James,
I've been watching this thread with interest, and I think you are on the wrong end of this one.
>Yes, but that rather indicates what the value of the petition was. It
>did not represent scientific enquiry, but opinion, like all petitions.
>It is of interest what scientists think outside of their discipline, but
>hardly decisive. In any event, questions of fact are not decided by
>weight of numbers, but by reference to the subject matter.
But their opinions were in reference to their area of expertise - what's wrong with that? The best way to assess a potential problem and any likely consequences is to consult the people who work in appropriate fields, which is just what the IPCC assessment report appears to have done.
>Well, this in itself speaks volumes. When one tries to win the argument
>by characterising your opponents motives rather than addressing the
>content of what they say, then we are plainly in the realm of a
>political controversy, not a scientific enquiry.
Only this is precisely how you have argued against the IPCC, trying to delegitimize the report by saying it is a political document and referring to the biased nature of the UN. I haven't seen you present any specific arguments refuting the IPCC position yet. You've said, in effect, look at the source, which is all anyone else has done in reference to Michaels and Balling.
But DiPaola went well beyond pointing out their industry funding. He actually did refute Michaels and Ballings' claim that atmospheric and surface temperature data are not in agreement. The scientific consensus seems to be they have misinterpreted the data, as opposed to some sort of massive coverup which the two skeptics are boldly trying to expose.
DiPaola also mentioned their suspect arguments that large increases in atmospheric CO2 concentration are a very good thing, which, according to him, were very poorly argued in their book.
Now, you may disagree with these assertions, but they certainly do address Michaels' and Balling's positions, what they say, with respect to global warming.
>Not I but Guardian environment
>correspondent John Vidal writes, anthropogenic global warming is an
>unproveable hypothesis.
<Shrug> Most hypotheses are unprovable. They can only be refuted.
Brett