资源环境科技发展态势分析平台

The relative importance of anthropogenic aerosol in decadal variations of historical climate is uncertain, largely due to uncertainty in aerosol radiative forcing. We analyze a novel large ensemble of simulations with HadGEM3-GC3.1 for 1850-2014, where anthropogenic aerosol and precursor emissions are scaled to sample a wide range of historical aerosol radiative forcing with present-day values ranging from -0.38 to -1.50 Wm(-2). Five ensemble members are run for each of five aerosol scaling factors. Decadal variations in surface temperatures are strongly sensitive to aerosol forcing, particularly between 1950 and 1980. Post-1980, trends are dominated by greenhouse gas forcing, with much lower sensitivity to aerosol emission differences. Most realizations with aerosol forcing more negative than about -1 Wm(-2)simulate stronger cooling trends in the mid-20th century compared with observations, while the simulated warming post-1980 always exceeds observed warming, likelydue to a warm bias in the transient climate response in HadGEM3-GC3.1.