First off, you, finite: this is the definition of dog-piling. There is obviously an emotional reaction people are having to this headline and people are trying to find a way to take fault in it.
The headline as reads perfectly fine and if it weren't for peoples clearly reactionary response, this wouldn't even be a thread.
Reporting something like emissions in a count of vehicles is a perfectly reasonable way to do so, at least something people can their heads around. Elsewhere in the thread people have made it about the number, or that we shouldn't care because oil tankers, or the phrasing of the headline. But none of that takes away from the point the headline makes, which is immediately understandable.
Again, I don't understand your issue with the headline and why it offends so. A car is probably the most relevant thing a person who isn't in the specific sciences of carbon estimation would have. If not cars what should they have done it in?
I think finite criticism is pretty emotional and reactionary: they don't like the conclusion so they take issue with the phrasing. And you, are here, as part of the dog pile, pushing back on that.