Reduction in global greenhouse gas emissions is a key issue of today’s global warming, which may endanger modern human civilization. In addition to greatly expanding the use of renewable sources of energy and using energy much more efficiently, part of the solution to this challenge is CO2 capture and storage (CCS), a set of technical solutions to remove CO2 from industrial processes and to inject it into the subsurface in order to isolate the CO2 from the atmosphere for over 1000’s of years. CO2 storage or geologic carbon sequestration is a method of securing carbon dioxide in deep geologic formations to prevent its release to the atmosphere. This lecture will first addresses the important role and contribution of CO2 storage in the era of carbon reduction. Following that, subsurface environments of trapping CO2, concepts, methods and strategies of implementing CO2 storage will be introduced.