As a polluter, the Indy 500 is so much more than a few hours of muscle machinery going around a circle in what passes for sport: it's 2-plus weeks of practice races, countless generator-powered preliminary events and media trucks -- seas of RV camping -- huge corporate sponsorships, etc, glorifying... I have no clue as to its appeal, short of primal, testosterone-fueled thirsts for blood and spectacle.
Is it possible, then, to calculate the sum of carbon emissions related to this sport? Can honest numbers legitimately be ascribed? I don't know. But whatever the estimate, multiply it by the Daytona 500, the entire NASCAR schedule, and all such sport of its kind.
Happy Memorial Day.