I have spent the afternoon in AGW skeptic land, viewing the hacked (or should that be "leaked") CCU emails. I did not find any amazing death blow to AGW theory. What I did find was a record of people in the throes of CyberFrustration trying to get the computer to do what it was paid to do. So I did a search on one sample page for "aaa" and came up with several instance of "Aaargh" or variant thereof, as the poor b'stard got another garbage out response from the data. I really did find this, but cannot find the page now*. There are scores of pages to search through.
The emails give an impression of the enormous complexity of the work done, and also an impression that the results were being filtered in favour of those that matched a recent upturn of temperature, but only an expert, after a long time re-working the data, could give a verdict on this.
There is an interesting, balanced piece by Judy Curry here .
She calls for transparency in climate science, which is a very good idea.
She also describes the tribalism that has grown up in the scientific community, with two groups, the pro AGW and anti-AGW. This is accurate imho. The debate has been emotional, with plenty of spleen vented in both sides, and this has not contributed to good science.
This tribalism is not unique to climate science. It happens in all areas.
There was a massive, lifelong clash between two pharmacologists in the early 20th century over muscarinic receptors.
There was a decade long clash over psychiatric depression in the sixties, whether it was one or two entities. The protagonists kept producing ever-larger studies, alternately producing graphs which showed either a camel (one hump) or a dromedary (two humps), depending who had done the work.
There was a mighty argument before it plate tectonics was accepted by geologists.
And so on. That's science. It is not the objective, clean cut clarity that films and news media present.
My conclusion is that global is an immensely complex system, with numerous inputs, that CO2 remains a greenhouse gas, that levels of CO2 have indeed gone up, and that global temperatures are also going up.
After this afternoon's excursion I also have the impression that the Mediaeval warm period was global, not local, and was probably nearly as warm as now, that solar inputs have maybe been underestimated, and that denialists are still prone to cherrypicking.
Finally, it remains the case that the best thing to do is to decarbonise the world economy, because of AGW, acid rain, acid oceans, and peak oil.
[Update: there is a summary of the juicy bits from the emails on Bishop Hill's blog here. It is detailed, and confirms the initial impression: they show that the scientists are human, but the basic science of global warming - that humans have changed the greenhouse composition of the atmosphere, and we are seeing the effects of that changing now - remains).
*[Update 3/12/09: Well, it seems I had stumbled on the computer code page -_the "Harry Read Me.txt page.
Pajamas Media, who seem to be sane, have had a programmer look at what the guy above (let's call him Harry) was doing. Apparently he was trying to organise data with a programme that was not fit for purpose. Newsnight have picked it up the story.
OK. What we have to do is pull all the CRU work out of the equation. I am confident that the Spaghetti Graph, relieved of one or two strands, will still show significant warming.
The CRU work may or may not stand up to review. That will have to wait. The vital action now is to get a revised, CRU-free Spaghetti Graph where people can see them).
New Scientist view on this.