Posted on 05/13/2005 7:27:56 AM PDT by cogitator
Media Advisory: The Hockey Stick Controversy
New Analysis Reproduces Graph of Late 20th Century Temperature Rise
May 11, 2005
BOULDER—Caspar Ammann, a paleoclimatologist at the National Center for Atmospheric Research (NCAR), is available to comment on the so-called hockey stick controversy discussed by Stephen McIntyre and Ross McKitrick today at the National Press Club in Washington, D.C. The hockey stick refers to the shape of a frequently cited graph of global mean temperature that shows a rapid rise between 1900 and 2000 after 900 years of relative stability. The graph first appeared in a research paper by Michael Mann, Raymond Bradley, and Malcolm Hughes published in the journal Nature in 1998.
Ammann and Eugene Wahl of Alfred University have analyzed the Mann-Bradley-Hughes (MBH) climate field reconstruction and reproduced the MBH results using their own computer code. They found the MBH method is robust even when numerous modifications are employed. Their results appear in two new research papers submitted for review to the journals Geophysical Research Letters and Climatic Change. The authors invite researchers and others to use the code for their own evaluation of the method.
Ammann and Wahl’s findings contradict an assertion by McIntyre and McKitrick that 15th century global temperatures rival those of the late 20th century and therefore make the hockey stick-shaped graph inaccurate. They also dispute McIntyre and McKitrick’s alleged identification of a fundamental flaw that would significantly bias the MBH climate reconstruction toward a hockey stick shape. Ammann and Wahl conclude that the highly publicized criticisms of the MBH graph are unfounded. They first presented their detailed analyses at the American Geophysical Union’s Fall Meeting in San Francisco last December and at the American Association of Geographers Annual Meeting in Denver this year.
McIntyre and McKitrick’s papers were published in Energy and Environment (2003 and 2005) and in Geophysical Research Letters (2005).
Go to linked article for related links
If the authors have made mistakes, they'd like to know about it, I'm sure.
Well the first mistake I would like to point out is that you can't MAKE UP temperature data from 1400 to 1900 and then use accurate REAL DATA for 1900-2000, and expect anything useful - unless you define 'useful' as a meaning a good propoganda tool.
The temperature data from 1400-1900 (and earlier) consists of calibrated temperature proxies. That's part of the method described as "robust". The data is not "made up" in the sense of contrived out of nowhere.
Can someone post a picture of Ann Coulter here
I would rather see that then this dribble.
Dont you see that you have to graph data taken the SAME WAY (not two different ways) in order to have a meaningful graph?
OK, so use "calibrated temperature proxies" for all the data
Now back to our previously-scheduled topic.
Proxies? as in not the real thing?
Read the papers or ask the authors why that isn't a useful method.
Proxies as in: there isn't any other way to estimate global temperatures then. Read the papers.
I clicked on the link and it linked me to the Wahl-Ammann press release, to two Wahl-Ammann studies, and a Wahl-Ammann website, but not to anything from McKitrrick/McIntyre. In other words, they don't link to criticisms of the "hockey stick", only to defenders. With only one side presented, it's not worth investigating further.
I love the way, they cut it at the 14th century. If you go back to the 12th, you'll find you have a two headed hockey stick.
Cool, If the data does not fit the hypothesis then get new data.
I agree! By the same methodology used to get 14th century temperatures shows higher temperatures in the 7th to 11th centuries higher than now!
A couple things...
Looking at the graph, it appears that either the "calibrated temperature proxies" ended circa 1975, or they exactly matched the recorded temperatures. Seems like it would be beneficial to see how closely those proxies matched the recorded temps over the last 30 years.
I'd be interested in knowing what, exactly, the proxies are. I drilled down to a couple of articles referenced in this one, and could't find out. Don't have time to pursue it further today, although I'd like to do some more research later.
Lastly, the "little ice age" which occured broadly from the mid 14th to the mid 19th centuries, doesn't seem to be indicated by this climate model. Yet, the "warming" that has occured since 1900 would appear to be dramatic. I don't pretend to understand this, but shouldn't we being experiencing a heatwave of terrific and devastating proportions by now based on the graph, especially considering the little ice age doesn't seem to reflect any trend change at all? Makes me wonder if the proxies chosen are representative of actual temperatures at all - perhaps there are other proxies that would give different (and potentially more accurate) results.
Data plot from a subsequent paper.
The other side of the story:
http://www.marshall.org/article.php?id=293
D. Deming, Science 1995
"With the publication of the article in Science [in 1995], I gained significant credibility in the community of scientists working on climate change. They thought I was one of them, someone who would pervert science in the service of social and political causes. So one of them let his guard down. A mojor person working in the area of climate change and global warming sent me an astonishing email that said "We have to get rid of the Medieval Warm Period.""
Anyone know what it looks like when 1999 through 2005 are included?
The calibrated temperature proxies end about 1890. The instrumental record begins then.
I'd be interested in knowing what, exactly, the proxies are.
Tree rings augmented with coral growth rings and something else that I don't recall at the moment (ice cores?).
Lastly, the "little ice age" which occured broadly from the mid 14th to the mid 19th centuries, doesn't seem to be indicated by this climate model.
That's part of the controversy, but the coldest period in the Mann et al. record occurs during the broader period known as the Little Ice Age. Much of the controversy is based on the observation that the method used reduces the amplitude of temperature variability.
Not much different. 2004 was the second highest global temperature in the record, after 1998.
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