IMO, that would depend on the form the waste carbon is produced in, which would influence how it is disposed of. Taking a common hydrocarbon such as propane, an

IMO, that would depend on the form the waste carbon is produced in, which would influence how it is disposed of. Taking a common hydrocarbon such as propane, and stripping all the hydrogens out of it will produce pure carbon. Last I checked, carbon tends to be a solid at standard pressure and temperature. AFAICT, the concern about carbon pollution is it ending up in the atmosphere in the form of gaseous compounds and messing with the complex feedback loops that regulate the climate. Solid carbon isn't going to do that very well.