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’] in the final chronology.” Basically, older trees grow slower, and that mimics the temperature signal…

Advertisements

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

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 of Dr. Mann’s effort – and it appears there is a rift now between former…

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 graph 5c, and you’ll see 20th century warmth matches peaks either side of the year…

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 what he and Dr. Trenberth’s government funded advocacy looks like. I can’t wait to see…

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 Volcanism and the Atmosphere in Selfoss, Iceland 10–15 June 2012 tells the story: And Witze…

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 to note that he reports that the blogosphere is becoming increasingly important as a tool…

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 (here, leading to embellishment across parts of the blogosphere, e.g. here) that the Climatic Research…