Carbon sequestration is the process of removing carbon from the atmosphere and depositing it in underground geologic formations / reservoirs. Carbon sequestration describes long-term storage of carbon dioxide or other forms of carbon to either mitigate or defer global warming and avoid dangerous climate change. It has been proposed as a way to slow the atmospheric and marine accumulation of greenhouse gases, which are released by burning fossil fuels.

Carbon dioxide is naturally captured from the atmosphere through biological, chemical or physical processes. Several artificial sequestration techniques have also been developed.

Storage of the CO2 is envisaged either in deep geological formations, in Deep Ocean masses, or in the form of mineral carbonates. Deep ocean storage risks greatly increasing the problem of ocean acidification.