By Andru McCracken
If you hoped that the cold wet weather we experienced this summer may have built up local glaciers like Castle Creek or Zillmer, or even slowed their fate, think again. In fact, regardless of how well the inhabitants of earth deal with climate change, in 100 years the majestic glaciers of our valley will be, for all intents and purposes, gone – less than 10% of their current size, making a vastly smaller contribution to local ecosystems.
That was the message from UNBC Professor Brian Menounos in a natural history talk to a packed house at the McBride and District Museum.
His talk, part of the McBride and District Library’s Natural History series was billed online as ‘Castle Creek Glacier,’ Menounos’ title was ‘The science behind glaciers and glacier change,’ but a better title would have been ‘Climate Change: Why Local Glaciers are Doomed.’
Ph. D student Ben Pelto spent nine field seasons (spring and fall) on a number glaciers in our region. Every year the glaciers are losing mass. Pelto spent part of his time on Zillmer Glacier; it’s on Mount Zillmer and it’s very close to Valemount.
He was researching with the help of a grant from the Columbia Basin Trust and BC Hydro. They funded the research to help get an understanding of the contribution that glaciers are making to stream flows and hydroelectric generation, and they wanted insights into what could be expected in the future.
What’s happening is pretty clear: over the course of Pelto’s field work from 2013 to 2019, Zillmer Glacier lost 5.73 meters of ice.
“Essentially this is the equivalent of taking a slice of 96 cms off the entire glacier per year in thickness,” said Pelto
To put that in perspective, the average height of the glacier is 70 meters.
During a 50-minute talk to a standing-room-only crowd, Menounos laid out the foundation of their work in the mountains, the definition of a glacier, the methods they use to estimate the growth or decline of glaciers.
It included a fascinating introduction to Light Detection and Ranging (LiDAR), which detects changes in the height of the glacier using lasers from an airplane. Ultimately the height change map of Zillmer published with this article is a product of LiDAR. Blue shows where the glacier is growing, red shows where the glacier is shrinking.
LiDAR captures incredibly detailed information on the exact reduction in size of the glacier each year. Combined with on-glacier snow pit digging and drilling to determine the depth of the glacier in different locations as well as the measurement of run off, researchers are confident in their numbers.
In a graphic showing several scenarios of climate change, best to worst, no instance showed the retention of glaciers. Menounos said that as glaciers shrink and recede lower, their doom will be accelerated.
Menounos left the crowd with this: regardless of what action is taken in the face of climate change, local glaciers are fading fast and in 100 years will be nearly gone.
