Potential future changes in wildfire weather and behavior around 11 Canadian cities

Abstract

It is now well accepted that global greenhouse gas emissions will result in drastic changes in climate and patterns of natural disasters such as wildfires in Canada and across the globe. This study quantifies potential future changes in wildfire regimes around 11 Canadian cities with high socio-economic value and historically exposed with low to high wildfire hazard. Changes in extreme wildfire weather and behavior are calculated under 2 and 3.5 °C of global warming with reference to a baseline historical time-period of 1989–2019. Results provide statistically significant evidence of an extended wildfire season and more frequent weather conducive for wildfires around the cities. This will result in more intense wildfires with higher head fire intensities surrounding all cities. The city of Nelson (British Columbia) is found to exhibit highest wildfire magnitudes in both historical and future climates. The city of Thunder Bay (Ontario) is projected with most significant increases in the occurrence frequencies of extreme wildfires where 50-year HFI events are projected to become 18-year and 9-year return period events under 2 and 3.5 °C of global warming respectively. A statistically significant evidence of an increasing numbers of future wildfire events requiring significant suppression resources is also found. Results highlight the need for adapting buildings and infrastructure in the cities in the face of projected future changes in wildfires.