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The infrared method enables the monitoring of desert aerosol plumes over the African continent, using satellite observations acquired at midday. The method is based on the strong dust forcing in the thermal IR, involving the additive effects of surface radiative cooling and of extinction of the upward IR radiance through the dust layer. Remote sensing of dust plumes is achieved using an algorithm that processes the Meteosat-IR imagery. As a result, daily images of Infrared Difference Dust Index (IDDI) values are obtained. The algorithm is outlined and the product is described below. The method is applied to a series of images covering the period 1984-1998. The resulting dataset constitutes the basis of a 15-year climatology of Saharan, Sahelian, Somalian, Arabian and southern African dust events. Such a climatology consists of monthly means of IDDI values computed for 30'X30' pixels. The dust distribution obeys a marked annual cycle alternating between turbid and comparatively clear periods. The sources of emission, identified as areas of maximum IDDI values, show specific seasonal cycles of activity. The year-to-year variability is described.