Aerosolized Calcium Hydroxide for Climate Mitigation:Conceptual Feasibility and Governance Challenges

Abstract Atmospheric carbon dioxide (CO₂) concentrations are on the rise, increasing global warming and environmental risks. To protect our environment, carbon dioxide removal (CDR) technologies are increasingly recognized as essential instruments to rapid de-carbonization. This paper explores the conceptual possibility of aerosolized calcium hydroxide [Ca(OH)₂] dispersal as a CO₂ removal technique. The underlying chemistry is simple: CO₂ reacts with Ca(OH)₂ to form stable calcium carbonate (CaCO₃). Stoichiometric calculations shows that 1\,kg of Ca(OH)₂ can bind 0.594\,kg of CO₂, so removing 1\,Gt CO₂ would require approximately 1.7\,Gt of Ca(OH)₂. The materials required are comparable to global cement production, so scaling, while challenging, is not impossible. This paper assess key factors influencing feasibility, including atmospheric residence times, life cycle carbon balance, ecological deposition impacts, and governance challenges. While carbonation offers a permanent sink, achieving net-negative outcomes depends on decarbonized Ca(OH)₂ production and management of side effects, particularly in soil and marine ecosystems is necessary. Even partial deployment at a gigatonne scale represents a meaningful contribution, comparable to the annual emissions of a major industrialized nation. This paper positions aerosolized Ca(OH)₂ not as a deployable solution, but as a research direction which requires systematic study, testing, and integration into broader environmental management and CDR strategies.