Good catch, Haiku Guy!
Sources vary on the quantity, but your observation is no doubt roughly correct.
There was a case a few years back in San Francisco, where about a dozen bicyclists were harassing a family of four in a minivan because they minivan was despoiling the planet by emitting climate destroying CO2.
It was pretty clear, by a cursory analysis, that the 12 bicyclists were emitting more excess CO2 by chasing the minivan down the street than the minivan was by driving along.