The role of aerosols in the climate system: Results of numerical experiments in climate models

Three principal questions are recurrent with the consideration of an aerosol related climatic effect: (1) do aerosols heat or cool the atmosphere, (2) are aerosol climatic effects significant and (3) can numerical models be validated by predicting a climatic change associated with a measured aerosol-event. Each of these questions will be addressed from a historical perspective. In addition, the most recent aerosol-related modeling will be discussed as well as recommendations for future research.