A method of capturing carbon dioxide so that it is not released into the atmosphere. This is a proposed response to the increase of CO₂ in the atmosphere---mostly from anthropogenic sources since the industrial revolution. It can be achieved chemically in two obvious ways: carbon dioxide can be captured after a fossil fuel has been combusted in either the concentrated exhaust stream or, for example, carbon dioxide can be generated in fuel consumption/precombustion in the so-called syngas (synthesis gas) process which produces molecular hydrogen and CO from a methane-rich feed gas. That mix reacts with high temperature steam to produce H₂ and CO₂ which is captured. H₂ is burned to produce energy. Even more difficult is collecting CO₂ from the atmosphere at ambient concentrations in tropospheric air. Carbon dioxide produced by hydrocarbon combustion can be pressurized and injected into old salt mines or used in enhanced oil recovery.