Many methods of carbon sequestration are quite high tech. In some cases the carbon is removed as CO2 during the industrial processes that produce it, then converted to an easily transportable solid or liquid, then buried beyond reach in deep caves or under oceans in now-dry oil or gas wells. There’s a promising new idea, Kevin Bullis tells us in Wired, from scientists at the Santa Cruz campus of the University of California. It uses the interaction of seawater on limestone, in much the same way that caves are carved out by the sea in limestone.
The process proposed replicates that and accelerates it. CO2 in water makes the water slightly more acidic, and acts upon limestone to form calcium bicarbonate, the soluble salt that’s a constituent of hard water. When exhaust gases are exposed to crushed limestone, it is possible to remove 70 – 80% of a power plant’s carbon dioxide and put it into seawater as soluble calcium bicarbonate. The salt already is in seawater as a result of natural processes, and there would only be a marginal increase in its concentration even if the world’s coastal power plants all switched over to this technology. Many power plants already pump seawater for cooling, so the problem would be getting the limestone to them in sufficient quantities. This calls for a pilot power plant to test that the system does indeed out as efficiently, cheaply and safely as it promises to. Oh, and there’s a modest and unexpected bonus: the calcium bicarbonate could make the seas locally rather less acidic than they are being made by increases in atmospheric CO2.
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Madsen Pirie 
This of course assumes that carbon dioxide emissions are a problem that needs solving.
I rather think that the hyperbole emissions emanating from the IPCC et al are a much more pressing problem, given the economic impact they are having globally.
Why remove CO2 when there is no need to ? Drax Power Station at Selby in Yorkshire was the second largest coal burning power station in Europe. I stated WAS because it now burns a high proportion of Biofuel {wood pellets) and Drax is converting from coal to exclusive use of biofuel in the very near future. Renewable energy is competing with fossil fuels as a source of energy in the UK and in the next two decades it will overtake it.. Wind energy is already providing nearly 20% of our daily electrical supply and the North Sea Wind Farms are expanding almost exponentially. The next phase includes 350 giant wind generators which are invisible from the shore but will provide a substantial input into the Grid. They have a projected lifespan about the same as a conventional Power Station i.e. 25 years but their energy source is pollution free forever and their payback period is only 1.1 years compared with 2.2 years for fossil/biofuel power stations and 3.5 years for nuclear power.