Climate change will increase risk of wildfires and extend fire season, study confirms

Wildfires are among the nation’s most destructive natural disasters, threatening lives, destroying homes and infrastructure, and creating air pollution. In order to properly predict and manage wildfires, managers must understand wildfire risks and allocate resources accordingly. A new study brings scientific expertise to this effort.

In the study, published in the November issue of the journal The future of the Earth, Researchers from DRI, Argonne National Laboratory and the University of Wisconsin-Madison teamed up to assess future fire risks.

They examined the four fire danger indices used across North America to predict and manage wildfire risk to see how risk correlated with the magnitude of wildfires observed between 1984 and 2019. They then looked at how wildfire risk had changed based on projected future climate, finding that climate change is likely to lead to both wildfire potential and a longer wildfire season .

“We use several of these fire danger indices to assess fire risk in the contiguous United States,” said Guo Yu, Ph.D., research assistant professor at DRI and lead author of the study. . “But previous studies have only looked at how climate change would change wildfire risk using one of these, and only a few studies have looked at how wildfire risk has translated by the size or characteristics of actual wildfires. We wanted to rigorously evaluate both in this paper.”

Fire risk indices use information about weather conditions and fuel moisture or how dry ground vegetation is. The most commonly used fire hazard indices in North America are the USGS Fire Potential Index, the Canadian Wildfire Weather Index, and Fire Release Component Indices. energy and combustion of the national fire risk assessment system.

First, scientists used satellite remote sensing data from 1984 to 2019 to see how potential fire risk correlated with ultimate wildfire size for more than 13,000 wildfires, excluding burns. controlled. They found that when wildfire risk was higher, wildfire sizes tended to be larger, and this relationship was stronger over larger areas.

By integrating fire danger indices with future climate projections, the study found that the extreme risk of wildfires will increase by an average of 10 days across the continental United States by the end of the century, largely due to increasing temperatures.

Some regions, such as the southern Great Plains (including Kansas, Oklahoma, Arkansas, and Texas), are expected to experience more than 40 additional days per year of extreme wildfire risk. A few small regions are expected to experience a decrease in their annual wildfire risk season due to higher precipitation and humidity, including the Pacific Northwest and Mid-Atlantic coasts.

In the Southwest, the extreme wildfire season is expected to increase by more than 20 days per year, with most occurring in spring and summer. Longer fire seasons extending into the winter months are also expected, particularly in the coastal plain of Texas and Louisiana.

“In a future warmer climate, we can see that fire risk will be even higher in winter,” Yu said. “This surprised me because it seems counterintuitive, but climate change will change the landscape in many ways.”

The study authors hope the study will help fire managers understand the magnitude of potential wildfires so they can prepare accordingly, as well as understand how fire seasonality will change and will expand under a changing climate.