What were the causes and consequences of our worst wildfire season to date?

Author: K. Coco Zhang

The 2023 wildfire season in Canada shattered records in both scale and intensity. Starting in Alberta during late spring, wildfires rapidly spread across Quebec, Nova Scotia, the Northwest Territories, and British Columbia over the summer, becoming one of the most devastating fire seasons in Canada’s history.

“The area burned was approximately 15 million hectares, which was by far the highest since accurate fire mapping and record-keeping began in 1972. In fact, the area burned in 2023 was over twice that of the previous record in 1989,” Piyush Jain, a research scientist at the Canadian Forest Service in Natural Resources Canada, said in an interview with //The Tribune//.

In total, about 6700 reported wildfire ignitions occurred in 2023, with 59 per cent of them believed to be caused by lightning strikes. 

“If lightning strikes occur near a fire, then it is likely to be assigned as a lightning-caused fire. If there’s no lightning, then the fire is presumed to be human-caused,” Jain explained. “Human-caused fires do not mean that they were intentionally lit. Most of them occur accidentally or through industrial agricultural activity on the landscape.”

Lightning-caused wildfires accounted for 93 per cent of the total area burned, with just four days—May 13, May 27, June 1, and July 5—responsible for 30 per cent of the total annual area burned. Although human-caused fires only made up 7 per cent of the area burned, they caused a disproportionately large number of evacuations and destruction of structures because they generally started close to populated areas.

Canada’s escalating wildfire crisis is driven by a combination of climate change, forest management practices, and expanding human settlements in fire-prone regions. These factors not only increase the likelihood and intensity of fires but also amplify their environmental, economic, and health-related consequences.

Climate Change and Its Impact on Wildfire Risk

Climate change is driving a fundamental shift in temperatures and atmospheric moisture levels, making Canadian forests more prone to frequent fires. 

According to Jain, climate change contributes to longer and more intense fire seasons by creating hotter and drier conditions, which increase the flammability of forests. Additionally, climate change has contributed to the spread of invasive species such as the pine beetle, which has destroyed vast areas of trees. The dead trees burn more easily since they’re drier, turning forests into readily ignitable fuel for wildfires. 

“Climate change significantly increased the likelihood of large-scale burn areas across most of Canada, and the likelihood was over twice as high in the east, such as Quebec, and southwest, such as British Columbia,” Jain noted.

Taken together, these changes in weather patterns and ecosystem dynamics suggest that wildfires will become a year-round threat, with municipalities facing increasingly severe fires, including those outside of traditional fire seasons. 

The Role of Forest Management and Urban Expansion

Alongside changing climate conditions, forest management practices have also contributed to wildfire risks. When they occur at normal levels, wildfires are actually beneficial for forest ecosystems. When trees like pines and spruces burn, they release seeds, return nutrients to the soil, and restart the cycle of forest growth. This natural process helps thin out the buildup of dry forest fuels, such as twigs, leaves, brush, trees, and deadwood. 

However, Canadian and American forest management has adopted fire exclusion—the practice of actively excluding any fire from a specific area—which has disrupted this cycle of smaller burns. As a result, when fires do occur, they burn with greater intensity and speed. 

Moreover, urban sprawl into the wildland-urban interface—areas on the outskirts of communities where urban development meets forested regions—has further increased wildfire risk. Placing homes and infrastructure directly next to natural vegetation creates more potential ignition points from human activity. This close proximity to wildlands increases the likelihood of wildfires impacting homes and communities, resulting in greater damage to property and lives when a fire does occur.

“There are numerous factors that are driving the migration of people into the wildland-urban interface, but a lot of it has to do with housing affordability,” said Clare Milliken, a McGill alumnus with a Masters of Urban Planning, in an interview with //The Tribune//. “Instead of building cities up in the middle, new housing is often built on the outskirts of these cities, where it tends to be more affordable.”

In addition to affordability, the appeal of living among nature and wildlife has driven people to these high-risk areas.

“People are drawn to living among wildlife and trails, particularly in Western Canada,” Milliken said. “The lifestyle is attractive to people.”

Despite the heightened wildfire risk in the wildland-urban interface, approximately 13 per cent of the Canadian population lived in the wildland-urban interface as of 2021. Efforts to limit this expansion often face resistance, driven by factors such as Canada’s ongoing housing crisis and the urgent demand for rapid housing development. 

Environmental and Health Impacts

Unlike low-intensity fires that may promote nutrient recycling in ecosystems, intense fires destroy soil quality and reduce its ability to retain water. This damage leads to long-term ecological problems and continues a vicious cycle where forested areas are even more susceptible to future fires. Moreover, wildfires can dramatically alter ecosystems, resulting in habitat loss for species such as the boreal woodland caribou. 

In terms of water security, wildfires alter natural water flow and damage aquatic habitats, leading to water contamination from excess nutrients, sediments, and heavy metals. This can pose challenges for water treatment facilities processing drinking water for safe human use. The increased load of contaminants can also overwhelm treatment plants, raising the risk of treatment failures. 

Furthermore, common post-fire events such as flash floods and debris flows can significantly affect water quality and infrastructure. In the long term, increased wildfire activity and extreme weather events may threaten the capacity of watersheds to consistently supply clean water to communities and ecosystems. 

On a global scale, the burning of biomass—a renewable energy source that comes from organic materials like plants and animals—during wildfires significantly contributes to atmospheric carbon dioxide levels, further exacerbating climate change.

“The amount of biomass burned was five times more than previously, and aboveground biomass that was burned is directly related to carbon emissions,” said Flavie Pelletier, a PhD student in McGill’s Department of Natural Resource Sciences, in an interview with //The Tribune//.

Notably, the wildfires of 2023 alone produced the highest carbon emissions on record for Canada, accounting for 23 per cent of the world’s total carbon emissions.

“Forests are basically reservoirs of carbon. Trees absorb carbon from the atmosphere as they grow, but they can also emit carbon, meaning the carbon that was stored in the tree is being released back into the atmosphere,” explained Brendan Byrne, a senior data scientist at Qube Technologies, in an interview with //The Tribune//. “Our study found that the amount of carbon emissions from the 2023 Canadian wildfire season was 647 teragrams, which was much higher than previous years.” 

These emissions are comparable to the total annual emissions of India—the third-largest contributor to global carbon emissions—and play a significant role in global warming, which in turn intensifies the risk of future wildfires, creating a positive feedback loop.

The health impacts of wildfires are equally concerning. Smoke from the fires, which can travel vast distances, led to hazardous air quality across Canada and beyond. In 2023, smoke from fires in Northern Quebec blanketed New York City, temporarily giving the city the worst air quality in the world.

“The summer of 2023 was very smoky. People across Canada experienced above-average levels of smoke, and this is particularly true in the Northwest Territories, British Columbia, Alberta, and Quebec, because of their proximity to the fires,” Jain said.

Vulnerable populations, including the elderly and people with pre-existing conditions such as asthma, face heightened risks. Additionally, poor air quality forces people to stay indoors, limiting outdoor activities. 

Beyond physical health, the emotional toll on individuals—especially those in Indigenous communities—has been profound. 

“The impact of wildfires on mental health is often overlooked. These fires have frequently caused mass evacuations. The highest amount of evacuations happens in Indigenous communities, which are usually remote. The psychosocial impact of having to be evacuated from your community almost yearly is a huge deal,” Milliken explained. “Because of the [extreme nature] of the events, emergency staff working in high-pressure situations also face a ton of burnout.”

Economic Impact

The national expenditure on wildland fire protection has surpassed $1 billion CAD annually for six of the past 10 years, with costs increasing by approximately $150 million CAD per decade since 1970. These costs cover direct response and recovery efforts, including property damage, evacuations, and suppression efforts, as well as indirect costs such as business closures and unemployment.

Individual wildfires can cause extensive damage, with some fires destroying hundreds or even thousands of buildings, leading to multi-billion-dollar costs in both direct and indirect damages. The 2016 Fort McMurray wildfire alone cost the Canadian government an estimated $9 billion CAD, making it the nation’s most expensive natural disaster and largest evacuation on record.

The Path Forward

Canada’s 2023 wildfire season starkly illustrates the challenges posed by climate change and urban sprawl, underscoring the urgent need for action to reduce the risk and impact of future wildfires.

“Climate models predict that fire weather in Canada will become more extreme,” Jain said. “However, this is highly variable. It does not mean every year will be worse than the last, but it does suggest a general upward trend in the frequency and intensity of fires on the landscape.”

Although we cannot prevent wildfires entirely, the key lies in better preparedness, enhanced response strategies, and long-term prevention efforts. One positive step forward is the Canadian government’s increased funding for initiatives directly related to wildfire management. Recent investments in fire detection technology, early warning systems, and firefighting equipment aim to improve response times and reduce long-term damage.

“Knowing what happens in almost real-time allows you to intervene sooner. If we know an area has burned, we can likely cut and salvage trees in areas of low burn severity [more promptly]. This is crucial for wildlife conservation purposes,” Pelletier said.

These investments in firefighting infrastructure are critical for both protecting communities and conserving the natural environment. 

However, the current home insurance system in high-risk areas is becoming increasingly unsustainable. As wildfires grow more frequent and severe, insurance premiums for homeowners in fire-prone regions are expected to rise sharply, making coverage unaffordable for many. Therefore, governments and insurers must explore innovative solutions, such as creating dedicated wildfire insurance funds or offering incentives for fire-resistant building practices, to ensure residents in high-risk areas are adequately protected without facing prohibitive costs. 

In addition to addressing immediate wildfire risks, Canada must rethink land-use policies, particularly in the wildland-urban interface. Sustainable urban planning can help limit the expansion of human settlements into fire-prone areas, reducing the exposure of homes and infrastructure to wildfires. Meanwhile, forest management strategies should focus on restoring the natural fire cycle, including prescribed burns—intentionally lit, small, controlled fires—to mitigate wildfire risks and reduce the intensity of future wildfires. 

While the path forward is challenging, it is clear that proactive measures, such as increased funding for wildfire infrastructure, rethinking insurance models, and adopting sustainable urban planning practices, are crucial in mitigating the long-term risks of wildfires. By taking these steps, Canada can better protect its communities, natural resources, and future generations from the devastating impacts of wildfires.