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Abstract. The Middle East and North Africa (MENA) region is the dustiestregion in the world, and understanding the projected changes in the dustconcentrations in the region is crucial. Stratospheric aerosolinjection (SAI) geoengineering aims to reduce global warming by increasingthe reflection of a small amount of the incoming solar radiation to space,hence reducing the global surface temperatures. Using the output fromthe Geoengineering Large Ensemble Project (GLENS), we show areduction in the dust concentration in the MENA region under both the globalwarming (RCP8.5) and GLENS-SAI scenarios compared to the present-dayclimate. This reduction in dust over the whole MENA region is stronger underthe SAI scenario, except over dust hotspots and for the dry season. In otherwords, in the summer, with the strongest dust events, more reduction has beenprojected for the global warming scenario compared to the SAI scenario.The maximum reduction in the dust concentrations in the MENA region (underboth global warming and SAI) is due to the weakening of the dusthotspot emissions from the sources of the Middle East. Further analysis ofthe differences in the surface temperature, soil water, precipitation, leafarea index and near-surface wind speed provides some insights into theunderlying physical mechanisms that determine the changes in the future dustconcentrations in the MENA region. Detailed correlation analysis over dusthotspots indicates that lower future dust concentrations are controlled bylower wind speed and higher precipitation in these regions under boththe RCP8.5 and SAI scenarios.