The paper by U. Lohmann and J. Feichter reviews the global indirect aerosol effects on the climate system, focusing on the multitude of ways in which aerosols influence cloud characteristics. While the cloud albedo enhancement (Twomey effect) of warm clouds has received significant attention, the authors discuss various other effects, including the cloud lifetime effect, semi-direct effect, and changes in the hydrological cycle. They highlight the need for better representation of these effects in global climate models and the uncertainties in current estimates. The review covers observational data, global climate model simulations, and the impact of aerosols on different types of clouds, such as water clouds, mixed-phase clouds, and ice clouds. It also discusses the aerosol-induced changes in the surface energy budget and their implications for precipitation patterns. The authors emphasize the complex interactions between aerosols and the climate system, which require further research to fully understand and model.The paper by U. Lohmann and J. Feichter reviews the global indirect aerosol effects on the climate system, focusing on the multitude of ways in which aerosols influence cloud characteristics. While the cloud albedo enhancement (Twomey effect) of warm clouds has received significant attention, the authors discuss various other effects, including the cloud lifetime effect, semi-direct effect, and changes in the hydrological cycle. They highlight the need for better representation of these effects in global climate models and the uncertainties in current estimates. The review covers observational data, global climate model simulations, and the impact of aerosols on different types of clouds, such as water clouds, mixed-phase clouds, and ice clouds. It also discusses the aerosol-induced changes in the surface energy budget and their implications for precipitation patterns. The authors emphasize the complex interactions between aerosols and the climate system, which require further research to fully understand and model.