The link between wildfires, extreme weather, and climate change

The link between wildfires, extreme weather, and climate change is increasingly evident. With these events comes significant and costly implications for communities across the globe.

The following resource summarizes some of the latest studies around the implications of extreme weather in Canada and the world.

Costs of climate change

• Since 2010, the costs of weather-related disasters and catastrophic events have amounted to about 5% to 6% of Canada’s annual GDP growth, up from an average of 1% in previous decades, according to the Canadian Climate Institute. Climate-induced damages are set to slow Canada’s economic growth in 2025 by $25 billion annually, which is equal to 50% of projected GDP growth in that year.
• The Canadian Climate Institute records the cost of specific extreme weather events across the country in an online tracker. 
• In the insurance industry, nine out of the most costly 10 years in Canada ever have occurred since 2011.

Wildfires

• Climate change more than doubled the likelihood of extreme fire weather conditions in Eastern Canada in 2023, according to the World Weather Attribution Initiative.
• The 2024 wildfires across western Canada burned through 5.3 million hectares, about the size of Nova Scotia, making it the second-most destructive year in terms of area burned this century.
• In Jasper, B.C., Climate Central found that high temperatures in July 2024, around the time the fires started, were made twice as likely due to climate change.
• The devastating 2024 wildfire in Jasper resulted in the evacuation of 25,000 residents and visitors, the loss of 358 buildings, and over $880 million in insured damage.
• The 2016 Fort McMurray fire—Canada’s costliest disaster—was 1.5 to six times more likely because of climate change. Another study found that pressure vapour defects, which increased the fire risk, were made worse by climate change. 
• B.C.’s record-breaking 2017 wildfires were made one to four times more likely, while the area burned was 7 to 11 times bigger.
• Climate change is expected to result in a 41% increase in the frequency of lightning worldwide as we near the end of the century, with the western coast of North America listed as one of the areas most at risk. Lightning is the leading cause of wildfire ignition in B.C.
• The health costs of wildfires between June 4 and June 8 of 2023 are estimated to be $1.28 billion in Ontario alone.
• Natural Resources Canada estimates the fire protection costs could double in Canada by 2040 as we attempt to keep up with worsening risk. 

Heatwaves

• Heatwaves will become longer and more intense because of climate change, and Canada’s climate is warming twice as fast as the global average. 
• According to the European climate agency, the summer of 2024 was the Earth’s hottest on record. Thanks to the Government of Canada’s rapid extreme weather event attribution system, we know that the heat experienced across Canada this summer was made more likely due to climate change. 
• Canada’s Rapid Extreme Weather Event Attribution determined that the June 2024 heat wave that hit central and Eastern Canada was made two to 10 times more likely because of climate change. 
• The latest report from the United Nations’ Intergovernmental Panel on Climate Change found heatwaves that, on average, arose once every 10 years in a climate with little human influence will likely occur 4.1 times more frequently with 1.5°C of warming, 5.6 times more with 2°C, and 9.4 times more with 4°C.
• The June 2021 heatwave in B.C.—which was the most deadly weather event in Canadian history, killing 619 people—was made 150 times more likely because of climate change and would have been “ virtually impossible” without human-caused warming. Over the course of the heatwave, the number of wildfires rose from six to 175.
• A new study found the 2018 northern hemisphere heatwave, which killed 74 people in Quebec, would have been “impossible” without climate change.
• A rapid attribution analysis of the heatwave in Europe in June 2021, which saw temperatures of more than 45°C in parts of France, found it was made five times more likely because of climate change.

Floods and storms 

• Ocean warming caused by climate change fuels the formation of hurricanes and leads to hurricanes producing more rainfall, moving further inland, and undergoing rapid intensification more often. 
• This year’s Hurricane Helene was one of the deadliest hurricanes to strike the U.S. mainland in the last 50 years. According to a rapid climate attribution study done by the Lawrence Berkeley National Laboratory, climate change caused Hurricane Helene to drop 50% more rainfall in certain parts of the U.S. and made those record rainfalls up to 20 times more likely.
• Just two weeks later, Hurricane Milton rapidly intensified over the Gulf of Mexico to a category 5 hurricane. Researchers from World Weather Attribution found climate change made Milton 20% to 30% more intense. 
• Previous studies have shown climate change makes high temperatures in the Gulf of Mexico between 400 and 800 times more likely.
• Toronto’s 2024 summer floods brought nearly 100 centimetres of rain in just three hours, flooding many homes and businesses. These floods are estimated to have cost around $1 billion in insurable claims. Across Canada, one-in-50-year rainstorms could happen every 10 years by late century under a high-emissions scenario, according to a 2019 federal assessment. 
• The remnants of Hurricane Debby brought record-breaking floods to Quebec in the  summer of 2024, inundating 55 communities, leading to the most costly weather event in Quebec’s history, with insured losses amounting to $2.5 billion. 
• Hurricane Fiona, which hit Atlantic Canada in 2022, was the most costly weather event ever to hit the region.
• An atmospheric river weather system hit B.C.’s south coast in October 2024, causing record-breaking torrential rain, setting off a mudslide, overwhelming infrastructure, and killing at least three people. Research suggests that atmospheric river weather systems are increasing in frequency, intensity, and damage because of climate change.
• One-in-100-year flood events in Toronto and Montreal are expected to become one-in-15 year events by the end of the century as a consequence of climate change, according to a study by scientists from Western University and the National Research Council of Canada.
• Another study found that extremely rainy days are 18% more likely now than they were in pre-industrial times as a result of climate change. This is expected to climb to 65% if global warming reaches 2°C.