991193 - Present and Future Wildfires Caused by Dryness in a Changing Climate

Wildfire activity in the western United States became more frequent and intense in recent decades. The frequency of wildfires in present and future climate is of great concern for public health. Because of continuously rising surface temperature and lack of precipitation that exacerbates soil moisture deficits and reduces relative humidity, enhanced fire intensity, and total burned area have been observed over the western United States. As Earth system models predict intensified soil moisture deficits in much of the western United States, it is essential to evaluate future wildfire impacts on regional climate with dryness and to provide fire risk for decision-makers. Our study will utilize the Weather Forecast Research (WRF) model to evaluate the impacts of current (2003–2010) and projected future (2050–2059) wildfires on regional climate including temperature and precipitation over the western United States during the fire season (April–November). Fire events data will be collected in the present years and compared with modeling outputs utilizing the Representative Concentration Pathway 8.5 (RCP8.5) scenario defined by the Intergovernmental Panel on Climate Change in the present and future years. We will subsequently use the standard RCP8.5 scenario downscaling in WRF simulations for the future and compare the resulting fire events in the present and future years. Our results will provide estimates of future temperature and humidity to cause wildfire for policymakers and governmental services to inform management decisions.