Category Archives: Proxies

Mann on Irreproducible Results in Thompson (PNAS 2006)

Michael Mann’s new book, The Hockey Stick and the Climate Wars, discusses my comment [SMc note – this post is by Hu McCulloch] , “Irreproducible Results in Thompson et al., ‘Abrupt Tropical Climate Change: Past and Present’ (PNAS 2006),” that was published in 2009 in Energy & Environment. My comment pertained to an article by […]

Kinnard Arctic O18 Series

Kinnard et al 2011 report a highly hockey-stick shaped reconstruction of sea ice. (For a different perspective based on Holocene ocean sediments under the Ellesmere Island ice shelf, see the recent Antoniades et al (PNAS 2011). Kinnard et al use a regression-based statistical methodology that looks at first blush to be a sort of inverse […]

Krummholz and the Yamal Chronology

Just before Climategate, we were reflecting on the apparent non-“robustness” of the Yamal chronology to inclusion of Khadyta data. Briffa’s response was that he could still “get” a HS by adding in Yadoyayakha and Porzayakha ring width data that hadn’t been used in Briffa (2000). As noted in other posts, Khadyta isn’t the only site […]

Yamal Aerial Photo

Here’s a Gazprom aerial photo which illustrates this better than 1000 words. (Yamal is the location of some huge Gazprom natural gas fields.) From the colors, I presume that the picture is taken in fall as the larch have changed color. Spruce do not appear to be in evidence here – they have a more […]

Yamal and the Decline

Contrary to a myth believed in by the climate science “community”, most recent multiproxy reconstructions are not “independent” – they merely recycle the same stereotypes with slightly different weighting methods. In an email (1140039406.txt) in which Briffa urges Overpeck not not to “over egg the pudding”, he stated: “Peck, you have to consider that since […]

Say My Name – February Rerun

Science has published a Correction and Clarification to Kaufman et al (2009), see here. Since they only needed to correct four out of 23 proxies, there is no need to name those who pointed out errors. ;) There is a small improvement over the draft version though; congratulations Hu! We thank H. McCulloch and others […]

The Hockey Stick and the Milankovitch Theory

The 20th century warming counters a millennial-scale cooling trend which is consistent with long-term astronomical forcing. MBH99 According to the UMass researchers, the 1,000-year reconstruction reveals that temperatures dropped an average of 0.02 degrees Celsius per century prior to the 20th century. This trend is consistent with the “astronomical theory” of climate change, which considers […]

What Happened to Polar Urals?

Addiction of paleoclimate reconstructions to particular proxies has been a longstanding concern at Climate Audit. One of the battleground issues has been the addiction to Briffa’s Yamal tree ring series, while the nearby update of Polar Urals (with a pronounced MWP) was disappeared. (See CA category.) Just before Climategate, we raised questions about the Yamal […]

Difference in Yamal Versions “Not Insignificant”

In July 2003, Tim Osborn advised Tom Crowley that there were multiple versions of Yamal (and Tornetrask) and that he needed to contact Briffa prior to using: The other files are “tornad.rcs” and “yamal.rcs” which are RCS-standardised tree-ring width series. I would really strongly suggest that you contact Keith Briffa about exactly what these series […]

Calibrating “Dr. Thompson’s Thermometer”

One of the most persuasive images in the global warming debate is a graph that Al Gore describes in his An Inconvenient Truth as “Dr. Thompson’s thermometer.” According to Gore, this graph is based on oxygen isotope ratios from ice cores collected by Lonnie Thompson and his colleagues, and provides “the most definitive” independent confirmation […]


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