People need to be in this debate regardless of whether they are climate scientists or scientists at all. Indeed, as I argued in an earlier post, climate is an issue that is much too big for climate scientists. We are, therefore, all dependent on serious debate and, in fact, coverage of a range of research in natural and social sciences and the conclusions drawn from it.

To get to grips with the subject at any level, most people need the assistance of intermediary communicators between them and the scientist. If you want the references, go to Fred Pearce’s article cited in my first reply to you, also cited in my original blog-post albeit by a different route (referring to all of Pearce’s series on the controversy, whereas the reference I gave you on Friday was to his specific report on the hockey stick controversy). In both cases, you will find many references. Much more convenient for you than me putting the links in here.

Interestingly, Pearce’s coverage is regarded as unfair by some climate scientists (go to the RealClimate posts cited in the blog-post), which makes me think his grudging confirmation on the hockey stick is especially significant. One more key point: you have again mentioned reviews of the hockey stick graph but Pearce’s point is actually about replication of the research findings.

But I was really asking you, in a roundabout way perhaps, for proper references about the reviewers of the hockey stick graph.
Who replicated Manns graph? Did they go back to the base data? Why does the graph contradict other studies? Why did the IPCC suddenly drop the mainstream studies and adopt Mann’s research without explanation.
I mean you are not going to sit back there and believe what other people tell you on such an important matter without digging around for some verifiable facts are you?
Verfiable data would be the thesis, or reports of these reviewers exposing their methods and depth of review etc. not someones blog saying this has been done.

Cheers

Roger

To quote someone elses blog which has no or limited references is fairly thin evidence one way or the other.

“”There is sufficient evidence… of past surface temperatures to say with a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years. Less confidence can be placed in proxy-based reconstructions of surface temperatures for AD 900 to 1600, although the available proxy evidence does indicate that many locations were warmer during the past 25 years than during any other 25-year period since 900.”

The findings that Manns study was accurate for the last 400 years also means little except that it implies that it was inaccurate previous to the 17th century.

Now all the fuss about Mann’s graph was that it somehow got rid of the Medieval Warm Period (which is about 1000 years ago) which is certainly convenient for the IPCC, because if the world has been warmer than the present before in history (when the only human induced CO2 was produced by some sword sharpening by a minority), its a little difficult to blame Global Warming on anthropogenic CO2.

Before Manns “Hockey Stick Graph” was adopted by the IPCC they used the graph at http://rogerfromnewzealand.files.wordpress.com/2010/01/ipcc1990-graph1.jpg?w=480&h=252
Sorry I have to use my own blog reference there because although this graph appeared in the IPCC 1990 report Fig 7.1 c it is no longer on their website (They cite “out of print”).
The fact that this critical piece of information was replaced subsequently by Mann’s graph without notice, explanation or reason is actually suspicious in itself.

Questions about the Medieval Warm Period.

1. Was it warmer than the present?
Please read my well referenced blog at http://www.rogerfromnewzealand.wordpress.com

2. Was it only local to Greenland?
This link is anecdotal but compelling nonetheless
http://tenthmedieval.wordpress.com/2010/01/09/darn-climate-sceptics-get-out-of-my-field/
Of course the medieval warm period shows up in other literature as well, such as
http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/CookPalmer.pdf
or if you want to read “Grove, J.M. 988:The little ice age.by methuen.
Warm periods are well documented by other cultures eg http://www.springerlink.com/content/gh98230822m7g01l/ etc where the historical history of China’s climate is examined.
Medieval warming and earlier periods are even suggested in the Antarctic Ice core project.
http://www.pages.unibe.ch/products/newsletters/2009-1/special%20section/science%20highlights/Bentley+Hodgson_2009-1(28-29).pdf, and suggested in the Indo Pacific Warm Pool research.

And of course the Medieval Warm Period was not the only warmer period in recorded history. During the even earlier Holocene Optimum period, a very warm period which coincided with our stone age (and is consistent with some of the findings at Schnidejoch) the Sahara was lush and fertile. Do some reading on that maybe? http://www.jstor.org/pss/2997337 is a good start.

So I hope you understand now why we find Mann’s Hockeystick graph somewhat unbelievable and definitely not vindicated by its reviewers so far.

Cheers

Roger

Really?

I am interested to see your references upon which you made that statement.

Looking forward to your reply.

Cheers

Roger