A method for the capture of CO 2 in a composition, the release of said CO 2 from said composition, and the subsequent regeneration of said composition for re-use, said method comprising performing step a): (a) capturing the CO 2 by contacting at least one gas with a capture composition comprising at least one metal salt of a carboxylic acid, at least one water-miscible non-aqueous solvent and a protic solvent selected from water and an alcoholic solvent; wherein said at least one metal salt of a carboxylic acid is initially present in said composition at a level of between 1M and 14M; wherein said water miscible non-aqueous solvent is selected from dimethylsulphoxide (DMSO), N-methylpyrrolidinone, dimethylformamide, tetrahydrofuran, 2-methyltetrahydrofuran, acetonitrile, sulfolane, 1,1,3,3-tetramethylurea, N,N'-dimethyl-N,N'-trimethyleneurea (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone (DMPU)), 1,3-dimethyl-2-imidazolidinone, 1,4-dioxane, 1,3-dioxolane, lactate esters, polyethers, acetone, anisole, benzonitrile, benzyl alcohol, 1-butanol, 2-butanol, tert-butanol, 2-butoxyethanol, 2-butoxyethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, tert-butyl acetoacetate, carbon disulphide, cyclohexanone, diethoxy ethane, 1,2-dimethoxyethane, N,N-dimethylacetamide, ethanol, 2-ethoxyethanol, ethyl formate, ethylene glycol, ethylene glycol diethyl ether, 2-ethyl-1-hexanol, formamide, glycerol, 1-heptanol, 2-heptanone, 1-hexanol, 2-hexanol, 2-methoxyethanol, 2-methoxyethyl acetate, 1-methoxy-2-propanol, 3-methyl-1-butanol, methyl butyl ketone, methyl isobutyl ketone, methyl ethyl ketone, methyl formate, 5-methyl-2-hexanone, 4-methyl-2-pentanol, 2-methyl-1-propanol, nitrobenzene, nitromethane, 1-octanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-pentanone, 3-pentanone, 1-propanol, 2-propanol, propionaldehyde, 2-propoxyethanol, tetralin, triethyl orthoformate and 3,5,5- trimethyl-1-hexanol; and then performing, in order, steps b) and c): (b) releasing said CO 2 by adding at least one protic solvent selected from water and an alcoholic solvent; and (c) regenerating the capture composition by partial or complete removal of said added protic solvent from said composition (a) capturing the CO 2 by contacting at least one gas with a capture composition comprising at least one metal salt of a carboxylic acid, at least one water-miscible non-aqueous solvent and a protic solvent selected from water and an alcoholic solvent; wherein said at least one metal salt of a carboxylic acid is initially present in said composition at a level of between 1M and 14M; wherein said water miscible non-aqueous solvent is selected from dimethylsulphoxide (DMSO), N-methylpyrrolidinone, dimethylformamide, tetrahydrofuran, 2-methyltetrahydrofuran, acetonitrile, sulfolane, 1,1,3,3-tetramethylurea, N,N'-dimethyl-N,N'-trimethyleneurea (1,3-dimethyl-3,4,5,6-tetrahydro-2-pyrimidinone (DMPU)), 1,3-dimethyl-2-imidazolidinone, 1,4-dioxane, 1,3-dioxolane, lactate esters, polyethers, acetone, anisole, benzonitrile, benzyl alcohol, 1-butanol, 2-butanol, tert-butanol, 2-butoxyethanol, 2-butoxyethyl acetate, 2-(2-butoxyethoxy)ethyl acetate, tert-butyl acetoacetate, carbon disulphide, cyclohexanone, diethoxy ethane, 1,2-dimethoxyethane, N,N-dimethylacetamide, ethanol, 2-ethoxyethanol, ethyl formate, ethylene glycol, ethylene glycol diethyl ether, 2-ethyl-1-hexanol, formamide, glycerol, 1-heptanol, 2-heptanone, 1-hexanol, 2-hexanol, 2-methoxyethanol, 2-methoxyethyl acetate, 1-methoxy-2-propanol, 3-methyl-1-butanol, methyl butyl ketone, methyl isobutyl ketone, methyl ethyl ketone, methyl formate, 5-methyl-2-hexanone, 4-methyl-2-pentanol, 2-methyl-1-propanol, nitrobenzene, nitromethane, 1-octanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-pentanone, 3-pentanone, 1-propanol, 2-propanol, propionaldehyde, 2-propoxyethanol, tetralin, triethyl orthoformate and 3,5,5- trimethyl-1-hexanol; (b) releasing said CO 2 by adding at least one protic solvent selected from water and an alcoholic solvent; and (c) regenerating the capture composition by partial or complete removal of said added protic solvent from said composition