Last updated June 18, 2017

Increased Wildfire Risk

Climate disruption has amplified the threat of wildfires by influencing the variables that start or fuel fires. Warmer temperatures and drier conditions increase the chances of a fire starting, or help a burning fire spread. Such conditions also contribute to the spread of the mountain pine beetle and other insects that can weaken or kill trees, building up the fuels in a forest. Climate change may also alter storm patterns, directly affecting the number of lightning-caused fires.

US trends

The National Climate Assessment states, “Hotter and drier weather and earlier snowmelt mean that wildfires in the West start earlier in the spring, last later into the fall, and burn more acreage.”[1]

  • Southeast: The southeastern US (including Texas and Oklahoma) leads the nation in number of wildfires, averaging 45,000 fires per year,[1] and this number continues to increase.[2][4] Increasing temperatures contribute to increased fire frequency, intensity, and size,[1] though at some level of fire frequency, increased fire frequency would lead to decreased fire intensity. Lightning is a frequent initiator of wildfires, and the Southeast currently has the greatest frequency of lightning strikes of any region of the country.[1] Increasing temperatures and changing atmospheric patterns may affect the number of lightning strikes in the Southeast, which could influence air quality, direct injury, and wildfires.[1]

Global trends

A global analysis of daily fire weather trends from 1979 to 2013 shows that fire weather seasons have lengthened across 29.6 million km2—or 25.3 percent—of the Earth’s vegetated surface, resulting in an 18.7 percent increase in global mean fire weather season length.[3]