Fossil fuel-driven climate change made the extreme fire weather conditions behind this summer\u2019s ferocious wildfires in Ontario and the Northwest Territories roughly twice as likely to occur, concludes new research from Imperial College London\u2019s World Weather Attribution (WWA) initiative.\u00a0<\/p>\n
The 2026 wildfire season got off to a slow start, but \u201chas quickly intensified to dangerous levels through July\u201d thanks to \u201cmultiple occurrences of hot, dry weather since the end of June combined with significant lightning activity,\u201d write the authors of the just-released report.<\/p>\n
Based only on observational data, the extreme fire weather events seen in today\u2019s climate are now \u201cexpected to occur once every two to six years in the Northwest Territories, and every six to 15 years in Ontario,\u201d WWA said in a release.<\/p>\n
In a world without climate change, such extreme fire weather would occur \u201cless than once in 40 years,\u201d the report authors found.<\/p>\n
\u201cThe science is in: these fires have been made twice as likely by global heating. They are tearing through homes, communities, businesses, and the forests that economies depend on,\u201d UN climate secretary Simon Stiell said in a release. \u201cThe science backs up what people on the front lines already know: humanity\u2019s addiction to burning massive amounts of coal, oil, and gas is heating our planet, turning more of Canada\u2019s vast forests into tinderboxes, and spreading dangerous smoke far beyond the flames.\u201d<\/p>\n
Stiell added: \u201cThe world must move much faster away from polluting fossil fuels and towards clean energy, while protecting communities already living with the worst impacts, including the Indigenous communities on the front lines of these fires.\u201d<\/p>\n
Determined by the complex interplay between high air temperatures, low relative humidity, strong and\/or gusty winds, and dry vegetation, \u201cfire weather\u201d is a term used to describe the atmospheric conditions that help wildfires ignite and grow.<\/p>\n
When climate models are factored in, the extreme fire weather conditions that drove, and are driving, the fires in Ontario and the NWT have been made \u201cabout two or more times more likely\u201d than what would exist in a world without fossil fuel-driven climate change.<\/p>\n
Used in combination with observational data to allow researchers to determine a \u201cclear\u201d climate attribution signal, climate models produce a \u201cconservative\u201d estimate, report co-author Prof. Friederike Otto, professor of climate science at the Centre for Environmental Policy, Imperial College London emphasized at a media briefing.<\/p>\n
\u201cThe doubling might sound very little, but the impacts of that are really, really strongly non-linear, so a small change makes a huge difference for an ecosystem, and a community,\u201d Otto added.<\/p>\n
The 130th report produced by the World Weather Attribution initiative, now a decade into its work, aims \u201cto provide scientific evidence on the question of the role of human-induced climate change in the immediate aftermath of extreme weather occurring, or as in this case, while the event is still unfolding,\u201d Otto explained.<\/p>\n
As of Aug. 3, 3.8 million hectares have burned across Canada this season, well above the annual 30-year average of 2.7 million hectares from 1994-2023.<\/p>\n
The report identifies \u201cthe exceptionally rapid rate at which burned area accumulated over a very short period of time\u201d as a \u201cparticularly remarkable\u201d characteristic of this year\u2019s wildfire season.<\/p>\n
To quantify the role of climate change in exacerbating \u201crapid blow-ups\u201d of wildfire activity, as seen especially in northwestern Ontario this summer, researchers used seven-day accumulations of most extreme \u201cfire weather,\u201d as captured in a measurement known as the Daily Severity Rating (DSR).<\/p>\n
To evaluate the long-term conditions that result in widespread fire, such as that experienced in the Northwest Territories this summer, researchers used 30-day accumulations of the DSR.<\/p>\n
Using both observational data and climate models, they then compared conditions conducive to \u201crapid blow-ups\u201d and those that contribute to expansive fire behaviour to what would have been expected in a world without fossil fuel emissions.\u00a0<\/p>\n
The new assessment includes detailed comment on the impacts of that conjunction.<\/p>\n
\u201cSince the wildfires were primarily in remote and ecologically dense areas, First Nation communities were disproportionately affected,\u201d the authors write.<\/p>\n
Recalling that 13 communities in Ontario alone have been under evacuation orders this summer\u2014the majority of them small, remote First Nations\u2014the report cited the evacuations as a compound trauma, beginning in several cases with a disorganized official rescue response<\/a> that left some communities to manage their own evacuations.<\/p>\n Near total loss of property, combined with interrupted access to hunting grounds and traplines, layered atop a colonial history of prior displacement into residential schools and other forms of forced assimilation, are all conditions the report cites as making wildfire evacuations \u201can even more intense social and psychological stressor for Indigenous populations.\u201d<\/p>\n The report also expressed concern for the well-being of firefighters, many of whom are seeing increased physical and mental stress as fires become larger and more difficult to fight. Four Canadian firefighters, all of them involved in aerial<\/a> operations<\/a>, have died on the job so far this summer, note the report authors.\u00a0<\/p>\n Those risking their lives and well-being on the front lines of the firefight \u201care also at increased risk for post-traumatic stress, anxiety, depression, and suicidal ideation.\u201d<\/p>\n