Below is a plot comparing sediment BSi (biological silica) to depth (cm) from two of Kaufman’s lakes (done by different students). I’ve shown it by depth (rather than ascribed age) since the dating of these sediment series is not without some hairiness. I’ve shown equal lengths for each lake, both covering at least 800AD-present on […]
A common meme in Team-world these days is that any issues or errors are minor and that none of them “matter”. As we peel back the layers of Kaufman et al, this is the first line of Team defence. The rhetorical impact of Team reconstructions largely derives from the modern-medieval differential: is it in the […]
Darrell S. Kaufman, David P. Schneider, Nicholas P. McKay, Caspar M. Ammann, Raymond S. Bradley, Keith R. Briffa, Gifford H. Miller, Bette L. Otto-Bliesner, Jonthan T. Overpeck, and Bo M. Vinther (Science 9/4/2009) propose a reconstruction of Arctic summer land temperatures for the last 2000 years, using 23 diverse proxies. Decadal averages of each proxy […]
The backstory to the development of the Kaufman et al 2009 reconstruction is pretty interesting. A few years ago (after the MM criticisms of paleoclimate reconstructions), the US National Science Foundation sponsored the sampling of 30 Arctic lakes in a standardized way. It’s remarkable to compare the original population to the data sets used in […]
A CA reader sent me an email, noting the following entry in minutes of a meeting. M Loso inquired about Lonnie Thompson’s ice core data. These data are not presently available but will be investigated by Caspar. This comment is minuted in a meeting of PIs leading up to Kaufman et al 2009 – a […]
In the first post on Kaufman et al, I observed that, like other Team multiproxy studies, its HS-ness is contributed by only a few series. As shown below, a composite of 19 out of 23 Kaufman proxies does not yield an “unprecedented” late 20th century (tho it yields an elevated late 20th century.) A composite […]
Kaufman et al (2009), published at 2 pm today, is a multiproxy study involving the following regular Team authors: Bradley, Briffa (the AR4 millennial reconstruction lead author), Overpeck, Caspar Ammann, David Schneider (of Steig et al 2009), Bradley as well as Otto-Bleisner (Ammann’s supervisor and conflicted NAS Panel member) and “JOPL-SI authors” who are various […]
The 2009 Climate Dynamics paper “Unprecedented low twentieth century winter sea ice extent in the Western Nordic Seas since A.D. 1200” by M. Macias Fauria, A. Grinsted, et al. discussed already on the thread Svalbard’s Lost Decades pre-smooths its data with a 5-year cubic spline before running its regressions. There’s been a lot of discussion […]
Trouet et 2009 posit a positive NAO as the “explanation” of the Medieval Climate Anomaly, pausing only briefly to ask what might have caused a centuries long (“temporally pervasive”) positive NAO, falling back on an arm-waving attribution to a stronger Atlantic meridional overturning circulation: The persistently strong winter MCA NAO and its weakening during the […]
Previously, we discussed the upside-down Tiljander proxies in Mann et al 2008. Ross and I pointed this out in our PNAS comment, with Mann denying in his answer that they were upside down. This reply is untrue (as Jean S and UC also confirmed.) Andy Baker’s SU967 proxy is used in Mann 2008 and is […]
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