Increasing Wildfires

The frequency of large wildfires and the total area burned have been steadily increasing, especially in the Western United States. As the National Wildlife Federation reports, climate change is a major contributing factor dues to:

• Longer fire seasons. As spring runoff occurs earlier, summer heat builds up more quickly, and warm conditions extend further into fall. Western forests typically become combustible within a month of when snowmelt finishes. Snowpack is now melting 1 to 4 weeks earlier than it did 50 years ago.

• Drier conditions that increase the probability of fire occurrence. Summertime temperatures in western North America are projected to be 3.6 to 9 degrees Fahrenheit higher by mid-century, enhancing evaporation rates, while precipitation is expected to decrease by up to 15 percent.

• Availability of more fuel for forest fires due to warmer and drier conditions. Warmer conditions not only increase fuel loads directly, but are create conditions that are conducive to widespread beetle and other insect infestations, resulting in broad ranges of dead and highly combustible trees. Higher temperatures enhance winter survival of mountain pine beetles and allow for a more rapid lifecycle. At the same time, moderate drought conditions for a year or longer can weaken trees, allowing bark beetles to overcome the trees’ defense mechanisms more easily.

• Increased frequency of lightning. In the western United States a 1.8 degree Fahrenheit increase in temperature is expected to lead to a 6 percent increase in lightning. This means that lightning in the region could increase by 12 to 30 percent by mid-century as thunderstorms become more severe.

The overall area burned is projected to double by late this century across 11 western states if the average summertime temperature increases 2.9 degrees Fahrenheit, with Montana, Wyoming, New Mexico and Utah being hit particularly hard.

How Do Wildfires Threaten Wildlife?

Fire was once a healthy, natural part of our ecosystem, however climate change, a history of fire suppression, disease, and other pressures are causing more intensified firestorms, sparking more damage and putting wildlife more at risk. How is wildlife impacted by fires?

• They can’t escape.
• Their habitat is destroyed.
• Their habitat is dramatically altered.
• They undergo major stressors trying to recover.
• Bigger fires are changing the ecosystem balance.

Learn More

• Climate Change Resource Center: Wildfire, USFS
• Global Warming and Wildfires, NWF
• Increased Risk of Catastrophic Wildfires: Global Warming’s Wake-Up Call for the Western United States, NWF
• Western U.S. Wildfires and the Climate Change Connection Fact Sheet, WRI