A new study suggests the NWT’s Tibbitt to Contwoyto winter road can’t handle much more warmth, threatening the ice road’s ability to resupply diamond mines in future.
The road’s present operators, while welcoming additional research on the impact of climate change, disputed some of the study’s arguments. They argue the “direness” of the new study is overblown and the situation is more complex than the paper suggests.
Writing in the peer-reviewed Bulletin of the American Meteorological Society, researchers from three universities and the Geological Survey of Canada argued that a 2C increase in the world’s mean temperature could be “a tipping point for the viability of the Tibbitt to Contwoyto winter road, requiring at best costly adaptation and at worst alternative forms of transportation.”
Even if global warming doesn’t reach that point, the authors write, the road may still need to adopt a shorter operating season.
At the moment, the road allows trucks to haul heavy equipment and supplies between Yellowknife and three active diamond mines for an average of around two months each year. Without the road, which costs more than $20 million to build and operate annually, the mines would have to spend much more money bringing in equipment and supplies by air.
Eighty-five percent of the road crosses lake ice. The remaining 15 percent is a series of portages over permafrost peatland.
The study’s authors used for the first time a method of modelling lake ice, rather than a combination of ice thickness records and climate trends, to project how the road’s operating season would evolve in 15 different scenarios.
Arguing a 50-day season was the lowest that could be considered “viable,” the study found that most seasons modelled remained viable with a 1.5C global temperature increase, but that viability slipped noticeably at 2C and the road had barely any chance of getting to a 50-day season at 4C.
“These findings suggest that, for an average year, an increase from 1.5C to 2C is the tipping point at which costly adaptation is required,” the report stated. (By some estimates, the global mean temperature rose by around 0.5C in the past 20 years.)
The Arctic is warming at a faster rate than other parts of the planet, meaning a global temperature increase of 4C doesn’t necessarily mean the NWT would be 4C warmer. The study suggests a global mean rise of 4C would be more likely to make Tibbitt Lake 11.5C warmer in a given December than it is now, and 6C warmer in March.
“With these regions warming two to three times faster than the global average, climate change threatens the long-term viability of these important seasonal transport routes,” the study declared of the Tibbitt-Contwoyto road and others like it.
Portages are the problem
At the joint venture that builds and maintains the road, the study was greeted with a degree of skepticism.
Mike Lowing, a Rio Tinto employee who serves as Tibbitt-Contwoyto’s director of winter road operations, said Cabin Radio’s call was the first he had heard of the study. He and engineers working on the road had not been contacted by researchers, he said.
On reviewing the paper, Lowing said he welcomed additional research into the impact of climate change on the road but felt some of the study’s emphasis was misplaced.
“Should we be concerned about global warming? Yes, every northerner should be. It is a long-term journey. I’ve spent all my life in the North and I see changes,” Lowing told Cabin Radio.
“It is always in the background. We do worry about it. But it’s far more complex.”
Lowing in particular highlighted a problem the study’s authors themselves acknowledged: their model of lake ice does not assess what would happen to the 15 percent of the road taken up by portages.
“We worry more about the portages going before the ice does,” said Lowing.
“We go over 55 portages, and the bulk are in the south section where you get the warmer weather. Portages remain our vulnerable point.”
The joint venture between the mines that builds the road has launched research of its own into ways of better preparing portages for warmer weather. Techniques have been devised to strengthen lake ice when necessary, Lowing said.
Lowing did agree with the study’s finding that storms were likely to cause more problems for the road’s operators as the climate changes.
“A poleward shift in extratropical cyclone activity is projected to result in increased atmospheric moisture and greater winter precipitation over the northern half of North America,” the study’s authors wrote. “This indicates the clear future potential for an increase in blowing snow and hazardous blizzards that further threaten the operational season.”
Lowing said: “The storms seem to be more significant. This season, we didn’t have as many storms as last year, but they were longer and had more snow volume, which made it harder to clear out.”
‘A shift away from ice roads’
Lowing acknowledged the winter road had seen “catastrophic” seasons in the past – such as 2006, when one lake’s ice disintegrated so quickly that trucks were trapped at mine sites – but said the mines had changed how the road is run in response. He disputed the “sense of direness” he felt from the study’s wording.
“We could have run this winter road easily for another two weeks after we closed here at the end of March,” he said of this year’s season. “It could have been a 10-week road, easily.
“It’s the demands of the partners that dictate a lot of our loads. This year we punched just a tad under 6,200 loads. That’s one of the lowest loads we’ve had since 2013. We see our load counts going down, which takes pressure off the road as well.”
All three active diamond mines are scheduled to close by the mid-2030s with nothing yet lined up to replace them, meaning the winter road could be significantly scaled back or wound down entirely before climate change reaches the tipping point envisaged by the study. However, similar winter roads elsewhere in the North will almost certainly remain in operation until they are no longer viable.
“It’s not a top secret that mines ebb and flow,” said Lowing.
Ultimately, Lowing said, both the study and the gradual impact of climate change gave support to the idea – being pursued vigorously, if without cash, by the territorial government – of building an all-season road through the region from the Ingraham Trail to Nunavut.
“If we look at how to reduce risk, that is fundamentally a shift away from ice roads,” he said.
“Ice roads are a pain because we’re going to spend up to $23 million this year and it all floats away when it’s done. A permanent road, you can run materials and fuel for the most part year-round. You’ll still need a winter road in the northern section but that can be run much longer because of the colder weather. It’s a very different weather pattern than in the south section and there are fewer portages.
“Right now, the road varies by year. Anecdotally, I don’t think I can tap on anything that says things are shifting. But that’s always in our background.”