I'd half expect that argument to be countered with the proposal that since supersonic planes will have a higher cruise altitude you could just offset the climat

I'd half expect that argument to be countered with the proposal that since supersonic planes will have a higher cruise altitude you could just offset the climate effect of the carbon dioxide by adding enough sulfur to the fuel (https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering) https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols... says Airliners could use lower-quality sulfur-rich fuels on higher altitudes. That approach would utilize regular flights and enable airlines to use cheaper fuels on long-distance flights. It would require using separate fuel tanks for takeoff and landing in populated areas, due to toxicity and olfactory sensations of sulfur oxides. This can be achieved in many airliners without difficulty, since they already have separate and selectable wing and fuselage fuel tanks.), and I am not even sure if I would be fascinated or appalled by the argument...