Should We Deploy Solar Geoengineering to Cool the Planet?

“We are not on track to meet 1.5°C or even 2°C. Stratospheric aerosol injection is the only technology that could meaningfully reduce temperatures within years, not decades. Responsible research is necessary to understand whether and how it might be used — ignoring it because it's uncomfortable is not a climate strategy; it's wishful thinking.”

“The research community is not proposing deployment but field trials to understand atmospheric behavior. Blocking outdoor experiments on precautionary grounds is epistemically self-defeating — we cannot know if it works, at what scale, or with what side effects without testing it. The precautionary principle cannot be applied to exclude the only rapid-response option.”

“Solar geoengineering creates classic moral hazard. Once even the prospect of a technological fix exists, political pressure to cut emissions — already weak — will collapse further. The history of carbon capture is instructive: its prospect was used for decades to defer emissions reductions that never came. We are not deciding between geoengineering and emissions reductions; we are choosing geoengineering as an excuse to continue emissions.”

“Stratospheric aerosol injection will change precipitation patterns in ways that benefit some regions and devastate others. Monsoon-dependent populations in South Asia and sub-Saharan Africa are the most likely losers, and they have no voice in the decision to proceed. Solar geoengineering requires a global governance structure that does not exist and may be impossible to build.”