Of course, China is a very big country with an industry that is growing at a rapid rate. So they have to add even more coal to keep up with demand.
But it is wrong to think that they are not doing anything.
As for carbon capture. People have been talking about that for a long time. Today it seems that the most effective way of carbon capture is to plant some trees.
Personally, I think it is great that banning sale of ICE vehicles are already on the table.
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
The upside is, that once we accept that this is not happening we can move on from these attempts and fully focus on technologies that capture/remove carbon from the air. This one to efficiently convert CO2 into starch (https://newatlas.com/science/artificial-synthesis-starch-fro...) comes to mind. I have no insight of my own to contribute, but 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. (again, just quoting, not able to verify this myself)