Can global warming deniers answer a simple question?
I recently asked a simple question about the 'hockey stick' and not a single denier answered it. http://answers.yahoo.com/question/index?qid=20090918114243AAN0Gwb
But I'll give them the benefit of the doubt and assume they didn't understand the question. I'll break it out as simply as possible.
1) The 'hockey stick' was criticized on two points by both McIntyre and McKitrick and the Wegman Report.
a) their principle component (PC) statistical analysis b) their use of bristlecone pine data
2) Wahl and Ammann did an analysis of the data taking these criticisms into account and found
a) "reconstructed temperatures are demonstrated to be virtually unaffected by the use or non-use of PCs"
b) "Even in the absence of [bristlecone pine data], the scenario 3 reconstructions in the 15th century do not exhibit large enough excursions in the positive direction (in relation to the 20th century instrumental record) to yield a double-bladed hockey stick result that diminishes the uniqueness of the late 20th century departure from long-term trends."
The criticisms of the 'hockey stick' were 'a' and 'b'. Wahl and Ammann (and Mann et al. 2008) addressed 'a' and 'b' and found that they 'hockey stick' shape remained. Further, every single peer-reviewed global temperature reconstruction has shown the same basic 'hockey stick' shape and shows current temperatures at least 0.5°C hotter than during the Medieval Warm Period. http://www.ncdc.noaa.gov/paleo/pubs/ipcc2007/fig6-10b.png
So the question is, if the 'hockey stick' is wrong, why does the shape remain when taking the Wegman criticisms into account, and in every other global temperature reconstruction?
Eric c2009-09-19T21:55:42Z
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First of all Wahl and Ammann is not "independent" study. They are Mann's recent co-authors and Ammann was a PhD student under Mann and Bradley. Their article simply fleshes out points that Mann himself had already made in his correspondence with Nature - although Mann is nowhere mentioned in the acknowledgements - presumably in an attempt to make the study seem "independent" - a claim that Wegman rejected sarcastically.
But since you are an expert on statistical analysis, here is a rebutall by McIntyre. Now you tell me what is wrong, with his analysis.
http://www.climateaudit.org/?p=798
I then urge you to do a search of Wahl and Ammann on his web site to find out even more criticisms. Now tell me in your own words what is wrong with his analysis. Can you do that? I do not think so. But then again you are not a statistician. But you are going around around asking us for rebuttals to Wahl, knowing full well that non of us are qualified to answer your question. Since no one can, you will then dance around and declare victory and say that the case is closed. Very very typical alarmist tactic.
Why do they have the same shape. Also from the Wegman report:
“It is clear that many of the proxies are re-used in most of the papers. It is not surprising that the papers would obtain similar results and so cannot really claim to be independent verifications.”
Loehle, used non tree rings proxies and came up with a different conclusion, even in his revised edition.
So far it seems that all the proxy data says that average temperatures during the Medieval Warm Period didn't reach worldwide average temperature today.
This is pretty much in line with the summary for the book 'The Medieval Warm Period' (which collected together research papers etc). Other papers support this, but they say that these warm periods weren't always going on at the same time. Eg it might have been warm in Europe for 30 years, but only warm in China 50 years after that, say.
Eg Hughes & Diaz (Climatic Change, 2005): 'These warmer regional episodes were not strongly synchronous.' similar to Hughes & Lowery (AMBIO, 2000).
Ottawa Mike: there are nearly 400 vineyards in England, going as far north as Lancashire & Yorkshire: http://www.yell.com/s/wine+producers+and+vineyards-blackburn-lancashire.html
A Kentish Vineyard started in 1991. I assume they based their economic decision on the temperature of the years before; ie the late 1980s, when temperatures in England were (on average) about 0.5+C cooler than they have been for the 2000s.
Corky, does past climate change (regional or otherwise) mean rapid holocene warming must be natural and desirable in today's human-dominated world?
Peter: http://www.realclimate.org/index.php/archives/2008/06/north-pole-notes/comment-page-1/#comment-90966 (this is a comment on an RC article, not from one of their nasty "biased" climatologists).
Mike: There have also been vineyards in England for the entire 20th century through today. And please tell me, what were the Vikings growing, where in Greenland, what was their productivity like, and how does that translate to global average temperature? Please provide a SCIENTIFIC source.
But all the little anecdotes (which often turn out to be falsehoods or partial-truths) aside, is any denier going to actually answer the topic question?
Ampat, maybe you should have a closer look at the petition project: http://greenfyre.wordpress.com/denier-vs-skeptic/denier-myths-debunked/the-oregon-petition/ http://timlambert.org/2004/05/oregonpetition/ http://chriscolose.wordpress.com/2008/05/22/one-more-petition-still-a-consensus/
I am going back to a few months ago when you and your other alarmists stated that indeed the Mann "hockey stick" was incorrect and you had reasons for it then why Mann was incorrect in his assumptions and why were the deniers keep bringing it up. Instead of wasting my time trying to find that discourse why don't you or one of your people locate it for us to answer your own question.
I believe Ottawa Mike's answer answered your question which was by the way just another rant as you already concluded months ago that it was false. So do you really have this much time on your hands to spew this propaganda to the people on this site?
I'm not a denier so I won't answer the question. I will just say though, that i am pleased there is still someone out there pushing the petition project. What a goose.