A method for producing oxygen and absorbing carbon dioxide in a single operation using a solution that contains an oxygen source and a redox partner that can react to form oxygen and a chemical species that can form an insoluble carbonate to precipitate and chemically store carbon dioxide. Carbon dioxide is introduced into the solution and the carbonate precipitates as the oxygen is generated. In particular, the invention uses an aqueous solution of permanganate and hydrogen peroxide that react in the presence of a catalyst to produce oxygen and manganese (II) ions. Carbon dioxide gas introduced into the solution reacts with the manganese (II) ions to precipitate manganese carbonate. Other cations capable of reacting with carbon dioxide to form an insoluble carbonate, for example calcium, barium and magnesium, may also be added to the solution to precipitate carbonate salts. Calcium permanganate may used as a source of both calcium and permanganate.