The underground disposal of industrial quantities of CO2 is entirely feasible. Cost is the main barrier to implementation. The preferred concept is disposal into porous and permeable reservoirs capped by a low permeability seal, ideally, but not necessarily, at depths of around 800 metres or more, where the CO2 will be in a dense phase. New concepts and refined reservoir models are continually emerging. As more regional estimates are carried out it appears that there will be ample underground storage capacity in the worlds sedimentary basins. Storage will be stable over geological timescales. The (remote) possibility of an escape of CO2 from a storage reservoir onshore merits further investigation and modelling. It would be highly desirable to learn as much as possible from the operators of the new CO2 disposal schemes arising from natural gas processing in offshore gas fields, as few such opportunities may arise.