Searching for Climate Fingerprints on Fire Weather in North America

In recent years, the U.S. and Canada have seen record-breaking wildfire seasons. Fire weather – a combination of hot, dry, and windy conditions which promote extreme fire behavior – is becoming more frequent and severe in many parts of the world, including North America. While climate change is not a direct cause of wildfires, it has been linked to increasing fire weather trends which have made recent fires larger, more destructive, and harder to control.

Climate Central’s Climate Shift Index is a daily temperature attribution tool that quantifies the influence of human-caused climate change on local temperatures. The index is based on a categorical scale ranging from -5 to +5, signifying temperatures that have been made 5x less or more likely, respectively, due to climate change. While temperature is just one component of fire weather, it is the variable we can most-clearly and directly attribute increases to our actions.

Using the Climate Shift Index and the last two years of fire data from the National Interagency Fire Center and the Canadian Interagency Forest Fire Centre, we analyzed when and where wildfires began during anomalously high temperatures that had been made more likely due to human-caused climate change. In this talk, we will present our findings from the analysis, highlight conditions present at the start of recent notable fires, and discuss how the Climate Shift Index can be used to help us better understand the influence of human-caused climate change on wildfires.