Disposal of pollutants from chimney scrubbers

Technologies now exist for the removal of carbon and carbon dioxide, sulphur dioxide and particulate material from the gaseous emissions of combusted carbon-based fuels, applicable, for example, at power stations. Widespread adoption of flue gas "scrubbing" raises the problem of what to do with the waste products.

Sulphur removed from coal and oil-fired chimneys can be sold, as to a limited extent can flue ash. However, current carbon emissions dwarf any human experience in handling masses of material. Annual world steel production, for example, was about 700 million tons; carbon dioxide emissions from energy are 22 billion tons. Reinjection of carbon dioxide into depleted natural gas or oil fields would quickly fill the available reserves. Proposals to inject carbon dioxide into the deep ocean, which has enormous buffering capacity, carries unknown environmental effects.