I agree that carbonation does little to offset the carbon intensity required to produce new cement/concrete. Carbonation could be included in more complex GWP impact models over time, but should not be the center of the conversation. It’s more valuable to consider the full carbon story so we’re not “saving” carbon via carbonation that’s actually resulting in a lot of net emissions. I’m editing that story out of this summary because I agree that it’s misleading.
As for designing for reuse - this is a huge opportunity for precast elements, so we’ll see if that can become more standard practice. I agree with the other steps you’ve outlined as well, but I also think it’s important to acknowledge the big reductions we can implement sooner rather than later (being more conscious of cure time vs construction schedules, lower cement content, including GWP requirements in concrete specs). But to support continued reduction over time, we must implement policy mechanisms like Buy Clean. Performance-based requirements like this will provide market incentive that supports innovative technologies and changes that you’ve mentioned, and paves the way for design firms to follow suit in implementing GWP requirements.
Blue Planet is great!! I’d love to see that product get to a point where it can be scaled up.