"Several researchers investigating chemical systems for capturing CO2 from the air have suggested that air capture could be a viable climate mitigation technology costing no more than a few hundred dollars per tonne of CO2 avoided," begins the study. "It has been further argued that air capture may be cost-competitive with more accepted climate change mitigation options like renewable power, nuclear power, and CO2 capture and storage from large stationary sources (carbon capture and storage, CCS)." CCS would stream concentrated carbon dioxide from smokestacks deep underground into inert geological layers capped by impermeable rock.
In 2009, US Presidential Science Advisor, John Holdren, and Energy Secretary Steven Chu, for example, proposed, " capturing carbon dioxide (CO2) directly from the air as an option that may be needed for stabilizing global CO2 concentrations and, thereby, global temperatures," notes the study.
After all, engineers have pulled carbon dioxide from the air to allow for chemical production of gases from the air since the 1930's. Both absorbent and more traditional "scrubber" technologies exist to pull off the trick.
Carbon dioxide can be pulled from the air, concludes the study, but concentrating it into a stream needed to store the stuff for thousands of years looks tough. Overall, given trends in costs to remove carbon dioxide and physics, the technology looks to break even in terms of cost only when atmospheric carbon is worth $1000 a metric ton (its value is now roughly zero in much of the world.) . . .
Any day now it will be economically viable to pay to sequestrate carbon, right? Hardly. Does anyone really believe that the harm from carbon in the atmosphere is $1,000 per ton? Note that even liberal William Nordhaus says that the optimal carbon tax is $7.40 per ton. Some others say that it is $10 to $20. This article from USA Today is interesting: