Geophys. Res. Lett. (2023) 10.1029/2023GL105889 "Risky known unknowns." I gotta say, this title seems self-contradictory. [But this is only the title of the concise review, the title of the actual research letter is Chemical Impact of Stratospheric Alumina particle Injection for Solar Radiation Modification and Related Uncertainties]. What the review gets right is that a wide array of potential geoengineering proposals are under discussion. But the log of unintended consequences is an even longer list. "Vattioni et al. investigated how stratospheric injections of alumina particles might perturb atmospheric composition, finding that the effects on heterogeneous chemistry could result in the destruction of more than twice as much stratospheric ozone as that eroded by chlorofluorocarbons in the late 1990s." Clearly the only silver bullet for curbing global warming depends overwhelmingly on curbing emissions of heat-trapping carbon dioxide, methane + nitrous oxide. So—CO2, CH4 + N2O. Only about 11% of the problem stems from unsustainable land clearance issues. So, absolutely no good rationale for putting the particles in the photo up high in our shared atmosphere. Period.
