Canada’s glacial melting ‘outside the scope of normal’

The St. Elias mountain range crossing Yukon, British Columbia, and Alaska is the highest coastal mountain range on Earth, and their ice cover is six times larger than the ice fields of the Canadian Rockies, making it the biggest icefield in the world outside Greenland and Antarctica.

In a 2018 report, State of the Mountains, experts estimate that the glaciers in the St. Elias Mountains are losing more ice than any other alpine area in the country.

“We as Canadians are stewards of about a third of the world’s mountain glaciers and ice caps, so this is our responsibility,” Glaciologist Gwenn Flowers, a professor at B.C.’s Simon Fraser University told CBC News.

An aerial shot of Kluane National Park’s glaciers, icefields, and small mountains taken on August 16, 2015.

Yanjipy

Flowers love the ice and has been coming to the ice fields of the St. Elias mountains for the past 13 summers. She has seen first-hand the dramatic changes in the glaciers in the Yukon, and she sees lots of reasons to be concerned based on the state of the ice.

The Kaskawulsh glacier
She and her team are currently mapping the Kaskawulsh glacier – 70 kilometers long and five kilometers wide. The glacier is already under attack from both a warming climate and diminishing snow cover. The glacier is currently losing a half-meter (1.6 feet) of ice each year.

“What the glaciers and ice sheets do makes a big difference to global sea levels, and makes a big difference to local environments where they form a water source,” she added.

kaskawulsh glacier junction from air on August 29, 2914.

Gstest

The Kaskawulsh glacier is located within the Kluane National Park and Reserve, a part of Canada’s national park system in the southwest corner of the territory of Yukon near the Alaskan border. Covering 22,013 square kilometers (8,499 square miles), the reserve is dominated by mountains and glaciers that cover 83 percent of the area.

The glacier terminates at the head of two river valleys, with its meltwater draining into the Slims River and the Kaskawulsh River. Up until May 2016, about 80 percent of the meltwater flowed northwards, through the Slims River and into Kluane Lake, while the other 20 percent flowed into the Kaskawulsh River and then flowed east and south into the Alsek River, draining into the Pacific Ocean.

A documented case of “river piracy”
In the spring of 2016, a period of intense melting took place, causing a gradient change that redirected the meltwaters to the Kaskawulsh River, causing the Slims River to disappear in a period of four days. This was the first documented case of “river piracy” in modern times.

The big concern is that as global warming accelerates, we could expect to see more of these river piracy events taking place. More worrying to many scientists are the effects on the environment and local communities, human and wildlife, if sudden changes in river flows occur.

“We’re seeing a 20 percent difference in area coverage of the glaciers in Kluane National Park and Reserve and the rest of the UNESCO world heritage site [over a 60-year period],” Diane Wilson, a field unit superintendent at Parks Canada, told CBC. “We’ve never seen that. It’s outside the scope of normal.”

Sections of the newly exposed bed of Kluane Lake contain small pinnacles. Wind has eroded sediments with a harder layer on top that forms a protective cap as the wind erodes softer and sandier sediment below. These pinnacles, just a few centimeters high, are small-scale versions of what are sometimes termed “hoodoos.”

Jim Best/University of Illinois

The environmental impact
The annual State of the Mountains report also mentions the Sims River, noting that “the beheading of Slims River” is likely to be “permanent,” and arguing the phenomenon could happen elsewhere as the world’s glaciers retreat.

In the report, they note: “Recent history has shown that river reorganization due to climate change can, in some cases, have large consequences for people and ecosystems … As we move toward a world with far fewer glaciers and smaller ice sheets, land that has been covered continuously by ice for many tens of thousands of years will become ice-free.”

The report goes on to say “many rivers in high mountains will be redirected via more hydrologically expedient paths to the sea. In most instances, the redirection will be inconsequential. In other cases, however, the changes might have more significance.”

In the St. Elias mountains region, temperatures have already risen 2 C in the past 50 years. And in the 30 years covering 1977 to 2007, the Kaskawulsh lost 17 square kilometers of ice. What is happening in the Yukon necessitates a call to action and encourages us to think seriously about how our behavior today influences the landscape of the future.