Local glaciers fading fast

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.

A height map of Zillmer Glacier shows the reduction in size of the glacier between 2013 and 2019. The glacier is declining in volume and area. Small blue areas (accompanied by bright red marks of equal size) show the movement of crevasses. Things are changing quickly. Dark red areas show a 5m decline in the glacier surface.

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.

Regardless of action taken on climate change, local glaciers will continue to disappear. Dr. Menounos showed this graph from Projected deglaciation of western Canada in the twenty-first century, a paper published in nature Geoscience. First author Garry K. C. Clarke

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.

 

Did you know the Goat could not operate without people buying the newspaper? Subscribe today!