BOULDER, Colo. (CBS4) – A new study by researchers at the University of Colorado Boulder finds humans were responsible for igniting 97% of home-threatening wildfires between 1992 and 2015 in the United States. They also found these wildfires are amount to  about one-third of all firefighting costs.

(credit: San Miguel County)

Analysis also showed one million homes are within the boundaries of wildfires in the same time frame — five time more than previous thought. Researchers say nearly 59 million homes in the wildland-urban interface also sit within about 6/10 of a mile from a fire line.

“Our fire problem is not going away anytime soon,” said co-author Jennifer Balch, director of Earth Lab, a Cooperative Institute for Research in Environmental Sciences Fellow. “This provides greater justification that prescribed burns, where safe, can mitigate the risk and threat of future wildfires.”

She added we’re building more homes in the line of fire, and climate change is making communities more vulnerable to wildfire with warmer, drier conditions.