2009 BES Annual Meeting Presentation and Poster Abstracts
Role of Future Climate-induced Changes in Biogenic Emissions in Predictions of Future Ozone and Aerosols
Co-Authors: Wenyuan Chang
Abstract: Tropospheric ozone and aerosols are important for both air quality and climate change. An equilibrium terrestrial biosphere model, the BIOME4, is coupled with a previously developed unified general circulation model (GCM), the Goddard Institute for Space Studies (GISS) GCM II', that simulates coupled tropospheric ozone-NOx-hydrocarbon chemistry and sulfate, nitrate, ammonium, black carbon, primary organic carbon, and secondary organic carbon aerosols (SOA). The vegetation-chemistry-aerosol-climate coupling allows one to evaluate the extent to which global burdens, radiative forcing, and eventually climate feedbacks of ozone and aerosols are influenced by climate-induced changes in natural vegetation and consequently in biogenic emissions. We simulate differences between years 2000 and 2100. Equilibrium climate change over 2000-2100 is driven by changes in long-lived greenhouse gases, tropospheric ozone, and anthropogenic aerosols. The year 2100 concentrations of greenhouse gases as well as the anthropogenic emissions of ozone precursors and aerosols/aerosol precursors are based on the IPCC scenario A2. Global biogenic emissions of isoprene and monoterpene are estimated to be, respectively, 504 and 133 Tg C yr-1 with present-day climatological and land-cover conditions, 868 and 255 Tg C yr-1 with year 2100 climate but present-day land-cover, as well as 885 and 301 Tg C yr-1 with both year 2100 climate and natural vegetation. Climate-induced changes in natural vegetation are shown to be important for simulations of future tropospheric ozone and aerosols, especially for nitrate and SOA. The global burden of biogenic SOA is predicted to double between present-day and year 2100. We compare the direct radiative forcing by SOA with the forcing values of other anthropogenic aerosols.