In 2023, Canada experienced its largest wildfire season in its recorded history. Approximately 18 million hectares of forest burned between May and September — roughly six to eight times the country’s long-term annual average.
The environmental impact was both terrestrial and atmospheric. Large areas of boreal forest converted to burn scar, altering habitat structure and carbon storage across affected regions. Smoke transported across North America produced acute PM2.5 exposure events in downwind population centers, including peak AQI readings above 400 in parts of the northeastern United States.
Within SIGNAL’s structure, the season is treated as a realization of interacting signals: annual burned area, wildfire carbon flux, atmospheric PM2.5 concentration, and population-weighted exposure days. Each can be measured independently and situated within longer-run distributions.
This entry records observed magnitude without attributing causality to specific policy choices or inferring long-term regime shift from a single season.
Selected metrics: • Burned area: ~18 million hectares • Long-term Canadian average: ~2–3 million hectares/year • Peak AQI (select U.S. sites): >400
