Absorbing CO2 with a resin

 Research into a resin for passive absorption of atmospheric CO2.  

Bloomberg: What about all the carbon we've already poured into the atmosphere? If only there were a device that could take some of it back out. Researchers at Arizona State University’s Center for Negative Carbon Emissions are working on one. They discovered a commercially available resin that can grab carbon dioxide at low concentrations when the material is dry and release it when the material is moist. The CO2 it collects could be stored underground, used in greenhouses, or fed to algae for biofuel production.

But this is also a passive component of energy producing algae farms, it can deliver high concentrations of CO2 to algae farmed under sanitary conditions.  The  capital costs of algae energy drop, possibly by an order of magnitude. Instead of distributing the algae out tp the sun over large acres, we re-focus the sun to a central algae manufacturing cell where CO2 concentrated resin is the fast acting fuel.  We get dense, rapid algae growth

This is the correct direction, or at least a sufficient direction for planning purposes.   We can begin to calculate the time scale over which technology will be available for global CO2 management.  Which then begs the question, what is stable CO2, because the ice core says we need to drop a couple of degrees.