Extreme Weather Toolkit: Wildfire

CM: Change in Fire Weather Days 2023 (EN)

More frequent hot, dry, windy conditions contribute to more wildfires that put people and ecosystems at risk. 

Wildfires can be an ecologically important disturbance. But human-caused climate change, poor land management practices, and sprawling development have increased both the availability of fuel and the frequency of weather conditions that spark and spread dangerous fires.

Wildfires can injure people, disrupt livelihoods, displace communities, lead to power outages, and take lives. Wildfire smoke is a serious concern for human health, crops, and livestock.

In the U.S., forest burned area has increased considerably since the 1990s.  

Both lightning-caused and human-caused fires have long occurred. But humans started 84% of wildfires from 1992 to 2012, tripling the fire season length and accounting for nearly half of all area burned over that period. 

Regardless of how fires start, more frequent hot, dry, windy conditions affect fuel availability, fire behavior (ignition, duration, and spreading), and can compromise suppression efforts. 

According to Climate Central analysis spanning the contiguous U.S. over a 50-year period (1973-2022), wildfire seasons are lengthening and intensifying, especially in the western U.S. 

  • Southern California, Texas, and New Mexico have experienced some of the greatest increases in annual fire weather days. Some areas now see around two more months of fire weather compared to 1973.

  • Parts of Texas, California, Oregon, and Washington now experience fire weather more than twice as often compared to 1973.

  • The eastern U.S. has experienced smaller increases in fire weather — primarily in parts of the Southeast and Northeast.

  • Even small increases in fire weather in the densely-populated East, with nearly 28 million homes in burn-prone areas, put more people at risk.

Human-caused climate change accounts for at least two-thirds of the rapid increase in fire weather in the western U.S. in recent decades. And the latest IPCC reports project more frequent fire weather conditions with increased warming.

Updated: April 2024