People and businesses in Wales will still want to fly and if they cannot fly from Cardiff, they will simply go elsewhere, potentially with additional carbon emissions in the process.
Bydd pobl a busnesau yng Nghymru am hedfan o hyd ac, os na allant hedfan o Gaerdydd, byddant yn mynd i rywle arall, a allai gynhyrchu allyriadau carbon ychwanegol.