Perhaps the apex in the global warming debate was when Al Gore used a scissor lift to take his pointer to the top of the “Hockey Stick” graph in his movie, and the IPCC featured the same hockey stick on the cover of their Third Assessment report.
After that it has tended to be downhill for the public acceptance of the so-called “scientific consensus”.
Anyone with a modicum of knowledge in the area knew that the graph had to be wrong as it over-turned the existing scientific consensus of the magnitude of the climatic fluctuations over just the last thousand years on the basis of just one slender line of proxy evidence.
The graphing process was quickly shown to be statistically incompetent, but subsequent revelations has shown it to be at best sleight of hand (what those involved “charmingly” refer to as a trick) or at worst fraudulent.
The Hockey Stick graph is the best litmus test of whether someone is honest or knowledgeable about global warming. If they defend it, then they are either not one nor the other, and possibly not both.
This video of Professor Richard A Muller lays the fraud issue out much better than I can. (H/T Roger Pielke Jr).