What folks seem to forget about the intial interest in 'carbon credits' and with it the whole process of having a 'carbon exchange' was to expose the COSTS of polluting, and with it the hope that this would provide the more obvious body of data to the major 'single source' producers. That way was engaged in trying to use the various obvious economic tools that come with market exchange systems.
The good natured bash on that helps folks look at what has come of the process.
The good news remains, that while our species may not survive the transition, there is nothing to say that the next evolutionary filler of the vacuum will do better...