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This work uses an aerosol–climate coupled system to study the direct climatic effects of dust aerosol on global arid (including hyper-arid) and semi-arid regions.Results show that dust aerosol can cause surface cooling over these regions.The cooling effects of dust aerosol are larger in the Northern Hemisphere (NH) than the Southern Hemisphere (SH).This asymmetric cooling forces a thermal meridional circulation between 30°S and 30°N,with air descending (ascending) in the NH (SH),leading to a decrease (increase) in precipitation over the arid and semi-arid regions over the NH (SH).Dust aerosol can decrease the potential evapotranspiration in arid and semi-arid regions mainly by decreasing the net radiation flux at the top of the atmosphere,which compensates for the decrease in precipitation caused by dust aerosol.Therefore,as the dominant aerosol in the arid and semi-arid regions,dust aerosol does not exacerbate the aridity over most of these regions.The effects of dust aerosol are indiscernible in the expansion of arid and semi-arid areas on a global scale.