I don’t think it’s clear at all that concrete wouldn’t work for a moon base. I can definitely at least imagine that there might be some CO2-scrubbing technology

I don’t think it’s clear at all that concrete wouldn’t work for a moon base. I can definitely at least imagine that there might be some CO2-scrubbing technology that might be practical on the scale of a moon base that wouldn’t be if scaled up to the entire planet Earth.