A perfect example of all three can be found in the comments to this op-ed piece by MIT Professor of Meteorology Richard Lindzen.
No argument there. But then Lindzen does the unforgivable, at least in the eyes of the AlGoristas: He questions the validity of the claims that GW is real and that we, human beings, are the sole cause.
The general support for warming is based not so much on the quality of the data, but rather on the fact that there was a little ice age from about the 15th to the 19th century. Thus it is not surprising that temperatures should increase as we emerged from this episode. At the same time that we were emerging from the little ice age, the industrial era began, and this was accompanied by increasing emissions of greenhouse gases such as CO2, methane and nitrous oxide. CO2 is the most prominent of these, and it is again generally accepted that it has increased by about 30%.
He goes on to make his case, showing the science is, at best, very weak and that the models are useless because they give too much weight to some factors and not enough (or none) to others. It is this that drove the comments of the faithful to go over the edge and cease being a debate. One comment in particular sticks out, trying to discredit Professor Lindzen despite his impeccable credentials and expertise in the science of climate.
At this point there is no basis for alarm regardless of whether any relation between the observed warming and the observed increase in minor greenhouse gases can be established. Nevertheless, the most publicized claims of the U.N.'s Intergovernmental Panel on Climate Change (IPCC) deal exactly with whether any relation can be discerned. The failure of the attempts to link the two over the past 20 years bespeaks the weakness of any case for concern.
So the argument put forward is that he's too old, which means he is incapable of understanding the science (and the math) behind climate research? The commenter, one Arthur Kreitman, believes that just because Professor Lindzen is 'old' that he is out of touch, implying perhaps that he is senile. He also assumes that the professor's knowledge ossified and that he's learned nothing new since 1964! He is assuming based upon facts not in evidence. Kreitman's comments are a perfect example of an ad hominum attack. Don't argue the facts, argue instead the qualifications of the one you disagree with and make the allegation that he is incapable of understanding the science behind the fraud that is AGW.
At age 70, Professor Lindzen just isn't current on the research, it's that simple. He's done distinguished work in the past, but his current opinions [are] at best outliers. He's not involved in the current research.
His view is that the computer models are unreliable. Considering the capabilities of computer modeling at the time he received his Ph.D, which was 1964, that view is understandable. His expertise in the state of computer modeling is just outdated.
But on the other hand, I liked this one because, if nothing else, it explains a few things I've noticed, too.
The exact same thing happened to me, too!
I too have a theory and a model. Through careful observation of the night sky, I have determined, within a few percentage points of perfection, the winning numbers for every lottery drawing over the last 20 years. But something always goes wrong, and the numbers drawn are not quite right. I've decided that this is clearly the work of extraterrestrials, who are screwing with the night sky to fudge my numbers and deny me my rightful winnings. I had all the data to prove this, but I threw it away when my computer's hard drive got overloaded. Nevertheless, my theory is a fact, because I say it is. And since no one has ever published data proving me wrong in a peer-reviewed journal, no one can say I'm wrong.