Action on CFCs and ozone depletion was a lot easier with a lot less economic/industrial impact. Work on CO2 emissions is much more difficult and much more costly. It also is more of a direct challenge to the implicit value assumptions of a huge group of people (that humans have "dominion" over the Earth, and it is theirs to subject rather than theirs to responsibly steward). It's an instance of the "boomerang effect" writ large.