Permanent storage of carbon dioxide in geological reservoirs by mineral carbonation

Atmospheric CO2 concentration has increased from 280 ppm during pre-industrial times to 380 ppm today as a result of human input, and this is thought to be causing enhanced global warming and ocean acidification1. Between 2000 and 2005, global CO2 emissions from burning fossil fuels averaged 26.4 Gt CO2 yr−1, at or above the highest rates predicted by the Intergovernmental Panel on Climate Change (IPCC)2. Stabilization of atmospheric CO2 below 450 ppm requires a 30 to 85% net reduction in CO2 emissions by 2050 (ref. 1). Owing to the continuing use of fossil fuels, CO2 capture and storage should be a component of realistic plans to cap or reduce atmospheric CO2 concentrations3,4. Geological formations, such as deep saline aquifers, have been proposed as repositories for anthropogenic CO2 (refs 3,5,6). The long-term safety and permanence of storage will depend on physical and chemical controls within the storage reservoir. Injection of CO2 modifies ambient formation waters, inducing fluid–rock reactions that may lead to the immobilization of injected CO2 (ref. 3), or alternatively to increased permeability7. Thus, the permanence and safety of geological CO2 storage will be determined by in situ fluid–rock reactions.