Please provide a source and background. Average American or average person on Earth and do you mean annual or lifetime carbon footprint. You talking about a Falcon launch or a Super Heavy Launch or an SLS launch. Are you talking total lifetime carbon footprint divided by number of launches or are you just talking the engine emission for a single launch. The "real" carbon footprint should include the factory, transportation, launch infrastructure, raw materials, propellants, consumables for testing including engine test firings, engine test stand infrastructure,.....

TEK