think that’s really the only reason it’s survived.”
Long, hot century
By the time Coquitlam was incorporated the glacier was already shrinking, its ice-line receding at a rate of about four or five metres each year.
Once stretching 720 metres up the valley, the glacier has now moved in from the sides of bedrock into a bowl-like formation.
The glacier once held about eight billion litres of water, according to Dunkley.
In some periods, the glacier has provided about two percent of water in the reservoir.
“It doesn’t mean a lot to water supply but it means a lot for ecosystems and water in general,” he said.
With satellite imagery, geoscientists may soon get a more precise view of the glacier, Dunkley said.
“We’ll be able to do an annual update,” he said. “We’re on the downward trend these days.”