For years, scientists and others concerned about climate change have been talking about the need for carbon capture and sequestration.

That is the term for removing carbon dioxide from, say, a coal-burning power plant’s smokestack and pumping it deep underground to keep it out of the atmosphere, where it would otherwise contribute to global warming.

C.C.S., as the process is known, has had a spotty record so far. While there are some projects being designed or under construction, only one power plant, in Canada, currently captures and stores carbon on a commercial scale (and it has been having problems). Keeping a lot of CO 2 out of the atmosphere would require a costly expansion of the technology to many more power plants and other industrial facilities.

Among the concerns about sequestration is that carbon dioxide in gaseous or liquid form that is pumped underground might escape back to the atmosphere. So storage sites would have to be monitored, potentially for decades or centuries.