A major wildfire currently burning in central Canada has already released significant amounts of greenhouse gases into the atmosphere.
According to the Copernicus Atmosphere Monitoring Service, by early June 2025 the blaze had emitted approximately 56 million tonnes of CO₂ — a major carbon output in just a few weeks, second only to Canada’s record-breaking 2023 fire season.
To put that in perspective: Canada’s 2023 wildfires emitted around 640 million metric tons of carbon, roughly 2.4 gigatonnes of CO₂ — equivalent to several major industrial nations’ annual emissions.
Pollution in Wisconsin
The wildfire smoke plume has crossed the border into the U.S., blanketing Wisconsin in unhealthy air. The Wisconsin Department of Natural Resources (DNR) has issued an air quality advisory covering the entire state through July 31, at noon, due to escalating levels of fine particulate matter (PM₂.₅) linked to smoke.
Air quality monitoring shows PM₂.₅ levels across Wisconsin range between “Unhealthy for Sensitive Groups” (Orange) and “Unhealthy” (Red), with short-term spikes reaching “Very Unhealthy” (Purple) in some areas. The smoke has already dimmed the skies and created a haze across multiple counties, especially in the northern parts of the state.
The fire is attributed primarily to lightning strikes igniting dry fuel in Canada’s forests — a common natural ignition source exacerbated by extreme weather conditions. Once sparked, the blaze has spread rapidly across forests weakened by heat and drought.
Several interacting factors have created a perfect storm:
Record-hot, dry conditions heightened fire risk across Canada’s boreal zones.
The loss of traditional Indigenous fire management techniques, combined with modern fire suppression methods, has led to dense undergrowth and heavy fuel loads.
Warming climate trends have extended fire seasons and increased ignition likelihood, creating a feedback loop where wildfires release more CO₂, fueling further warming.
Climate and public health
Canada’s forests once served as crucial carbon sinks, absorbing about 30 percent of fossil fuel emissions annually. But massive wildfires — especially in 2023 and 2024 — have undermined that balance, releasing over 4 billion tonnes of greenhouse gases annually, turning delicate ecosystems from sinks into net emitters.
For residents of Wisconsin, the impact is immediate: hazardous air, strained health systems, and heightened risks for vulnerable populations. For the planet, these emissions accelerate climate change — a key driver of the increasing frequency and intensity of fires.