In the past, different branches of the atmospheric sciences separately conducted research concerning the role of the atmospheric aerosol in cloud physics, atmospheric chemistry and radiative transfer. Findings of the last few years have emphasised the importance of the atmospheric aerosol for both climate change and the cycles of atmospheric trace substances In this peer- reviewed editorial, arguments are given for research needed in order to include the atmospheric aerosol as a prognostic variable in global models of climate and trace substances. A program for the necessary integrated, interdisciplinary aerosol research is formulated, combining in-situ physical and chemical aerosol characterisation, remote sensing and modelling. It is necessary to emphasise the need for integration of the key activities, which individually, by themselves, cannot yield an adequate basis for a full characterisation of the climate effect of aerosols or of changes in atmospheric composition.