Canada’s Wildfires Made Twice as Likely by Human-Caused Climate Change, Study Finds

Since late April, wildfires have been burning across Canada, blanketing the country and parts of the U.S. in unhealthy and sometimes dangerous smoke, in what Canadian wildfire officials have called the worst wildfire season ever recorded.

In a new study, scientists from the World Weather Attribution (WWA) Initiative examined the conditions that lead to the record series of wildfires and concluded that they were at least twice as probable due to human-caused climate change.

“In today’s climate, intense fire weather like that observed in May-July 2023 is a moderately extreme event, expected to occur once every 20-25 years. This means in any given year such an event is expected with 4-5% probability,” the study said. “Combining lines of evidence from the synthesis results of the past climate, results from historical and future projections and physical knowledge, we conclude that January-July cumulative DSR like that experienced in 2023 is at least seven times more likely to occur, and was 50% higher than it would have been without climate change; that peak fire weather intensity (FWI7x) like the 2023 event is at least twice as likely to occur, and around 20% more intense, than it would have been without human-induced climate change; and that this trend is projected to continue if warming continues.”

The study, “Climate change more than doubled the likelihood of extreme fire weather conditions in Eastern Canada,” was conducted by scientists from the Netherlands, Canada and the UK.

The area burned by this year’s wildfire season in Canada is bigger than Greece, reported The Guardian. More than 34 million acres have been burned — more than twice the previous record. 

“The word ‘unprecedented’ doesn’t do justice to the severity of the wildfires in Canada this year. From a scientific perspective, the doubling of the previous burned area record is shocking. Climate change is greatly increasing the flammability of the fuel available for wildfires – this means that a single spark, regardless of its source, can rapidly turn into a blazing inferno,” said Yan Boulanger, a research scientist at Natural Resources Canada and part of the study team, as The Guardian reported.

For the study, the scientists used the fire weather index, which measures wildfire risk using a combination of temperature, humidity, rainfall and wind speed. The conditions caused by climate change like higher temperatures, low humidity and less snow cover primed regions across Canada to be more prone to fires by drying out vegetation.

“This year, high temperatures led to the rapid thawing and disappearance of snow during May, particularly in eastern Québec, resulting in unusually early wildfires,” said Philippe Gachon, a researcher at the Université du Québec à Montréal, as reported by The Guardian.

Friederike Otto, senior lecturer at the UK’s Grantham Institute and co-founder of WWA, said the influence of climate change on this year’s Canadian wildfire season may be even greater than the figures in the report demonstrate because the estimates used by the researchers were conservative, CNN reported.

“It’s becoming evident that the dry and warm conditions conducive to wildfires are becoming more common and more intense around the world as a result of climate change,” said Clair Barnes, a Grantham Institute research associate and one of the authors of the report, as reported by CNN.

Québec has had the most area affected by the wildfires with 12.8 million acres burned so far this year — approximately 26 times more than the average through late August.

The wildfires have not only affected the air quality in Canada, but in U.S. cities like New York, Minneapolis, Chicago and Seattle.

Hundreds of fires continue to burn across the country, with one-fifth of them in the Northwest Territories. Thousands of people were ordered to evacuate there last week, with thousands more being evacuated in British Columbia as wildfire smoke floated down into the Pacific Northwest.

“Until we stop burning fossil fuels, the number of wildfires will continue to increase, burning larger areas for longer periods of time,” Otto said, as The Guardian reported.