The Yukon’s going to get warmer and wetter, says visiting hydrologist Sean Carey.
But there’s also going to be less water.
It all hinges on permafrost.
Simply defined as ground that stays frozen for more than a year, it restricts the movement of water, said Carey, speaking to a packed house during a Yukon Science Institute lecture at the Beringia Centre.
But as the temperature in the North rises — and it has risen seven degrees in the last century — the permafrost is starting to melt.
“It’s declining dramatically,” said Carey.
“And this will change the cycling of water.”
An aerial picture of northern tundra taken in 1973 was speckled with ponds.
The same shot, taken again in 1997, had a much smaller smattering.
“There are lots of ponds missing,” said Carey.
As the permafrost melts, the water sinks deeper into the earth and the ponds disappear.
But here’s where it gets tricky.
Melting permafrost is also creating more wetlands and bogs.
Large plateaus of peat held up by permafrost are disappearing into surrounding bogs, trees and all, as the melting continues.
In the last 53 years, 30 per cent of the permafrost has melted, said Carey, who’s watched peat plateaus measuring 40 metres shrink to 26 metres in just eight years.
“By 2030 to 2040 they’ll be gone, and the trees will be gone too, because they can’t survive in such a wet environment,” he said.
The glaciers are also disappearing, and this will have an effect on rivers, like the Yukon, he said.
While snowmelt feeds the rivers in spring, it is melting glacier water that feeds the rivers in late summer and fall.
When the glaciers melt more in summer than they grow with snowfall in winter, there is net loss, said Carey.
“And this is what’s happening.”
So while there seems to be lots of water now as the glaciers melt, once they’re gone rivers are going to become trickles, something Carey has already seen in some parts of the North.
“We are also losing two days of snow a year,” he said. “Since 1970, we’ve lost a month of snow.”
This too alters the amount of water flowing into northern rivers and lakes.
While scientists like Carey are working together under a network of Canadian researchers called IP3, Improved Processes and Parameterisation for Prediction in Cold Regions, to study the effects of climate change in the North, important players are missing.
Industry and development has a huge effect on hydrology, said Carey, pulling up a slide of a huge earthen sump holding drilling fluid. At first glance, it seemed to be relatively removed from the nearby river.
Then Carey pointed out a discoloured swath where the fluid is draining down to the water.
“The permafrost melted, and now it’s leaking into the river,” he said.
When forests are cleared and land is torn up, like the oilsands in Alberta, the hydrology becomes very different,” added Carey.
“And how we’re going to deal with ecosystem changes because of industry — we really have no idea.
“Lots of decisions in the North are based on good faith, but not necessarily good science, because it’s not there.”
Carey’s IP3 network is working with the Yukon Environment department and is meeting in Whitehorse until Saturday to discuss water issues in Canada’s mountains and North.
“University and government scientists, students, and water managers from territories, provinces, and industry across the country will present their research and new discoveries related to predicting the behaviour of water in Canada’s cold regions and predicting and minimizing related risks to resource industries, communities, and the environment,” said a news release.
“Yukon has experienced recent extreme weather and associated flooding. Snowfall during the winter of 2006/07 was the greatest on record, resulting in flooding of the Liard River.
“A warmer than normal 2007 summer produced significant glacier melt in the Southern Lakes, which, when combined with the record high snowpack and a wetter than normal summer, produced record high water levels which stayed above flood level for 67 days,” it said.
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