> I think that all of the companies that set these public carbon emissions goals as PR should be held fully accountable for missing them.

Then they simply wouldn't set any such goals. Why would they bother risking it?

If you want targets that are accountable, advocate for actual laws that set emissions limits, and a government that is willing to enforce them. Nobody is going to eat a fine on a completely voluntary PR statement. It's easier to just not make the statement in the first place.