The Penn and Teller DiHydrogen Monoxide hoax is a good example of a hoax than deceives with the truth. It is a play on ignorance and faith. "Believers" take the truth and let their imagination run wild. A hoax doesn't require a hoaxer or someone planning the hoax. People can deceive themselves with out any assistance at all.
What Really Happened, is a web page that has a fairly extensive list of things claimed to be caused by global warming. The beauty of a well planned hoax is to let the audience do it to themselves, like the Penn and Teller skit. Once a seed is planted, observers should be able to have a great many laughs as they watch players convince themselves and others of a relationship that continues to grow more and more unbelievable. At some point, MOST should catch on an realize the humor. Some never will though. That is the sad reality, a good joke is wasted on many.
Global warming, at least the Catastrophic end of the world version, has become a joke and we are now stuck watching the least sharp tacks in the box flail around. Not fun. A joke needs to be appreciated by as many as possible.