University of Calgary climate change scientist David Keith and his team are working to efficiently capture the greenhouse gas carbon dioxide directly from the air, using near-commercial technology.The article says that capturing a tonne of CO2 would cost just 100 kwh of electricity, meaning that the energy costs should be something like $10-15/tonne of CO2. A cap-and-trade system with a floor price of $40/tonne would work rather nicely in this case.
In research conducted at the U of C, Keith and a team of researchers showed it is possible to reduce carbon dioxide (CO2) – the main greenhouse gas that contributes to global warming – using a relatively simple machine that can capture the trace amount of CO2 present in the air at any place on the planet.
"At first thought, capturing CO2 from the air where it's at a concentration of 0.04 per cent seems absurd, when we are just starting to do cost-effective capture at power plants where CO2 produced is at a concentration of more than 10 per cent," says Keith, Canada Research Chair in Energy and Environment.
There's still the question of what to to with megatonnes of CO2. I'm definitely a sequestration skeptic, but there's multiple forms of solid carbon that could theoretically preserve the carbon underground or underwater for millenia without risk of it coming back.