Carbon credits are an even more brilliant scam than fake driveway repairs and Ponzi schemes in the securities market. With the other two scams people actually buy something that's advertised to be of definite, measurable value to them. The scammer has to be always able to run out of town when he inevitably gets caught and the scamees go after him because they didn't get what they bargained for.
The carbon credit scammer, OTOH, is selling a fake "moral value" to the scamees, who have no reason even to ask if they've received their money's worth and no way to measure the value even if they ask. Hence, carbon credit scams aren't even self-limiting like ordinary scams. A grifter's paradise is in the making.
So, could we say that the "moral value" is the equivalent of a self-assessed "guilt tax" based on whatever the individual feels their guilt is worth?