What many have no clue about is how coal burning is one of the biggest problems not to mention steel production, plastics, trash burning and many other pollutants that contribute FAR MORE to the "Inconvenient Man-Bear-Pig Truth" than cars do.
That's why I just laugh at self righteous nitwits-- they don't understand what they believe in. Just tell the Prius guy that he's too stupid to really know what he's talking about and that he should go straight home and turn off his air conditioner, his heat, his television, and then not go anywhere for anything other than work.