Blasphemous? No, at least I don't think so.
Irreverent? Yes, a tad -- in the same vein as Monty Python's reading from the Book of Armaments, though I would offer my writing did have a tad more respect. Heck, I didn't even offer that the Book of Climaticus was a book of the Bible.
Consider the theme - God looks down upon liberal eastern America, and doesn't like the fact that some humans (of the liberal persasion, for the most part) have decided that people can change the climate of the Earth. God decides to teach these people a lesson through continous rains, not of the Biblical proportions of Genesis, but still a scourge upon the land, that only He is in charge of such matters. The liberals are not repentent, but God has achieved his mission because the rest of humanity now disregards their message and accepts His.
Not quite sure what is blasphemous about that.