After last year's extraordinary and record-breaking wildfire season, 2023 may have felt like a reprieve – at least in some parts of the country.
But last summer was still far above normal in many ways – and experts say the events offer clues about what's to come with climate change, driven largely by the burning of fossil fuels.
Here's a breakdown.
Large area burned
Given the extent of last year's fires, this year's wildfire season was not quite as devastating.
But it was worse than many people realize, said Yan Boulanger, a researcher with Natural Resources Canada.
According to the figures, the 2024 wildfire season is expected to be the second-worst wildfire season in terms of area burned since 1995, with more than 5.3 million hectares burned so far. That's far behind last year, when more than 15 million hectares burned.
“If we always compare it to last year as a reference, every other year won't be that bad. But I think we have to say it was a bad year,” Boulanger said in an interview.
The 2024 season is consistent with what wildfire researchers have observed over the past half century — an increase in area burned from decade to decade, he said.
Western Canada is the hardest hit
In contrast to 2023, when there were large wildfires across much of the country, this year most of them broke out in western Canada.
The costliest was in Jasper, Alta., where there were $880 million in insured losses.
About 70 percent of the total area burned was in British Columbia, Alberta, the Northwest Territories and Saskatchewan, officials said in a briefing last week.
Dry and hot again
Hot, dry weather is the cause of wildfires – and last year the conditions were right for them to spread.
The map below shows what's called the Fire Weather Index (FWI), which measures forest dryness (known as fuel) along with temperature, humidity, rainfall and wind speed.
In 2023, this map was dark red for most of the country. While it wasn't quite as dramatic this year, it was hotter and drier than usual, especially in western Canada.
“We are finding that the depth of the drought and the areas at high to extreme fire risk are very large,” said Lori Daniels, a wildfire expert and forestry professor at the University of British Columbia.
The number of fires is not increasing
The number of ignitions, also known as arson attacks, was not particularly high as in the previous year.
Overall, the number of human-caused fires has declined as awareness has increased and stricter restrictions have been put in place during peak fire danger periods, Daniels said.
“The message of prevention, making sure we don't accidentally start fires through recreational activities or industrial activities, that message is spreading,” Daniels said.
At the same time, researchers said they are concerned that extreme weather could lead to more “lightning bursts” – where hundreds or even thousands of lightning bolts strike in quick succession.
“If there are 100 fires at once, some of them will become fast-spreading fires in hot, dry, windy conditions,” she said.
Large source of emissions
The greenhouse gas emissions caused by last year's wildfires in Canada were on a whole different level – a recent study found that they produced more carbon than burning fossil fuels in all but three countries.
This year, Daniels said, the number will be significantly lower, just as the area burned will be smaller. In general, experts have expressed concerns that an increasing number of larger and more severe forest fires will contribute to further global warming.
“They burn deep into the ground, burning a buildup of organic material that literally took centuries to form,” Daniels said.
“We are releasing millions of tons of carbon into the atmosphere, which in turn represents a positive feedback with negative consequences.”
VIEW | Last year's wildfires released enough carbon to rival entire countries:
The 2023 wildfires in Canada released so much carbon that it could rival entire countries
If CO2 emissions from Canada's 2023 wildfires were compared to the national emissions of countries around the world, it would rank fourth behind the United States, China and India, says NASA atmospheric scientist Brendan Byrne.
When a season doesn't end
Climate change has contributed to wildfire season starting earlier and ending later, Boulanger and Daniels said.
Researchers assume that this trend will continue as the climate warms.
Dry conditions in northeastern British Columbia could cause fires there to continue burning throughout the winter, Daniel said. Last winter, more than 100 residual fires smoldered underground during the winter months.
“We have some fires that started in 2022 and 2023 that are still burning on October 1, 2024 and will still be burning in 2025,” she said.
Graphics by Wendy Martinez