Clean Energy Canada | Media brief: The link between wildfires and other extreme weather and climate change
June 8, 2023
Clean Energy Canada is a clean energy think tank at the Morris J. Wosk Centre for Dialogue at Simon Fraser University. Through media briefs, we aim to provide useful factual and contextual information related to Canada’s clean energy transition. Please use this as a resource, and let us know if there are any topics that you would like to see for future media briefs.
The word “unprecedented” is already defining 2023’s wildfire season. By May, the area burned in Alberta exceeded a million hectares, putting the province on track to blow past the previous record set in 1981. And less than a week into June, wildfires in Eastern Canada have put tens of millions of North Americans under air quality alerts. Experts anticipate the country is destined for its worst ever wildfire year.
The season comes only a few years after B.C.’s 2017 and 2018 wildfire seasons, which were the worst two on record at the time. According to the Canadian Climate Institute, 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. In the insurance industry, nine out of the most costly 10 years in Canada ever have occurred since 2011.
Given the regularity of record-breaking events, the link to climate change is increasingly hard to ignore. But while the scientific link is clear, the connection is not always made explicit in media coverage of the weather events themselves. Extreme weather attribution is a growing field of science, dedicated to establishing the role that climate change plays in our changing weather patterns. It is now possible to attribute certain weather events to climate change with some confidence, with one analysis suggesting 71% of all studied extreme weather events were made more likely by climate change. And more recently, some analyses are even able to link damage from extreme weather to specific emitters.
The following brief summarizes some of the latest studies around the implications of extreme weather in Canada and the world.
- The Fort McMurray fire was 1.5 to 6 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 2 to 4 times more likely, while the area burned was 7 to 11 times bigger.
- The conditions that caused the devastating wildfires in southeastern Australia in late 2019 and early 2020 were made at least 30% more likely due to the effects of climate change.
- A study of 11 Canadian cities found that, under both 2°C and 3.5°C of warming, wildfire seasons would be extended, and weather conducive for wildfires would become more frequent. The City of Thunder Bay is among the most at risk, with one-in-50-year fire events projected to become 18-year and 9-year events under 2 and 3.5°C of global warming respectively.
- Climate change is expected to result in a 41% increase in the frequency of lightning worldwide, 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 contribution to poor air quality from wildfires is projected to increase more than tenfold by the 2050s under a high-emissions scenario, compared to the present climate in the Western U.S.
- Fine particulate pollution over the U.S. Pacific Northwest could double to triple during late summer to fall by the late 21st century. The historic fires and resulting pollution extremes of 2017 to 2020 could occur every three to five years under 21st-century climate change, posing challenges for air quality management and threatening public health.
- An increase in wildfire size, associated with climate change, in the Western U.S. has resulted in higher wildfire smoke plumes. The result is that aerosols from wildfires are injected into the atmosphere at greater heights, resulting in more widespread implications for air quality and long-range smoke transport.
- 37% of the area burned by wildfires in Western Canada and the United States between 1986 and 2021 can be traced back to emissions from 88 major fossil fuel producers and cement manufacturers.
- A Canadian study found that wildfire exposure was associated with slightly increased incidences of lung cancer and brain tumours.
- The decline in Arctic Sea ice as a result of climate change has affected regional circulation, which may have enhanced “fire-favourable weather conditions” in the Western U.S.
- A study showing seasonal pattern changes of atmospheric carbon monoxide indicated that transported wildfire pollution could potentially impact the health of millions of people across North America.
- Wildfires have also been linked to other extreme weather events, with one analysis finding that western U.S. wildfires “notably increase the occurrences of heavy precipitation rates by 38% and significant severe hail by 34% in the central United States.”
- Heatwaves will become longer and more intense because of climate change.
- The latest report from the United Nations’ Intergovernmental Panel on Climate Change found that 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 with 2°C, and 9.4 times with 4°C.
- The June 2021 heatwave in B.C.—which was the most deadly weather event in Canadian history, killing 570 people—was made 150 times more likely because of climate change and would have been “ virtually impossible” without human-caused warming.
- A new study found the 2018 northern hemisphere heatwave, which killed 74 people in Quebec, would have been “impossible” without climate change.
- Another study found that extremely hot days occur five times more often when compared to pre-industrial times as a result of climate change (where an extremely hot day is a one-in-a-thousand day event under pre-industrial conditions).
- 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
- Hurricane Fiona, which hit Atlantic Canada in 2022, was the most costly weather event ever to hit the region. Evidence suggests that climate change is making hurricanes more intense.
- One-in-100-year flood events in Toronto and Montreal are expected to become 1-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.
- Research investigating the 2013 Alberta floods found that climate change may have led to an increased likelihood of extreme rainfall.
- Another Canadian study, looking at the extreme flooding in Saskatchewan and Manitoba in 2014, found that climate change may have played a role in the significant increase in rainfall.
- 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 (where an extremely rainy day is a one-in-a-thousand day event under pre-industrial conditions). This is expected to climb to 65% if global warming reaches 2°C.