Scientists found a workable way of reducing CO2 levels
Adding lime to seawater increases alkalinity, boosting seawater's ability to absorb CO2 from air and reducing the tendency to release it back again.
The important point is that when you put lime into seawater it absorbs almost twice as much carbon dioxide as is produced by the breaking down of the limestone in the first place.
The Cquestrate project has a web page; here's how they describe the idea; and here's a chance of getting involved. I think this is HUGE!
They also have this awesome slideshow presentation, which goes into the gory but interesting details of all the chemical reactions.
Here is their idea of how they would do it (subject to economic feasibility):
- The Nullarbor Plain is the world's largest single piece of limestone and occupies an areas of about 200,000 km2
- With an average thickness of 50m, there is 10,000 km3 of limestone
- To sequester 1 billion tonnes of carbon (GtC) would require the excavation of 1.5 km3 of limestone
- Between 1750 and 2004 humankind has emitted 305 GtC. Current emission rates are about 7 GtC per year
- Thus employing this process on 500 km3 of limestone (about 5% of the limestone in the Nullarbor Plain) would return carbon dioxide levels to pre-industrial levels.
I hope all of this comes true. I think, economic viability of converting CaCO3 into CaO will be the biggest hurdle.