Coal, oil, and natural gas currently supply about 85% of the world's energy needs. Unfortunately, the burning of these fossil fuels is the major source of anthropogenic carbon dioxide, which is also the main greenhouse gas released to the atmosphere. One promising means by which to reduce CO₂ emissions, and so the atmospheric buildup of CO₂, is geosequestration. Geosequestration, also known as carbon capture and storage (CCS), involves the long-term storage of CO₂ in deep subsurface geological reservoirs. Geosequestration comprises several steps that include the capture of CO₂, the transport of CO₂, the injection of CO₂ into suitable reservoirs, and finally, the storage and monitoring of the CO₂ that has been introduced into the reservoir.

Geological input into the evaluation of storage sites, including injection, storage, and monitoring and verification of volumes and movement of CO₂ plumes, is critical for acceptance of CCS technologies. Detailed characterization and realistic modeling of reservoir and seal properties, as well as of rock and fault integrity, will permit a more viable analysis of risks associated with the subsurface containment of injected CO₂. Geosequestration can be a significant factor in the portfolio of CO₂ emissions reduction strategies because by reducing CO₂ emissions while still allowing for the continued use of fossil fuels, geosequestration buys time for the transition to renewable energy sources.