Read here. As politicians worldwide have become possessed by CO2-mania, proposed solutions to solve the "problem" are often worse than the problem, or in the case of sequestration, it does not work as advertised:
"One key aspect of CO2 storage that has been largely ignored to date, we are told, is the issue of injection rate into the subsurface. A typical 1GW coal-fired power plant produces 20,000 tons of CO2 per day, which must be injected into an aquifer at this daily rate for decades....In two ongoing CO2 storage demonstration projects, we also learn, it has proved impossible to inject CO2 at the predicted rate without exceeding the fracture pressure of the aquifer formation. Conversely, each injection well costs millions of dollars and has an environmental impact on the surface so it is not acceptable to drill too many wells....Further problems arise in salt water aquifers where there is competition between salt precipitation and carbonate dissolution. Precisely what happens over the long term is not known. But there are some fears that, as volume of CO2 injected increases, injecting even more could get harder (and more expensive) rather than easier. It could even be the case that the energy required to pump the CO2 exceeds that of the power station producing it."