Canadian Fires Signal New Frontier in Climate Change

Weizineau, 57 years old, said that he’s experienced forest fires before. However, “it was in the forest; now it is all around the reserve. I have never been evacuated before.”

Scientists, firefighters and residents of remote communities such as Weizineau are experiencing a transformation of the vast green expanse of woods and wildlife into a tinderbox that can explode under the right conditions. They are seeing changes to the ecosystem that scientists link to a warming climate. 

Ecologists who’ve spent years in the field studying the forest say they see new swings of extreme rainfall followed by drought in the region, an expanding range of insect pests that are making forests more susceptible to fire, and shifts in the rich soils and permafrost that absorb and store carbon from the atmosphere. These changes are now combining with past fire management practices that some critics say have worsened this year’s conflagration.

The Canada fires forced tens of thousands of people to flee, sent choking plumes of yellow haze from Vermont to South Carolina and led health authorities to warn residents to stay indoors because of high levels of harmful particulates in the atmosphere along the entire Atlantic seaboard. 

As of Monday, 12.1 million acres had burned this season across 12 of Canada’s 13 provinces and territories. In Quebec alone, usually by this time in the fire season an average of 5,469 acres would have burned. This year, that figure has already surpassed 1.8 million acres, according to the Canadian government.

“The pattern of a rapid onset of drought, considerable wildfire and then air quality impacts associated with it are all consistent with global warming,” said Justin Mankin, a climate scientist at Dartmouth College, and co-lead of the drought task force at the National Oceanic and Atmospheric Administration. “This is a pattern we’ve seen in the West.” 

One creeping impact of a warming climate is the northward expansion of insects that can threaten the forests, ecologists say.

Kaysandra Waldron said colleagues at the Laurentian Forestry Centre were hiking in a grove of black spruce several hours from Quebec City on the North Shore area in 2021 when they discovered a large area of dead trees. The researchers believe the trees were killed by a combination of drought and infestation by spruce budworm, a caterpillar moth that usually attacks poplar and fir trees further south. The trees’ bud break is occurring earlier in the spring now, giving the larvae more food to eat when they emerge from winter, according to ecologists. 

“Normally you can see that insect in balsam fir stands, but now we are starting to see a large amount of black spruce that literally died in the last few years,” said Waldron, a research scientist for Natural Resources Canada.

Canadian forestry officials say that the spruce budworm is the most destructive insect of coniferous forests in North America, able to consume 85 percent of a tree’s leaves. 

In Western Canada, forests have faced a long-term assault from the bark-eating mountain pine beetle, which killed pine trees in a 45-million-acre area since the early 1990s through 2015, according to Canadian government statistics.

While insect-ravaged trees become fuel for fire, it is still unclear if the pine beetle infestation made forest fires worse there, said Allan Carroll, a professor of forest sciences at the University of British Columbia. Some studies suggest there has been no difference in the intensity of fires in beetle-infested regions, because the dead trees don’t provide a canopy for the fire to spread. 

This month’s fires across Canada are most likely burning hotter and longer today because firefighters stopped previous blazes, leaving bigger untouched areas for new fires to burn, Carroll said.

In British Columbia, Ellen Whitman, a research scientist for the Canadian Forest Service, spent last week trapped by a fire at her home on Vancouver Island. She’s hoping to eventually get back to a long-term forest site in the Northwest Territories.

As forest fires become more frequent, long-lived trees such as black spruce are being replaced with shorter-lived, faster-growing trees such as aspen and birch, according to a 2019 study Whitman published in the journal Scientific Reports.

This change in tree species is altering the animals that live there (woodland caribou replaced by deer and bison) and releasing long-sequestered carbon, sometimes turning the boreal forest into a carbon source, rather than a sink that helps keep global greenhouse gases in check. Old-growth trees and the deeper organic soils they grow on are able to store carbon longer than short-lived ones such as poplars. 

Forest fires in northern forests are starting to accelerate permafrost thaw, releasing methane and CO2 that worsen global climate warming. This has also been documented recently in Alaska.

Whitman lived through big fire seasons in western Canada, but she’s never experienced anything like this year. More than 13 times the average amount of land for this time of year has burned across Canada.

“All of this together is quite overwhelming,” Whitman said. “As a researcher and a scientist, we’ve been ringing the alarm bell about climate change and fire activity for years, but seeing years like this is personally quite difficult.”

The danger is also rising in places such as the U.S.’s Upper Midwest, where parts of Michigan and Wisconsin are seeing their highest fire danger risk on record, said Jim Wallmann, meteorologist with the National Interagency Fire Center in Boise, Idaho.

A major problem for Michigan this year is how widespread fires have been throughout Canada, which saps resources from provincial authorities that might be able to help U.S. colleagues. In the 1980s, authorities from Wisconsin, Minnesota and Michigan banded together to create the Great Lakes Forest Fire Compact, which eventually included the Canadian provinces of Ontario and Manitoba, to prevent fires and to share resources in the event of a fire. 

The international coalition is based on the notion that when one member is in trouble, they can use the resources of other members. But that notion is in question this season.

“A lot of us are in the same boat at the same time; that makes it difficult to share resources,” said Kerry Heckman, spokeswoman for Michigan’s Department of Natural Resources. “From my experience the compact is stretched more thin.”

Wildfires are part of the natural cycle of any forest, but it is the scale that is expanding as the climate warms, according to Mankin. 

Eastern North America still has more precipitation than the West, and he said eastern fires won’t burn as long. However, predicting how and when precipitation falls as snow and rain is becoming less clear, he said.

“Climate change is both unfolding rapidly in the form of large, systematic changes in droughts, floods, heat waves and the like, but it is also kind of unfolding slowly, in that we have our hands on the lever,” Mankin said. “It is our emissions of greenhouse gases that’s kind of determining how bad the climate problem becomes.”

Mandy Gull-Masty, Grand Chief of the Crees, said elders have warned her for decades about changes in wind and rain patterns, wildlife behavior and snowfall. 

“My members are really the canary in the coal mine and have been sounding the alarm on these issues long before we see the impacts in cities,” said Gull-Masty, who is from the northern Quebec Cree community of Waswanipi. “Because we are the front-line people with the forest on a daily basis.”

— Vipal Monga and Ben Kesling contributed to this article.

Write to Eric Niiler at [email protected], Paul Vieira at [email protected] and Jim Carlton at [email protected]