Adeyemi A Adebiyi , Yue Huang, Bjørn H. Samset, Jasper F Kok 

Desert dust accounts for a large fraction of shortwave radiation absorbed by aerosols, which adds to the climate warming produced by greenhouse gases. However, it remains uncertain exactly how much shortwave radiation dust absorbs. We leverage in-situ measurements of dust single-scattering albedo to constrain absorption at mid-visible wavelength by North African dust, which accounts for approximately half of the world's dust. We find that models overestimate North African dust absorption aerosol optical depth (AAOD) by up to a factor of two. This occurs primarily because models overestimate the dust imaginary refractive index, the effect of which is partially masked by an underestimation of large dust particles. Additionally, similar factors contribute to an overestimation of AAOD retrieved by the ground-based Aerosol Robotic Network over North Africa. We conclude that the overestimation of simulated and retrieved dust absorption suggests substantial biases in current estimates of dust impacts on the Earth system, including a warm bias in dust radiative effects.