Aerosol Warming Over Bright Surfaces - Kapoor

@geoengineering1 interviews Taveen Kapoor about his study [preprint] showing that purely scattering stratospheric aerosols can produce positive shortwave radiative forcing, and localized warming, over high-albedo surfaces such as snow, ice, and deserts. They discuss how diffuse light reflected from bright surfaces travels farther through the aerosol layer, increasing the likelihood of backscattering toward the surface.They also discuss why multi-angle radiative-transfer calculations reveal stronger positive forcing than the standard two-stream approximation, particularly in tropical and extratropical regions, while daily averages can obscure intense daytime forcing peaks.The conversation explores implications for SAI, including potential effects on snowmelt and regions such as the Tibetan Plateau and Sahel, as well as the growing burden of alumina aerosols from spacecraft reentry. They also discuss uncertainties and related research on alumina-based stratospheric aerosols.Paper Discussed: Zhang, L., Kapoor, T. S., Upadhyay, P., & Chakrabarty, R. K. (2026). Purely light-scattering aerosols could induce positive shortwave radiative forcing over high-albedo surfaces. EGUsphere, 2026, 1-17. https://doi.org/10.5194/egusphere-2026-3947