Tag Archives: Dendrochronology

Oh Mann! Paper demonstrates that tree-ring proxy temperature data is ‘seriously compromised’

Michael Mann won’t be happy about this. A new paper now in open review in the journal Climate of the Past suggests that “modern sample bias “has “seriously compromised” tree-ring temperature reconstructions, producing an “artificial positive signal [e.g. 'hockey stick'] … Continue reading

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Posted in Paleoclimatology | Tagged , , | 112 Comments

The East Anglia Rococo

Steve McIntyre has a new analysis up, one that has a strong headline. Though as he says, “not in so many words”, but more about techniques and exclusions. He writes: Briffa Condemns Mann Reconstructions

Posted in Paleoclimatology | Tagged , , , , , , , | 54 Comments

Dendros stick it to the Mann

UPDATE3: professor Rob Wilson leaves some scathing comments about the Mann paper. See below. UPDATE2: There’s been some additional discussion on the dendro listserver, and it seems quite clear now that the scientists in the dendrochronology field don’t think much … Continue reading

Posted in Michael E. Mann, Paleoclimatology | Tagged , | 180 Comments

Mann’s hockey stick disappears – and CRU’s Briffa helps make the MWP live again by pointing out bias in the data

Shock, awe. Untruncated and unspliced data used in a new paper from Briffa and Melvin at UEA restores the Medieval Warm Period while at the same time disappears Mann’s hockey stick. Here’s figure 5 that tells the story: Look at … Continue reading

Posted in Climategate, Michael E. Mann, Paleoclimatology | Tagged , , , , , , , | 483 Comments

New isotope based temperature reconstruction using McIntyre’s ‘Starbucks hypothesis’ tree core samples

A new paper in GRL published Sep 6th Secular temperature trends for the southern Rocky Mountains over the last five centuries makes use of some tree core sample data gathered by Steve McIntyre and Mr. Pete. Readers of WUWT and … Continue reading

Posted in Citizen science, Michael E. Mann, Paleoclimatology | Tagged , , , , , | 137 Comments

This is what global cooling really looks like – new tree ring study shows 2000 years of cooling – previous studies underestimated temperatures of Roman and Medieval Warm Periods

Since Princeton’s Dr. Michael Oppenheimer conflated weather with climate last week, proclaiming a short lived heat wave as “This is what global warming really looks like” in a media interview, it seems only fair to show what real science rather than … Continue reading

Posted in Global cooling, Paleoclimatology | Tagged , , , , , , , , | 219 Comments

Linking the ENSO and PDO induced rainfall of the Pacific Northwest to proxy data in tree rings and lake sediments

From Penn State , another Mann paper with proxy sets, and a divergence problem. At least they are talking about the MWP, or as they call it, the Medieval Climate Anomaly which had been erased in previous papers Mann had … Continue reading

Posted in Climate data, Paleoclimatology, PDO | Tagged , , , , , , , , | 147 Comments

The Neo Paleo Twitter war of Mann -vs- D’Arrigo

It seems that Columbia’s Rosanne D’Arrigo thinks Mann’s tree ring study isn’t representative proxies for volcanic eruptions, nor good for dendrochronology, though Mike Mann seems to think so. This Twitter interchange via Alexandra Witze from the AGU Chapman Conference on … Continue reading

Posted in Michael E. Mann, Paleoclimatology | Tagged , , , , , , , | 71 Comments

Revkin on the Gergis et al ‘on hold’ affair

I promised Andrew Revkin yesterday that I’d give his post on Gergis et all some attention, because he’s done a good job of summarizing it all, plus getting some other angles, such as that of Retractionwatch. I was especially pleased … Continue reading

Posted in Paleoclimatology, Peer review | Tagged , , , , , , , | 58 Comments

Yamal that hurts! CRU gets touchy, responds to McIntyre and Montford without naming them

From the “he who must not be named” department, comes this sure to be future McI-fodder. UEA/CRU responds in a press release, authored by Tim Osborn, an excerpt: =========================================================== Tim Osborn comments on “Yamal, Polar Urals and Muir-Russell” Recent accusations … Continue reading

Posted in Peer review, Satire, The Yamal Deception | Tagged , , , , , , , , , | 90 Comments

McIntyre rebuts Schmidt’s Rant on Yamal

By Steve McIntyre Two days ago, NASA blogger Gavin Schmidt posted an extended rant against me at Real Climate, a rant directed in part at my recent poston Yamal. I’ve now looked through his post carefully and, beneath Schmidt’s fulminations, … Continue reading

Posted in Gavin Schmidt, Paleoclimatology | Tagged , , , , , , , | 30 Comments

Another reason trees don’t make good treemometers – new tree ring data bias discovered

[Note: My first post in which I had written commentary mysteriously lost all of its content, posting nothing but white space. This is some sort of internal wordpress error, but has never happened before. I have some elements restored below, … Continue reading

Posted in Paleoclimatology | Tagged , , , | 76 Comments

Mann: Trees aren’t behaving like I want them to – volcanoes to blame

From Penn State Tree rings may underestimate climate response to volcanic eruptions Some climate cooling caused by past volcanic eruptions may not be evident in tree-ring reconstructions of temperature change because large enough temperature drops lead to greatly shortened or … Continue reading

Posted in Paleoclimatology | Tagged , , | 117 Comments

The behind the scenes bumbling of the hockey stick

Mann oh Mann. Tom Nelson continues to wade through the 5000+ Climategate 2 emails. I’ve selected a few he’s highlighted in the vein of behind the scenes discussion of Dr. Michael Mann’s infamous “hockey stick” which claimed we were living … Continue reading

Posted in Climategate, Michael E. Mann, Paleoclimatology | Tagged , , , , , , , , , | 93 Comments

Paging Mike Mann – your dendrochronologist will see you now

Tom Nelson has another Climategate 2 email well worth reading Dendrochronologists get spanked by guy with expertise in tree physiology and wood anatomy ClimateGate Email 1738 “However, there are bounds to dendrochronology, as there are to every field of investigation, … Continue reading

Posted in Michael E. Mann, Paleoclimatology, Peer review, Post-normal science | Tagged , , , , , , , , | 148 Comments

Mann hockey stick co-author Bradley: “it may be that Mann et al simply don’t have the long-term trend right”

Tom Nelson spots a gem in the Climategate 2 emails: Hockey stick co-author Ray Bradley: “it may be that Mann et al simply don’t have the long-term trend right”; “I hedge my bets on whether there were any periods in … Continue reading

Posted in Climategate | Tagged , , , , , , , | 149 Comments

In China, there are no hockey sticks

Reposted from Jo Nova’s site Chinese 2485 year tree ring study shows shows sun or ocean controls climate, temps will cool til 2068 A blockbuster Chinese study of Tibetan Tree rings by Lui et al 2011 shows, with detail, that … Continue reading

Posted in Paleoclimatology | Tagged , , , , , , , | 264 Comments

Internal dissent: “Personally, I think that the tree ring records should be able to reproduce the instrumental record”

Severinghaus and “Hide the Decline” By Steve McIntyre One of the very first contributions to realclimate was an FAQ from Jeff Severighaus on Dec 3, 2004. A year earlier, Severinghaus attempted (unsuccessfully) to get an explanation of the “divergence” problem from … Continue reading

Posted in Uncategorized | Tagged , , , , , , , | 43 Comments

John L. Daly’s message to Mike Mann and The Team

Ric Werme writes in comments: When I realized the Climategate 2009 Emails went back many years, one of the first things that occurred to me was there might be Emails from John Daly. He died before I became involved in … Continue reading

Posted in Climategate, Paleoclimatology | Tagged , , , , | 85 Comments

Roman Period “megadrought” found in the USA southwest

From the University of Arizona, one wonders how such a thing could happen when CO2 was at “safe” levels. They are using bristlecone pines again, which may very well be a better proxy for rainfall than for temperature. At least … Continue reading

Posted in Paleoclimatology | Tagged , , | 194 Comments

Sheep study confirms a premise of McIntyre & McKittrick 05

Yesterday, I published a press release titled Tree ring widths more affected by sheep than temperature in which researchers in Norway published a peer reviewed study stating: “We found tree ring widths were more affected by sheep than the ambient temperature at … Continue reading

Posted in Paleoclimatology | Tagged , , , , | 40 Comments

Tree ring widths more affected by sheep than temperature

From Wiley-Blackwell, via Eurekalert, something just plain surprising. Nibbling by herbivores can have a greater impact on the width of tree rings than climate, new research has found. The study, published this week in the British Ecological Society’s journal Functional … Continue reading

Posted in Paleoclimatology, Satire | Tagged , | 71 Comments

UEA’s response to EIR/FOIA requests – It depends who you are

Guest post by Richard Brearley This post is written to publicise an interesting anomaly in UEA’s (University of East Anglia) treatment of requests sent to it under the Environmental Information Regulations. Readers should know that my interest is only in … Continue reading

Posted in FOI | Tagged , , , , | 43 Comments

Trees show no rainfall pattern in last century

I’ve always said that trees are a better proxy for rainfall than temperature. Just looking at how trees cluster around water sources can tell you this. From the Hockeyschtick: New paper shows no increase in precipitation over past 105 years, … Continue reading

Posted in Paleoclimatology | Tagged , , , | 60 Comments

Tree rings as a proxy for historical ENSO reconstruction

From the University of Hawai’i’s International Pacific Research Center at Mānoa, comes this proxy reconstruction that does some similar things the infamous hockey stick reconstruction, but doesn’t need to pull any statistical “tricks” to make the case. Our old friend … Continue reading

Posted in Uncategorized | Tagged , , , , , | 120 Comments

Climate Bloodhounds

Steve McIntyre is blogging again. This time it is about a little noticed Climategate email where Dr. Raymond Bradley disses skeptics as being too unsophisticated to be able to figure out what was withheld. I agree with Steve, when he … Continue reading

Posted in Paleoclimatology | Tagged , , | 103 Comments