by Vivian Belik
It’s a scene that’s all too familiar to most Yukoners: it’s the middle of a cold, dark winter and suddenly you’re plunged into a blackout.
A few hours without heat or light is enough to remind most people how reliant we are on the lakes and streams that feed the Yukon River to provide a steady flow of hydroelectricity. The roiling waters of this river can generate up to 40 megawatts of energy as it moves through the Whitehorse dam. That’s enough energy to power one million 40-watt light bulbs.
So what happens if this stream of water becomes affected by climate change? That’s what the Yukon Research Centre and Yukon Energy have set out to find.
They’ve installed two monitoring stations in the Fantail River basin – the headwaters of the Yukon River – close to Atlin, BC. The stations will record information about meteorological conditions such as air temperature, precipitation and solar radiation, along with the amount of snow accumulated in the region.
There’s very little data that currently exists about this area, says Jeffrey Kavanaugh, a University of Alberta earth and atmosphere scientist who is working on the project. “One concern with changing climate is the amount of snowfall, and the timing and melt of the snowfall will change, so that means the throughput of water into the Yukon River might change as well,” he says.
Over the last few decades, the Atlin area has been experiencing warming of 0.2 to 0.3 degrees Celsius per decade. That warming means more rain and less snow, and the timing of the snowmelt is changing as well. But because there is very little data to compare what is happening today to what happened in the past, it’s difficult to estimate how this warming trend will affect Yukon River water flow in the future.
“There’s a gap in the records,” says Kavanaugh. “It’s a pretty big unknown, which is concerning if you’re basing a lot of power generation on water that comes from this region.” Particularly if you consider that the Whitehorse dam represents 58 per cent of the total amount of energy Yukoners use throughout the year.
But climate change could actually turn out to be a boon for power generation in the territory. Changes to weather patterns could mean more precipitation for the Yukon, says Kavanaugh. Warmer temperatures cause increased evaporation from the ocean, bringing more rain and snowfall into the interior. And more rain and snowfall means more runoff in the spring to feed hydro dams.
The two monitoring stations will track changes in the weather in the medium term as well as capturing long-term climate changes. The equipment will be able to tease out oscillations in the weather from events like the El Nino and La Nina cycles, weather patterns that cause multi-year changes in temperature and precipitation patterns.
Such information allows researchers to more accurately monitor variations in weather that are a result of climate change. It also gives them the opportunity to track changes in nearby glaciers.
Last summer, hikers who passed through the Sloko Inlet trail near Atlin discovered that a normally fast-flowing riverway had been turned into a muddy field strewn with house-sized icebergs.
The area is normally fed by water from the Llewellyn Glacier, which has been retreating for the last 60 years, and the Juneau Icefield. Llewellyn Glacier has now retreated as much as eight kilometres, and when that happens water starts flowing in different directions. The shift in the flow of glacial meltwater last year meant that areas that were normally wet became dry while drier areas became flooded with water.
“The glaciers retreating is a response to long-term climate changes,” says Kavanaugh. “Most glaciers in the northern hemisphere are retreating – about 95 per cent of them.”
A study commissioned last year by Yukon Energy discovered that glaciers contribute up to 23 per cent of the total annual flow volume of the upper Yukon River (snowfall makes up 44 per cent and rain contributes the remaining 33 per cent). The Llewellyn Glacier makes up a dominant portion of the flow that comes from the region’s glaciers.
But Yukoners shouldn’t worry that a retreating glacier will mean a reduction in hydroelectricity, says Kavanaugh. “These are important reservoirs of water, but they’ll likely remain important reservoirs for some time. They’re not disappearing all that rapidly,” he says.
“Down the road that resource will change and we’ll see a few per cent decrease in that flow. But it will remain a resource for quite some time.” As the Llewellyn Glacier retreats, it will continue to provide water to the region for decades and probably even centuries, Kavanaugh adds.
The second stage of the project will add three more monitoring stations, two at different elevations near the Llewellyn Glacier and the other near the Wheaton Glacier just south of Whitehorse. The idea is to the keep the weather stations in place as long as possible, says Kavanaugh.
“The longer we can let them stay, the more valuable the record becomes because the local impact of these multi-year, decadal changes can really only be clarified with long-term monitoring.”
This column is co-ordinated by the Yukon Research Centre at Yukon College with major financial support from Environment Yukon and Yukon College. The articles are archived at www.taiga.net/yourYukon.