AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Latitudinal Shifts in Wildfire Activity and Smoke Concentrations in Response to 21st Century Climate and Land Cover Change over the Western US
YANG LI, Loretta Mickley, Jed Kaplan, Pengfei Liu, Harvard University
Abstract Number: 305 Working Group: Biomass Combustion: Emissions, Chemistry, Air Quality, Climate, and Human Health
Abstract Recent studies have projected increasing trends of wildfire activity under a warmer and drier climate in the western US, with implications for air quality due to increasing smoke particulate matter (PM). However, there exists large uncertainty in these projections, and not all studies have taken changing land cover or land use into account. Here we implement a coupled modeling approach to assess the impacts of future changes in climate and land use/ land cover on wildfires, and to investigate the consequences for surface air quality. We rely on a process-based fire model linked to a dynamic global vegetation model (LPJ-LMfire) and a global chemical transport model (GEOS-Chem) to examine smoke trends across the 21st century for different Representative Concentration Pathways (RCPs) in the western US. Under a scenario of moderate climate change (Representative Concentration Pathway 4.5, or RCP4.5), we find that increasing fire activity in the western US enhances the burden of smoke fine particulate matter (PM2.5) across the West, with increases of ~54% by the late-21st century during the fire season (July-September). In the worst-case scenario (RCP8.5), smoke PM2.5 concentrations across the West nearly double by 2100 during the fire season. RCP8.5 also shows large, northward shifts in living biomass and thus dry matter burned, leading to especially increased fire activity in northern states, such as Montana and Wyoming. Regions east of the Rocky Mountains also experience enhanced fire activity.