The Canadians, McIntyre and McKitrick, then published a paper purporting to uncover serious methodological flaws and problems with data sets used.
Everything from this point on is hotly disputed and highly technical.
All the claims made by M&M have been rebutted in detail by many other climatologists; M&M insist they are completely in error. All of it fits nicely with the expectations of both sides of the global warming issue, both the conspiracy theorists and the champions of peer review.
If you want to evaluate the issue for yourself, and do it fairly, you must read the copious material at the sites mentioned above. You must also be prepared to dig into dendrochronology and statistical analysis.
Where does that leave the rest of us -- you know, the ones with lives?
I confess immediately that the technical issues are over my head. I don't know PCA from R^2 from a hole in the ground. But the most critical point to remember, if you are concerned about this for its impact on the validity of AGW theory, is that the fight is over a single study, published eight years ago, focused on paleoclimate. It verges on historical minutia. If you feel the study may be tainted, simply discard it.In other words "Don't let troublesome mathematics trouble your tiny little brain, I never let it bother mine. It's really complicated and you should just trust us instead of actually wasting hours of your precious time actually educating yourself on statistics." In fairness they do at least link to climate audit so you can have a look but they don't make any attempt to explain what the problems were in simple langauge.
What's more, NASA GISS takes explicit steps in their analysis to remove any such spurious signal by normalizing urban station data trends to the surrounding rural stations. It is a real phenomenon, but it is one climate scientists are well aware of and have taken any required steps to remove its influence from the raw data.Except that when you look at Surface Stations, Climate Audit etc. you realize that these stepts to remove UHI are, to be kind, less than completely error free. Furthermore UHI is only one of the problems with the global surface temperature records but they don't bother to mention (as far as I can see) all the other problems with the raw data that have become apparent such as canvas buckets, non-existant stations, poor siting, sloppy measuring etc.
Post-normal science, on the other hand, acknowledges that while we’re doing our normal science, some groups want or need to know the answers well before normal science has resolved the deep inherent uncertainties surrounding the problem at hand. Such groups have a stake in the outcome and want some way of dealing with the vast array of uncertainties, which, by the way, are not all equal in the degree of confidence they carry. Compared to applied science and professional consultancy, post-normal science carries both higher decision stakes and higher systems uncertainty[...]
The climate change debate — particularly its policy components — falls clearly into the post-normal science characterization and will likely remain there for decades, which is the minimum amount of time it will take to resolve some of the larger remaining uncertainties surrounding it[.]However while cost-benefit risk analysis is interesting it doesn't help us grow new minds that can investigate the data and analyses we have seen so far. Statistics is a complex field (as a studious amateur I get lost in some of the more complex reasoning about PCA although unlike the Grist writer I do know the difference between it and a hole in the ground) and it is very easy to make serious errors. Surely it would be sensible for climate change activists to create a bunch of statistically educated folk who do know the difference between PCA and a hole and who could therefore take the arguments of McIntyre, McKitterick & co. on. Indeed the total lack of statistical topics at that site (a google search shows that this is the ONLY statistics topic anywhere on the site) simply adds to the impression that enviroMENTALists are far from interested in validating the dire predictions that they rely on to get their agenda accepted by the rest of us.
Some of the most vocal skeptics have done relatively little recent peer-reviewed scientific research on the topic, and some have had their voices amplified via financial support from industries opposed to any government regulation or taxation of greenhouse gas emissions. Others do have training and experience, at least in some aspects of the wide-ranging issue, and are not bankrolled by industry. But overall, their number represents a distinctly minority position in the ongoing and normal colloquy among scientists about the evidence of climate change and its likely impacts.
Climate-change modeling is less certain in forecasting impacts on a regional scale, and in assessing warming's role in extreme weather like hurricanes. But the regional resolution of the models is improving, and the 2007 IPCC report offered more detail than previous ones. Researchers also are busily assessing regional vulnerabilities to possible climate-change scenarios. So while there remain more robust debates in these areas, new research is constantly adding new layers of understanding. One needs to try to stay current on the latest published studies, on who's doing them and who's funding them.
There are a number of climate-change skeptics, less-often quoted perhaps than some more vocal ones discussed later, who have more substantial climate science research publications and who have accepted little or no fossil industry and advocacy group money. These typically include:...Followed by a mere three names (Christy, Lindzen, Grey).