Direct aerosol radiative forcing (DARF) remains a leading contributor to climate prediction uncertainty. To monitor the spatially and temporally varying global atmospheric aerosol load, satellite remote sensing is required. Despite major advances in observing aerosol amount, type, and distribution from space, satellite data alone cannot provide enough quantitative detail, especially about aerosol microphysical properties, to effect the required improvement in estimates of DARF and the anthropogenic component of DARF. However, the combination of space-based and targeted suborbital measurements, when used to constrain climate models, represents an achievable next step likely to provide the needed advancement.