Category Archives: General

Spot the Hockey Stick #n+…

The UNEP CLIMATE CHANGE SCIENCE COMPENDIUM 2009 on page 5 uses the following graph from Wikipedia (not the IPCC Fourth Assessment Report): CO2 concentration and mean global temperature during the past millennium. CO2 levels (blue line, lefthand axis) are given in parts per million, temperatures (red line, right-hand axis) in degrees Celsius. Source: Hanno 2009 […]

Loso: Varve Thickness and Nearest Inlet

One excellent feature of the Alaskan varvochronologists is that (unlike, say, Bradley and his coterie) some of them show and archive their work. The Kaufman student MSc theses are good at this. So too is Michael Loso’s work on Iceberg Lake. Thus while one can raise an eyebrow at (and criticize) their statistical peregrinations, at […]

Varves: To Log or Not to Log

The majority of Kaufman’s varvochronology proxies are various functions of varve thickness – which, if anything, seem more problematic than sediment BSi. While Kaufman’s offering memorandum to NSF promised consistency, the handling of varve thicknesses in the various selections seems to be anything but. Kaufman et al 2009 gives no hint of the varied functional […]

Overpeck’s Enigmatic Tuq(?)

In fairness to Kaufman, he and his students actually did useful field work. Elsewhere I’ve noted that their MSc theses contain many helpful details on the Alaskan lakes. The situation is entirely different with the Greenland lakes, where Jonathan Overpeck was the point man for the ARCUS2k lake project collection. Kaufman et al 2009 contains […]

Kaufman's "Classical" Log Regression

I observed yesterday that I had been unable to replicate the archived version of Kaufman’s Hallet Lake series – something that I thought was due to a change in the archived version (since the NCDC archive noted that a new version had been archived in Nov 2008.) This turns out not to be what happened. […]

Five Alaskan BSi Series

At the second meeting of Kaufman’s PIs, one of the scientists plaintively asked: But shouldn’t we aim to do a synthesis that is only lake seds (at least as first step)? This logical building block was pushed aside (thereby allowing Briffa’s Yamal series to be recycled for the nth time) on the following grounds: some […]

Kaufman's BSi Selection

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 […]

Invalid Calibration in Kaufman 2009

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 […]

Kaufman's Stick: Iceberg Lake Varves

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 […]

Sea Ice – Sept 2009

Continued from here . On August 19, 2009, NSIDC published the following August forecast of sea ice minimums by the leading climate modelers around the world. The majority of modelers predicted that 2009 sea ice minimums would be below 2008 and one (Arbetter et al) even predicted that 2009 would break the 2007 record. The […]

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