We examine multi-decadal temporal trends and spatial patterns of observed aerosol extinction coefficient and surface air temperature over the Sichuan Basin of Southwestern China. During the last 4 decades average temperature and daily maximum temperature over this region showed statistically significant cooling trends of about -0.1 K/10 yr and -0.14 K/10 yr, respectively. In the same period, significant increasing trends in pollutant emission and aerosol extinction coefficient are observed. Considerations of spatial patterns and temporal trends in the observed pollutant emission, aerosol extinction coefficient and surface air temperature records for the Sichuan Basin indicate a consistent picture of increasing emission of aerosol precursors, resulting in increasing aerosol amounts and extinction coefficient, negative radiative forcing and surface cooling. ¿ 2000 American Geophysical Union