ACC is the new denomination of the old church of GW, a political convention of the left which used to be the holy church of GC, which trial balloon popped after a few years of justifiable ridicule during which time GW (now ACC) deacon poliscientists were called out by their legislative apostles to fabricate sufficient hokum for prophetic purposes to warrant a drop, albeit temporary, in ridicule long enough to evangelize large numbers of eager proselytes with their message of bad news. Not satisfied with those numbers, the apostles expanded their mission field to the ripe fields of Hollywood, discipling numerous converts among those more talented than they in the art of make believe which greatly expanded the bad news worldwide, particularly among the naive and well-to-do. The coffers of the church greatly expanded and buldged in tithes and deacon poliscientists eventually rose to the level of full-fledged shamans - while at the same time enemies of the gospel of bad news gathered their forces and waged war against the recently-patched and reinflated new trial balloon the GC faithful now called CC. To counter the rising forces against them, the [new] CC-ites adopted an early measure of the GW era to demonize the unfaithful by prepending their own name with an "A" - anthropo-something-or-other, which the policientists prophesied falsely would sway the unfaithful by targeting their emotions, being human themselves. "Anthropogenic" - that's the word - loosely meaning "humans are to blame."
It's truly a history of change and adaptation as various convolutions emerged to address a righteously skeptical world. When the "GC" (global cooling) name didn't fly for their religion, they tried "GW" (global warming). That garnered more support - mostly because they retained the "G" (global) to make their message universal, but they added the "A" as noted above to counter enemy ridicule deeping the guilt of their own membership, strengthening their power over them. When neither "C" (cooling) nor "W" (warming) resulted in the desired effect, church leaders opted for a change and went with "CC" - the first "C" referring to "Climate" (not to be confused with "Weather") and the second "C" referring to "Change" (not to be confused with reason and common sense). With the human blame factor prepended, you have the current manifestation and TLA of the church's faith - "ACC."
Interestingly, a new clergy class is emerging within the church - the APS, or "astro-poli-scientist" who are on the verge of breaking new ground with the church's gospel of bad news. Their claim (the prophetic truths are in the works right now), will be that the earth, changing as it is and floating in the solar system as it is, is having a deleterious effect on the climates of neighboring planets - most notably Mars - where the thus far unsuccesful search for ice (solid water to the uninitiated) may be directly linked to the existence of SUVs in America. The research is ongoing (new funding just approved with the Health Care Reform bill), but they are expecting a breakthrough any day now, my sources tell me.