The AEROCOM-project is an open international initiative of scientists interested in the advancement of the understanding of the global aerosol and its impact on climate. A large number of observations (including MODIS, POLDER, MISR, AVHHR, SEAWIFS, TOMS, AERONET, surface concentrations and other observations of relevance) and results from more than 20 global models have been assembled to document and compare state of the art modeling of the global aerosol. A common protocol has been established and models are asked to participate in the AEROCOM experiments. Results are documented via interactive websites which give access to 2D fields and standard comparisons to observations. Regular workshops are held to discuss findings, joint publications and future directions.