AEROSOLS AND CLIMATE - ANTHROPOGENIC EMISSIONS AND TRENDS FOR 50 YEARS

A global inventory has been prepared for anthropogenic particulate emi ssions into the troposphere that covers the period 1990-2040. The inve ntory provides estimates for both primary particulate emissions and se condary contributions from atmospheric chemical reactions, particularl y of SO2. Using a conventional method, total worldwide anthropogenic e missions of particles <10 mu m diameter are estimated at 345 Tg/yr, ex cluding secondary NO3(-) and organics. Approximately 35% of the partic les entering the troposphere is airborne sulfate from oxidation of SO2 emissions. Emissions worldwide are dominated by fossil fuel combustio n, particularly coal, and biomass burning. These emissions are project ed to grow by 1.5 2.1 times in 2040, largely from fossil fuel combusti on. Growth is expected to be greatest in the developing countries, esp ecially India and China. Present anthropogenic emissions appear to be a small fraction of emissions from natural sources. However, the man-d erived component could become comparable to natural emissions by 2040. Increased haziness may enhance negative climate forcing both directly by increased radiative scattering and indirectly by modifying cloud a lbedo and cover. The forcing will be spatially non-uniform, superimpos ed on the forcing derived from greenhouse gases.