You seem to be interested in global warming so you might want to look at the article I just started on the term CAGW. I had noticed it on some blogs but don't really know enough about the topic to flesh the article out. Thanks.
You know as much about it as I do. I don't know where it originated, but it was probably somewhere in the denialist blogosphere (deniosphere?). I've never seen it used in any academic or reputable publications. If I had to guess, I'd say it was originally concocted by lukewarmers to make themselves out to be the "sensible moderates" of the climate change "debate."