Having followed proposals to store CO2 in minerals like olivine on this blog, I found this recent story about an experiment in Iceland interesting.
The basic idea was to dissolve CO2 in water (like in your soda drink can). Then pump the water under pressure underground into an environment rich in minerals that will react with the CO2 to form various rocks.
The experiment was a success. 95 percent of the CO2 was converted to rocks in less than two years.
The author of the article, Dom Wolf-Boenisch, notes as a remaining problem of the process that it costs $17 per ton of CO2, which works out to about twice of the cost of storing one ton of CO2 in supercritical state.
I am not sure that is really a problem. Turning CO2 into rocks is a permanent solution. Storing it underground requires operating a storage facility for thousands of years, and comes with leakage problems.
Anyway, $17 a ton would work out to around $600 billion to turn the 35.9 Gigatons of CO2 emitted worldwide in 2014 into rocks.
World GDP is estimated at $78 trillion in 2014, so those $600 billion are less than 1 percent of that figure.
I think that’s a bargain, compared to the damages expected from unmitigated global meltdown.
And that’s the price estimate after one preliminary study. Those prices would go down massively if this is done at scale.
Anyway, those costs only matter as long as people are not required to clean up their mess. Require by law everywhere that every gram of CO2 dumped into the atmosphere by burning fossil fuel needs to be balanced by paying for one gram of CO2 permanently removed from the atmosphere, by this or any other process. Then just let the market figure out if those $600 billion a year can be beat.