PLEA Network

20 July 2015, Science Daily, Changing climate lengthens forest fire season: Over a 35-year period, the length of forest fire seasons worldwide increased by 18.7 percent due to more rain-free days and hotter temperatures, according to research. The study examined weather data from 1979 through 2013 to determine how a changing climate impacts forest ecosystems. Over a 35-year period, the length of forest fire seasons worldwide increased by 18.7 percent due to more rain-free days and hotter temperatures, according to South Dakota State University professor Mark Cochrane, a senior scientist at the Geospatial Sciences Center of Excellence. The wildfire expert is part of a team of researchers led by W. Matt Jolly of the U.S. Forest Service Fire Science Laboratory that examined weather data from 1979 through 2013 to determine how a changing climate impacts forest ecosystems. “For things to burn, they have to have the proper conditions,” he explained. Four independent environmental factors increase the likelihood of wildfires — hotter temperatures, decreased relative humidity, more rain-free days and higher wind speeds. The researchers combined fire danger indexes from the United States, Canada and Australia with three global climate databases to create what Cochrane calls “an ensemble model.” They looked at the length of time and areas where conditions were conducive to fires. Their findings are published in Nature Communications. “Ecosystems are designed to withstand the normal climate situation, but we suspect that things aren’t normal anymore,” Cochrane said. On all the forested continents, except Australia, the fire seasons are getting longer, Cochrane explained. South America had the largest increase — 33 days in 35 years. In addition, the area affected by the longer fire season has doubled. Read More here