Expert explainer: Is Canada in for another extreme wildfire season?

As the 2024 wildfire months approach, climate scientists are bracing for what co
As the 2024 wildfire months approach, climate scientists are bracing for what could be another devastating year. (Wikimedia Commons/European Union, Copernicus Sentinel-2 image)
In 2023 Canada saw its most devastating wildfire season on record with 18.5 million hectares of forests burned, double the previous worst season in 1989, according to Natural Resources Canada.

As the 2024 wildfire months approach, climate scientists are bracing for what could be another devastating year. Geography and environment professor and chair Katrina Moser spoke with about the factors that lead to extreme wildfires and to emphasize the ways in which we can come together to tackle this urgent issue.

Western News: Why was last year’s wildfire season so catastrophic?

Katrina Moser: We now know that 2023 was the hottest year on record globally and Canada was no exception. That really contributed to the extreme wildfire season. When you have warm temperatures, you create very dry fuels. Last year El Nino was also a player in the warm temperatures, but the big factor of course is anthropogenic warming, which most people know as global warming.

Can you explain what anthropogenic warming is?

KM: Humans, by burning fossil fuels and through land clearance have increased the amount of greenhouse gases in our atmosphere, with carbon dioxide being the big one. Greenhouse gases allow shortwave radiation from the sun to come through and heat the Earth, which then re-radiates energy back into space as longwave radiation. However, greenhouse gases "trap" this outgoing radiation, further heating the Earth. By increasing emission of greenhouse gases such as CO2, we are causing the Earth’s temperature to rise. This is not a new finding; concern for a warming Earth related to increased greenhouse gases was first reported in the mid 1800s.

Is there a way to predict the severity of the upcoming fire season?

KM: Last year was exceptionally warm and caught scientists off guard; many were surprised by how warm it actually was.

"As scientists, we are always thinking about probabilities and are cautious about making predictions, but based on what we know about climate weather conditions for 2024, it looks like we should be prepared for another year like 2023.

One of the drivers of warm temperatures last year was El Nino which is predicted to end sometime late spring. That will likely keep temperatures above normal at least until May or June. There is a 50 per cent chance we could move into La Nina conditions late summer, which could cool things a bit. But we should be prepared for another difficult fire season.

What role do wildfires play in our ecosystems?

KM: If we look at the boreal forest, that’s an ecosystem that has evolved with fire and there are plants that have actually adapted to fire occurrence, for example, plants that need fire to release their seeds. Fire absolutely is a natural process and critical for boreal ecosystems.

Professor Katrina Moser, chair of the department of geography and environment However, we are seeing more intense and more severe fires burning more land area than ever before. We don’t know how ecosystems are able to respond to these extreme fire years.

And just to put it perspective, last year 18.5 million hectares were burned; over the last 30 years the average is 2.5 million hectares. Therefore, 2023 is way outside normal and if we have a couple years of that in a row, we need to think about what that will do. How will the ecosystems respond? We don’t have those answers yet.

Do wildfires impact our water resources?

KM: My research group is working on that problem right now and what I can say is that what we are finding in the very northern boreal forest around Yellowknife that if there is any impact by fire it’s short-lived. That makes sense because, as previously discussed, these ecosystems have evolved with fire. Looking at a lake that was severely burned, we saw minimal impact. But this work is not complete and needs more analysis.

What we do see is water systems are being impacted by warming temperatures in all kinds of different ways. For example, the Great Lake system only had 12 per cent ice cover in February, which leads to many effects. With less ice cover, the growing season for aquatic life is longer which can increase algal production and potentially lead to harmful algal blooms.

What message do you have for those wanting to make a difference?

KM: Many scientists are trying to find new, innovative ways to reduce greenhouse gas emissions. The impacts of climate change are serious, but if we let ourselves only focus on the negative it tends to have a paralyzing effect, and there is a lot we can still do.

We need everybody to get involved and engaged in this urgent matter. Three other Western faculty members and I have developed a free online course that braids together western science and Indigenous worldviews to try and help people learn about climate change, but more importantly take action. A lot of that is building connections with the land. If you have a strong connection with the land, you’re going to want to do something to protect that land.

The next offering of the course is in May, it’s 12 weeks long and we take 1,700 people per cohort.

Follow this link for more information on the course Connecting for Climate Change Action.