Carbon capture and storage (CCS), alternatively referred to as carbon capture and sequestration, is a means of mitigating the contribution of fossil fuel emissions to global warming. The process is based on capturing carbon dioxide (CO2) from large point sources, such as fossil fuel power plants, and storing it in such a way that it does not enter the atmosphere. It can also be used to describe the scrubbing of CO2 from ambient air as a geoengineering technique. Although CO2 has been injected into geological formations for various purposes, the long term storage of CO2 is a relatively new concept. The first commercial example was Weyburn in 2000.