Climate and Energy Action Plan (CEAP)

CLIMATE TRENDS & PRO JECTIONS | CITY OF ASHLAND, OREGON | FINAL REPORT | 28 Wildfire Warmer and drier conditions have resulted in more frequent large fires and an increase in the total area burned across the western U.S. during the last 30 years (Dennison, Brewer, Arnold, & Moritz, 2014) and over the pas t century (Littell, McKenzie, Peterson, & Westerling, 2009) . The length of the fire season in the western U.S. has also increased due to warmer temperatures and earlier snowmelt (Westerling et al. 2006 , Jolly et al., 201 5). In the ecoregion encompassing the Cascade, Sierra, and Klamath Mountain ranges, the number of large fires increased at a rate of 0.6 per year and the beginning of the fire season was 1 day earlier per year over the period 1984 -2011 (Dennison et al., 2014) . Such trends are expected to continu e under future climate change (Figure 20). The probability of very large wildfires is projected to incre ase by at least 30% by the end of the century in the western U.S. (Stavros, Abatzoglou, Larkin, McKenzie, & Steel, 2014) . One study estimated that the Pacific Northwest regional area burned per year would increase by roughly 900 square miles by the 2040s (Littell et al., 2013) . In the region west of the Cascades, including the Klamath Mountains, the fire return interval, or average number of years between fires , is projected to decr ease by about half from about 80 years in the 20th century to about 40 years in the 21st century assuming a fire suppression management regime (Sheehan, Bachelet, & Ferschweiler, 2015) . Figure 20. Increases in area burned that would result from the regional temperature and precipitation changes associated with a 2.2°F globa l warming across areas that share broad climatic and vegetation characteristic s. Local impacts will vary greatly within these broad areas with sensitivity of fuels to climate (Mote et al., 2014) .