Startup creates Lego-like brick that can store air pollution for centuries

Yes but it's wood that you are not allowed to burn or let rot, or the CO₂ gets released again. Basically, cut down trees and store them in oxygen-free water, salt mines, deserts or permafrost areas (or peat bogs, as nature did it over millions of years) where no bacteria/insects will feed on the wood and no humans come to scalp it. There is no way this can be economical, even with today's carbon credits. Trees are "free" solar carbon capture devices but slow and inefficient, and need to be logged-and-stored continuously to work at all, as there is only a very limited space that we can cover in new forests in the next few decades.

I know they just want to find the best use for waste wood but I think there is too little of it in the first place.