[ad_1]
CLIMATE | Early warning system
CBC News
Sunday, October 28, 2018, 4:17 pm – Gwenn Flowers, a glaciologist, goes back and forth across a vast glacier in southwestern Yukon pulling a radar device mounted on her skis behind her.
"As Canadians, we manage about a third of the world's glaciers and ice caps, so that's our responsibility," said Flowers.
Researchers say the dramatic changes to glaciers in the Yukon signal early on what climate change could bring to the rest of the world. And the flowers see a lot of reasons for concern reflected in the state of the ice.
(See also: The melting of glaciers triggers the largest tsunamis in the world)
Glaciologist Gwenn Flowers is towing equipment over the Kaskawulsh Glacier in the Yukon for depth. (Susan Ormiston / CBC)
Professor Simon Fraser University of BC loves ice cream. For 13 years she has been studying on the ground in the mountains of St. Elias.
His small team of three maps the Kaskawulsh Glacier – 70 km long and five km wide – while it struggles under the double threat of global warming and a decrease in coverage snow.
The research leads to an inescapable conclusion: the glacier can not compensate for the lost volume each year.
The radar box Flowers towed on skis is specially adapted to ice and sends signals to the bottom of the core of the glacier, bouncing off the bedrock. In some places, the team found ice more than 800 meters deep.
The team's research shows that the ice is dissipating quickly, but loses about half a meter a year, Flowers said. And the huge glacier recedes.
The St. Elias mountain range that runs through the Yukon, BC Alaska is less known than the Canadian Rockies and its ice fields. But its ice cover is six times larger, making it the largest ice field in the world outside of Greenland and Antarctica.
Flowers and his team are trying to better understand the evolution of the glacier and what it means for the wider environment.
"As Canadians, because we are responsible for managing this ice, I think we could do better, I think science in the Arctic should be a priority. Terrestrial and marine ice should be a national priority, "said Flowers.
(See also: NASA discovers three things that affect the spin of the Earth)
ENVIRONMENTAL IMPACT
A 2018 report, "State of the Mountains," suggests that glaciers in the St. Elias Mountains lose more ice than any other Alpine region in Canada. In the 30 years between 1977 and 2007, the Kaskawulsh lost 17 square kilometers of ice.
Temperatures have already increased by 2 ° C over the past 50 years. It is expected that they will increase by at least three more degrees by the end of the century, unless things change.
According to Gwenn Flowers, the ice on the Kaskawulsh Glacier dissipates rapidly and loses about half a meter a year. (Susan Ormiston / CBC)
The Yukon had a particularly hot month of July last summer, the hottest of the past five years, with several heat warnings issued.
Leading scientists on climate change have recently warned that the world only had a dozen years to slow global warming or risk worsening drought, floods and climate change. extreme heat. The authors of the UN's Intergovernmental Panel on Climate Change said urgent and unprecedented changes are needed to keep global warming below 1.5 ° C.
"What glaciers and ice caps are doing is having a big impact on global sea level and local environments, where they are a source of water," Flowers said.
WATER DISAPPEARANCE
Around Kluane Lake, two research stations monitor changes in Yukon's climate and glaciers.
Andy Williams arrived in the region more than 40 years ago to manage the Kluane Lake Research Station. He also founded a small air service carrying scientists, hikers and tourists to the ice fields.
He observed tremendous changes in the ice during this period. As glaciers move forward and back naturally, he says, it's not at that speed.
And the changes in this region reflect what is also happening in the Andes, or the Himalayas, "where millions of people depend on a steady stream of glaciers to provide irrigation and water. Drinking water ". If these shrink too quickly, "the results are catastrophic," he says.
The faster thinning of the Great Ice in the Yukon is already having dramatic consequences further into the mountains, such as in the jewel of Kluane Lake, the largest in the Yukon, bordering Kluane National Park and UNESCO World Heritage Site.
For 300 years, glacial runoff was the main source of water for Kluane Lake on the Slims River. But in May 2016, Kluane Lake levels dropped steeply. The problem was a case of "river piracy" – incredibly rare and extremely important. The terminus or end of the Kaskawulsh Glacier had retreated sufficiently to allow a glacial lake that fed the Slims River to drain suddenly as the glacier flow regained a new direction towards a new river.
He left the Slims River with little water as he descended the mountain to Kluane Lake.
Bob Dickson, the chief of the Kluane First Nation, sits on the dry bed of what was once a glacier fed river. (Susan Ormiston / CBC)
That summer, Kluane Lake lost 1.7 meters and remains low.
In the Burwash and Destruction Bay communities of the Kluane First Nation, the shoreline has retreated, restricting access by boats to traditional fishing grounds. Previous spawning areas of whitefish and trout have emerged above the waterline.
"We can not change that," says chef Bob Dickson.
"We have to live with this lake in a different way, the hunting areas, the fishing areas, are changing, so we have to learn again."
The Alaska Highway, one of the northern highways connecting the Yukon to Alaska, divides the Slims River Valley in two. Now, huge dust storms often obscure the road, forcing motorhomes to slow down. The river bed, normally covered with water at the end of August, seems dry.
A camper walks through a dust storm on the Alaska Highway where he divides the Slims River Valley. The dust comes from a dry riverbed that was fed by the Kaskawulsh Glacier.
"There can be dust storms all over the valley, and all the glacier flour is blown," says Chief Dickson. "They are really terrible, you can not even see."
Parks Canada is monitoring "unprecedented" changes.
"We are seeing a 20% difference in glacier coverage in Kluane National Park and Reserve and in the rest of the UNESCO World Heritage Site. [over a 60-year period]Said Diane Wilson, Superintendent of a Field Unit at Parks Canada.
"We've never seen that, it's outside the normal range.
"Kluane is an icon, people are excited to visit this wonderful place, but they should know that it is changing Climate change knows no boundaries."
With files from Mia Sheldon. Vignette: The Kaskawulsh Glacier in the mountainous St. Elias region of the Yukon is often referred to as the "Ice Road". (Susan Ormiston / CBC)
This article was published on CBC.ca by Susan Ormiston.
LOOK BELOW: AN EXCEPTIONAL PERFECTLY RECTANGULAR ICEBERG EXPLAINED
You can also As
Source link
