The year 2025 has seen an exceptionally severe start to Canada’s wildfire season, with blazes of unprecedented scale and far-reaching consequences. Extreme wildfires have ignited across multiple provinces, consuming millions of acres of forest and forcing widespread evacuations. The smoke from these fires has not only choked Canadian skies but also drifted thousands of kilometers, triggering air quality alarms in the United States and casting visible haze over distant continents. As of mid-June, the fire season continues to escalate, with active blazes and total area burned already nearing historic highs — positioning 2025 as potentially one of the most destructive wildfire years on record. Scientists and officials are drawing direct links between the intensity of these fires and broader climate trends, warning that such “mega fires” may become the new normal.
Wildfire Context
By early June 2025, Canada’s wildfires were burning at a near-record pace. More than 3.2 million hectares (about 7.8 million acres) had already been scorched across the country — exceeding the full-season average. Around 200 active fires were burning, nearly half of them deemed “out of control.” Western and central provinces, including British Columbia, Alberta, Saskatchewan, Manitoba, and Ontario, have been especially hard-hit. In Alberta and Saskatchewan, multiple megafires exceeded 100,000 hectares (250,000 acres), with the Shoe Lake fire alone reaching over 500,000 hectares (around 1.2 million acres). Tens of thousands of residents, including many from Indigenous communities, were forced to evacuate. By June 9, Manitoba alone had registered over 21,000 evacuees.
As of June 13, the number of active wildfires has increased to 225, and total area burned now exceeds 3.7 million hectares — a pace that continues to outstrip seasonal averages. In Quebec, smoke from northern wildfires has raised concerns over air quality impacts on upcoming international events, including the G7 Summit, underscoring how Canada’s climate emergencies are now intersecting with global diplomacy.
This crisis is not isolated. In 2023, Canada experienced its worst wildfire season on record, with approximately 17 million hectares burned — more than twice the previous record. The 2024 season, though less catastrophic, still ranked as the second-worst in history, and 2025 appears to be following the same trajectory. Satellite detections of fire hotspots are at their highest early-summer levels since the satellite era began, second only to 2023. In recent days, the Canadian Interagency Forest Fire Centre had reported 1,874 wildfires ignited and 3.2 million hectares burned, already surpassing multiple provinces’ historical totals with the peak season still ahead.
International Fallout
By mid-May, smoke from Canadian wildfires had traveled across the Atlantic, carried by high-altitude winds and jet streams. It first reached southern Europe, and a second plume, larger and more concentrated, arrived in early June, drifting across Ireland, the UK, France, and Scandinavia. Initially suspended in the upper atmosphere, the smoke created an eerie visual phenomenon: orange-filtered light, muted sunrises, and milky skies. BBC meteorologist Matt Taylor’s 2023 analysis of Canadian wildfire smoke helps explain the eerie visuals seen again in 2025: smoke particles scatter blue light, allowing reds and oranges to dominate.
Smoke from Canadian wildfires — seen as grey plumes veiling parts of Western Europe in early June — was initially detected at high altitudes. NASA’s Aqua satellite tracked the plumes crossing the Atlantic, where they tinted skies and filtered sunlight across the continent. By mid-June, however, that smoke began to descend, prompting air quality alerts across Europe.
On June 10, wildfire smoke from Canada descended into the lower atmosphere over parts of Europe, causing a sharp deterioration in air quality. According to IQAir, cities like Vienna, Munich, Milan, Zurich, Geneva, Zagreb, and Ljubljana reported pollution levels ranging from “Unhealthy for Sensitive Groups” to “Very Unhealthy.” By June 11, several of these cities ranked among the most polluted in the world — not due to local emissions, but because of smoke that had traveled thousands of kilometers. While Saharan dust played a minor role in some areas, IQAir confirmed that Canadian wildfire smoke was the primary cause.
In North America, the impact was immediate: by early June, one-third of the United States — from the Great Plains to the East Coast — was blanketed by Canadian smoke. Air quality advisories were issued from Chicago to New York, and hospitals in cities like Minneapolis and Detroit reported a rise in respiratory complaints, especially among children. Schools kept students indoors, and residents were urged to avoid outdoor activity or wear masks . On June 12, parts of Minnesota reached the highest “maroon” level on the Air Quality Index (AQI) — the most severe designation — prompting urgent alerts from state health departments warning all residents to limit outdoor exposure.
In early June, NASA imagery captured a “long, unbroken river of gray smoke” stretching over 7,600 kilometers — from Canada to western Russia — blanketing vast stretches of the Northern Hemisphere. CAMS scientists described the transcontinental spread as “a reflection of the scale of the fires.” Even in locations untouched by flame, the evidence was clear: no region is insulated from climate-driven disasters.
Expert Insights
Scientists and public health experts are sounding the alarm about the broad and intensifying consequences of extreme wildfires. “Smoke knows no political boundaries — and neither does fire,” said Ecologist Dr. Lori Daniels of the University of British Columbia. She noted that Canada’s 2025 smoke patterns followed a vast diagonal trajectory, spanning continents. “We’re all struggling with this, not just in Canada and the United States, but worldwide.”
Dr. Paige Fischer, a professor of environmental sustainability at the University of Michigan, echoed this concern. She called the 2025 season “part of the new norm,” driven by hotter and drier conditions fueled by climate change. “The climate models are projecting that we’re going to have more frequent, more severe wildfires,” she warned — not just in boreal regions, but globally.
Public health officials are also worried. Fine particulate matter in wildfire smoke, especially PM₂,₅ — which stands for “Particulate Matter that is 2.5 micrometers or smaller in diameter” — can enter the bloodstream, aggravating asthma, heart disease, and respiratory issues. Environment Canada and the US CDC issued advisories urging vulnerable populations to stay indoors. Dr. John Balmes, a leading air pollution researcher UCSF, compared inhaling wildfire smoke to smoking cigarettes, stating that “if you’re healthy, occasionally breathing smoke may only cause transient symptoms,” but repeated exposure carries serious risks, stressing the health implications of even short-term exposure. Beyond the physical risks, many experts pointed to the growing psychological toll: orange skies and burning smells in places like the UK, far from any fire, are creating a shared sense of climate anxiety and helplessness.
Mark Parrington, a senior CAMS scientist, emphasized that only extraordinarily intense fires could inject smoke high enough to circle the globe. According to IQAir, some plumes reached 9,000 meters in altitude before descending and settling over Europe. Canadian fire officials, including Liam Buchart, confirmed that exceptionally dry conditions in late May and June — driven by climate change — were a major factor in the fires’ rapid spread and scale.
Wildfire scientists are also warning that the reactivation of “zombie fires” — blazes that smolder underground through winter — could prolong the crisis. According to analysis reported by the Financial Times, as summer brings a return to warm and dry conditions, smoldering underground fires are expected to reignite and spread, potentially resurfacing as active, flaming wildfires. These reawakened fires can sustain smoke emissions for months, well beyond the normal fire season, keeping air quality threats active even after visible flames subside.
Together, these voices paint a sobering picture: wildfires are no longer local disasters. They are cascading effects linked to this atmospheric instability that threaten lives, economies, and ecosystems well beyond their point of ignition.
Climate and Global View
The 2025 wildfires have become a case study in climate feedback loops: warming temperatures increase fire risk, while the fires themselves release vast amounts of carbon into the atmosphere, further accelerating climate change. Canada’s boreal forests, once seen as carbon sinks, are now emerging as major carbon sources. According to NASA, shorter winters and prolonged droughts are extending fire seasons — making them hotter, longer, and harder to control.
By early June, the fires had released 56 megatonnes of CO₂, second only to Canada’s 2023 fire season. The cumulative emissions from these two years now rival the annual output of some industrialized nations. While wildfire smoke can create short-lived cooling by blocking sunlight, its long-term climate impacts, particularly the release of carbon, are unequivocally harmful.
These fires have also strengthened calls for global cooperation. In June, Canada received firefighting aid from US states like Oregon and Idaho, as well as from Australia, which sent nearly 100 wildfire specialists, trained in direct suppression tactics and incident management. This kind of cross-border support is becoming increasingly critical as overlapping fire seasons stretch national emergency resources to the limit.
UN Secretary-General António Guterres described the current trajectory as “ever closer to the brink,” calling for a “fast, fair and funded” global energy transition. Experts agree that this must be matched by stronger mitigation efforts, such as reducing emissions, improving land use practices, as well as large-scale investment in resilience like early warning systems, air quality monitoring, and sustainable forest management.
From firelines in Alberta to sunset watchers in Somerset, the signs of climate disruption are everywhere. The 2025 wildfires are not an isolated incident — they are part of a pattern. And unless that pattern is broken, the costs will only grow. Experts say the choice is no longer whether to act, but whether we will act together.