Atmospheric aerosols play a key role in the Earth’s system by interacting with atmospheric chemistry, radiation, clouds, and biogeochemistry, thereby affecting air quality, climate, hydrological and biogeochemical cycles. However, current Earth system models (ESMs) are still associated with large aerosol biases. In this talk, I will introduce the Modal Aerosol Module (MAM) and aerosol-cloud interaction schemes adopted in several leading ESMs, which I have been playing a key role in developing since 2006. I will then highlight two main aspects of my work with the goals to reduce the uncertainties of aerosol radiative forcing and climate impacts: (1) continuous improvement of the MAM related to black carbon, brown carbon, dust, wildfire smoke, nitrate, and stratospheric volcanic aerosol; and (2) ice nucleation and secondary ice production in mixed-phase clouds, and their implications for cloud feedbacks and climate sensitivity. Finally, I will talk about some remaining challenges in aerosol modeling in ESMs.