The globe is mostly water. Ocean fertilization make a lot more sense than this for a whole bunch of reasons. The inter-continental sea floor automatically freezes all carbon that goes down there most of it is stored as methane. Just need a fleet of nuclear powered fertilizer ships to kick it off hopefully you get more fish as a result. https://en.m.wikipedia.org/wiki/Ocean_fertilization
The delivery of material to the center of Ocean vertices is essentially free. Any floating body winds up there eventually
I wrote about it here: https://noverloop.substack.com/p/how-to-leverage-the-plastic...