[unsung]

> David Friedberg argued on the all in podcast that a 25 square-mile areal of these would be enough to capture all CO2 currently in the atmosphere.

I felt like napkin mathing it, and even a cursory check completely obliterates that claim. Adding 1 ppm (volumetrically) of CO2 to the atmosphere is about 2 Gt of CO2, and we're at about 400 ppm. Carbon is 27% by mass. Monocrystalline diamond is 3.5 g/cm3. This makes a prism with the specified base 1km high. Talk about a ring.

The linked article seems to indicate that the researchers are also much more conservative with their claims than Freidberg, and state their technology is about 8x more efficient at capture than corn. Very cool, but nowhere near that sort of magnitude, as 8x that area would be only a fraction of the farmland in the continental US alone (by a factor of 1000).

* Edited for math