Dust emissions related to anthropogenic activities (i.e., anthropogenic dust (AD)) is not represented in most global climate models and its radiative impact remains unassessed. In this study, we develop a new and physically based method to parameterize AD emission based on the DOE’s Energy Exascale Earth System Model version 1 (E3SMv1). This method relates AD emission to the crop land use fraction in the E3SMv1 land component. Major AD sources simulated by our parameterization include those over Central America, the Sahel, North India, and North China. The annual averaged AD emission is 567 Tg yr-1 in present-day (year 2000), which contributes to 13.3 % of total dust emission. Model evaluation against satellite and ground-based observations shows that the new parameterization can represent AD emissions and global dust cycle reasonably well. We find that the total dust emission increases by 13 % (495 Tg yr-1) from 1850 to 2000 mainly due to the cropland land use fraction changes, which induces a net dust direct effective radiative forcing of -0.041 W m-2 at top of the atmosphere. This AD-induced cooling exceeds 10% of the total anthropogenic aerosol direct effective radiative forcing from 1750 to 2014 estimated by the Intergovernmental Panel on Climate Change Sixth Assessment Report. Our findings indicate an important role of AD in the regional and global climate changes, which should be included in future climate change assessments.

The source of dust in the global atmosphere is an important factor to better understand the role of dust aerosols in the climate system. However, it is a difficult task to attribute the airborne dust over the remote land and ocean regions to their origins since dust from various sources are mixed during long-range transport. Recently, a multi-model experiment, namely the AeroCom-III Dust Source Attribution (DUSA), has been conducted to estimate the relative contribution of dust in various locations from different sources with tagged simulations from 7 participating global models. The BASE run and a series of runs with 9 tagged regions were made to estimate the contribution of dust emitted in East- and West-Africa, Middle East, Central- and East-Asia, North America, the Southern Hemisphere, and the prominent dust hot spots of the Bodele and Taklimakan Deserts. Using the multi-model simulations, the present study has found common features among models on large scales, however models show large diversity in dust source attribution. The multi-model analysis estimates that North Africa contributes 60 % of global atmospheric dust loading, followed by Middle East and Central Asia sources (24 %). Southern hemispheric sources account for 10 % of global dust loading, however it contributes more than 70 % of dust over the Southern Hemisphere. The study provides quantitative estimates of the impact of dust emitted from different source regions on the globe and various receptor regions including remote land, ocean, and the polar regions synthesized from the 7 models.