The invention teaches a practical method of recovering CO.sub.2 from a mixture of gases, and sequestering the captured CO.sub.2 from the atmosphere for geologic time as calcium carbonate and provides a CO.sub.2 scrubber for carbon capture and sequestration. CO.sub.2 from the production of calcium oxide is geologically sequestered. A calcium hydroxide solution is produced from the environmentally responsibly-produced calcium oxide. The CO.sub.2 scrubber incorporates an aqueous froth to maximize liquid-to-gas surface area and time-of-contact between gaseous CO.sub.2 and the calcium hydroxide solution. The CO.sub.2 scrubber decreases the temperature of the liquid and the mixed gases, increases ambient pressure on the bubbles and vapor pressure inside the bubbles, diffuses the gas through intercellular walls from relative smaller bubbles with relative high vapor pressure into relative larger bubbles with relative low vapor pressure, and decreases the mean-free-paths of the CO.sub.2 molecules inside the bubbles, in order to increase solubility of CO.sub.2 and the rate of dissolution of gaseous CO.sub.2 from a mixture of gases into the calcium hydroxide solution. The CO.sub.2 scrubber recovers gaseous CO.sub.2 directly from the atmosphere, from post-combustion flue gas, or from industrial processes that release CO.sub.2 as a result of process. CO.sub.2 reacts with calcium ions and hydroxide ions in solution forming insoluble calcium carbonate precipitates. The calcium carbonate precipitates are separated from solution, and sold to recover at least a portion of the cost of CCS.