Actually, as with any scientific hypothesis, you can't prove AGW.
Ugh. Yuk. Seriously, I thought you were a scientist? Where did I say anything about proving AGW (beyond quoting desparation from Ben)? The word "proof" belongs to formalisations such as mathematics, not to science, so we're off to a bad start here anyway. What you mean is provide supporting evidence for. You can't prove it, but you can provide evidence supporting a hypothesis with *some probability* that you are wrong. Of course, as mhaze correctly notes, "AGW" isn't a hypothesis in itself.
Disproving it is trivial.
Ugh. Yuk. There's that "proof" word again. Falsifying a hypothesis is not the same as disproving an effect. For example, if we are seeking a to provide evidence supporting an effect (e.g. AGW, biblical predictions) in a noisy structure (e.g. global temperatures, biblical text) then it is obviously impossible to "disprove". All we can do is show that the evidence is inadequate to support the claim.
Since I've started on it, let's take the Torah codes as an example. I like this example. It has many similarities to the AGW case. When Randi debunked the Torah codes, did he prove that the bible does not contain predictions? No he did not. Because that is impossible to do. Let's elaborate.
Someone else made the claim that the bible contained predictions, and they provided evidence of that claim. They claimed to show that the distances between skip codes in the original biblical text for dates and descriptions of certain events that occurred after the bible was written were so close that they were highly unlikely to have occurred by chance alone.
Randi came along, looked at their models, and demonstrated that their statistical model was in error. Essentially, there was more than one way to describe the events which resulted in additional degrees of freedom, allowing the experimenter to bias the results through selection. To resolve this, either the model can be corrected or the experiment can be repeated. In this case I believe the experiment was repeated (clearly not feasible for AGW), it was shown that the results were quite likely to have occurred by chance alone.
Now, does this disprove that the bible contains predictions? No! Absolutely not. It may be that the effect is smaller than originally claimed, and that more samples, or a more powerful statistical test, could detect an effect. Or it could be that the predictions manifest themselves differently. All Randi did was to show that the evidence provided had another trivial possible explanation - that the results could have occurred by chance alone, and were not significant. This is most certainly not "disproof" of the idea that the bible contains predictions, but it is a clear demonstration that there is no credible evidence supporting the idea. The distinction here is very important.
So then we get on to the AGW "hypothesis". As mhaze rightly pulls you up on, AGW is not a "hypothesis". A hypothesis is a specific test we develop based on our theory. An example of a hypothesis we might form is that we might hypothesise that global temperatures will increase as a result of AGW. OK, that's a testable hypothesis ("AGW" is not). That argument is addressed by Cohn and Lins in a method analogous to the method used to discredit the evidence in the Torah codes.
Of course, rising global temperatures are a necessary but not sufficient test - other things could cause the warming. And that is the point of the Cohn and Lins test. Could LTP in the hydrological cycle also be the cause of the warming? Their results show that yes, this is a plausible explanation. The magnitude of effects (clouds, water vapour) are also consistent with the findings.
So, we are not disproving anything (because it isn't possible). We assessing whether the evidence is valid or not. And so far, there has been no reliable falsification of the evidence supporting the LTP theory. Halley argues the effect appears too small but this comes with huge caveats, as the data he uses have underlying problems.
So we have two competing theories, neither of which is falsified. Of course, the correct scientific thing to do would be to seek a test which resolves the predictions of the two models. But on JREF we just get people asserting black is white. Great way to do science, people.
As it stands, there is a huge amount of evidence supporting the AGW hypothesis, so if you think there's no scientific reason to think AGW is correct, then you must have spent very little time informing yourself on the matter.
If you think you have accurately characterised my ideas, or that you have even a basic understanding of hypothesis testing, then you have clearly spent very little time informing yourself on the matter.
Anyway, please feel free to tell me which of the huge amount of evidence suppoorting AGW is inconsistent with the warming being caused by LTP in the hydrological cycle. Because I'm not aware of any. That doesn't mean it doesn't exist, of course. But at least I'm willing to be educated. No evidence of that on your part.
... what a maroon...
