Battery technology has made huge advances in the last 20 years, and will make much more in the next 20. Battery powered drones are getting bigger and bigger. And clean electricity is getting cheaper each year, so unless the tendency is reversed, it will be dirt cheap sooner or later. Anyway, one of the main strategies for zero CO2 is replacing planes with trains as much as possible; most of flights can be avoided that way.
Yes, solving the concrete emissions may take a long time, but certainly not forever.
Recycling can minimize mining, processes can get better, and if emitting methane in the process end up being unavoidable, well, mines seem good places for carbon capture to me.
The carbon we exhale, well, never was the problem, and it never will be, as long we stop destroying forests.
My point is sequestration should be a cleaning strategy (in order to reduce the CO2 already in the atmosphere), and not a compensating strategy to avoid cutting emissions (because then the cleaning is going to take forever, or, more likely, never happen).
