Blog Links: Mann '08 and the Korttajarvi (Tiljander) Varve Proxies

Compilation of links to blog posts and comments that address the controversy surrounding Mann et al (2008)'s use of the lakebed sediment record from Lake Korttajarvi, Finland in their reconstructions of global climate, 200 AD to 1850.

See also Primary Links: Mann '08 and the Korttajarvi (Tiljander) Varve Proxies


Please add missing URLs in the comments. Since it's a compilation with little editorial content, this post may be updated without notice.

ClimateAudit.org ("skeptical" perspective)

Mann et al 2008: Korttajärvi, Steve McIntyre, Sept. 3, 2008. The first claim that Mann et al used certain proxies in an upside-down orientation. Note Comment #9 by "varve".

Mann et al 2008 and GAAP Accounting, Steve McIntyre, Oct. 1, 2008. Uses an accounting analogy to describe the handling of the Upside-Down Lake Korttajarvi proxies.

It's Saturday Night Live, Steve McIntyre, Oct. 2, 2008. Detailed, illustrated explanation of the Upside-Down use of Lake Korttajarvi proxies. Comment #74 includes graphs of all four Lake Korttajarvi proxies.

Can't See the Signal For the Trees, Willis Eschenbach, Nov. 23, 2008. Explains a straightforward statistical technique for combining proxies. Concludes that the longer term proxies in Mann et al (2008) are totally dominated by the Tiljander and the 19 southwestern US "stripbark" pine proxies. These proxies create the Hockeystick shape found in the signal.

All-Proxy CPS, Steve McIntyre, Dec. 3, 2008. Emulation of Mann et al's CPS algorithm.

More Upside-Down Mann, Steve McIntyre, Apr. 15, 2009 [URL fixed 27 June 2010] Identification of Speleo SU-967 as another proxy used in an inverted orientation in the Mann et al. (2008) paleotemperature reconstructions.

Upside-Side Down Mann and the "peerreviewedliterature", Steve McIntyre, Oct. 14, 2009. Good thread.

Connolley Endorses Upside Down Mann, Steve McIntyre, Oct. 29, 2009. Good thread.

Another Correction from Upside Down Mann, Steve McIntyre, Nov. 7, 2009

The No-Dendro Illusion, Steve McIntyre, Aug. 1, 2010. [Added to list on 2 Aug. 2010.] Discussion of in-line comments by Gavin Schmidt (in "The Montford Delusion" RealClimate thread) on the effects of using the Tiljander proxies in the paleoclimate reconstructions of Mann08 (PNAS) and Mann09 (Science). Dr. Schmidt indicated en passant that inclusion of the Tiljander proxies does matter, greatly increasing the time periods during which certain reconstructions "pass validation." That the use of the Tiljander proxies "doesn't matter" had been key to the defense of Mann08 by AGW Consensus scientists and advocates.

AMac: Upside Down Mann Lives on in Kemp et al 2011, Steve McIntyre, June 21, 2011. [Added to list on 14 Aug. 2011.]

Dirty Laundry II: Contaminated Sediments, Steve McIntyre, July 6, 2011. [Added to list on 14 Aug. 2011.] Extensive post on the effect of inclusion of the Tiljander data series on the paleotemperature reconstructions offered in Mann08.

RealClimate.org ("mainstream" climate-science perspective)

Progress in reconstructing climate in recent millennia, Gavin Schmidt, Sept. 3, 2008. [Added to list on 7 Mar. 2010] Opening-day review of Mann et al. (2008). A good summary of what Prof. Mann's group was aspiring to accomplish. No mention of the Lake Korttajarvi proxies in the post; the issue arises in Comment #51 (where Dr. Schmidt dismisses their importance) and Comment 54.

RealClimate.org - Hey Ya! (mal), Group authorship, Sept. 30, 2009. Brief discussion in the Comments at #651, #665, and #673. [Remarks on Comments added 27 Jun. 2010]

RealClimate.org - Comments on the CRU Hack: Context, Comment #132, Gavin Schmidt, Nov. 23, 2009. Dr. Schmidt's defense of Mann et al's handling of the Lake Korttajarvi proxies.

The Montford Delusion, Tamino, July 22, 2010. [Added to list on 2 Aug. 2010] Tamino's post does not discuss the Tiljander proxies. However, the subject is broached in the lengthy comment thread, and discussed by Gavin Schmidt. His in-line commentaries are at comments 171 (D. Robinson), 414 (Judith Curry), 483 (Bernie), 525 (pjclarke), 529 (Nicholas Nierenberg), and 531 (Nicholas Nierenberg). Dr. Schmidt offers important insights into the effects of using the Tiljander proxies in the paleoclimate reconstructions of Mann08 (PNAS) and Mann09 (Science), discussed at the ClimateAudit post The No-Dendro Illusion.

2000 Years of Sea Level (+updates), Stefan Rahmstorf, 20 June 2011. [Added to list on 14 Aug. 2011.]

Stoat ("mainstream" climate-science perspective)

Stoat - Oh dear oh dear oh dear oh dear, WM Connolley, Oct. 27, 2009. Annotated version of comment thread elsewhere on this blog. [Remarks added 27 Jun. 2010]

Stoat - Tiljander, WM Connolley, Oct. 29, 2009. Good thread

Stoat - Tiljander, again, WM Connolley, Nov. 4, 2009. Good thread.

the Air Vent ("skeptical" perspective)

How to Make a Hockey Stick – Paleoclimatology (What they don’t want you to know), Jeff Id, Sept. 4, 2008. Discussion of generation of spurious signals by noisy proxies.

Mann 08 Temperature Reconstruction Using Less Than 11% of the Data, Jeff Id, Sept. 27, 2008. Reconstruction of temperature anomaly curve of Mann et al (2008).

Mann 08 Series Weight Per Year, Jeff Id, Sept. 28, 2008. Reconstruction of Mann et al (2008) temperature anomaly graph, showing estimated weighting of Lake Korttajarvi (and other) proxies.

Mannian Science, Jeff Id, June 10, 2009. Discussion of Upside-Down orientation of temperature proxies.

Who's In Denial, Jeff Id, Nov. 5, 2009.

Mann09 Analog vs Digital, Jeff Id, Nov. 28, 2009. Discussion of weighting of proxies in temperature anomaly graphs of Mann et al (Science 2009). Note Comment #15 on the uninformative nature of including/excluding the Lake Korttajarvi proxies from Mann et al (2008) Fig. S8a.

Roger Pielke Jr. ("mainstream" climate-science perspective)

A Point Resolved in the Hockey Stick Wars, Oct. 26, 2009.

Will William Connolley do the Right Thing?, Oct. 29, 2009.

Cruel Mistress ("mainstream" climate-science perspective)

Peer Review. Game on. Ben Hale, Oct. 26, 2009

More Grumbine Science ("mainstream" climate-science perspective)

Sound and Fury at WUWT Bob Grumbine, Oct. 19, 2009. Non-technically-informed defense of Mann et al's methods.

Watts Up With That? ("skeptical" perspective)

IQ Test: Which of these is not upside down? Antony Watts, Oct. 17, 2009

Climate Progress ("mainstream" climate-science perspective)

Sorry deniers, hockey stick gets longer, stronger: Earth hotter now than in past 2,000 years, Joe Romm, Sept. 3, 2008. [Added to list on 7 Mar. 2010] Favorable opening-day review of Mann et al. (2008) ("...I suspect this will be a definitive work for quite some time"). No mention of possible problems with Lake Korttajarvi proxies in post or comments.

Delayed Oscillator ("mainstream" climate-science perspective)

Talk about Tiljander Delayed Oscillator, Nov. 3, 2009. Favorable comment on Stoat's discussion of Mann et al's methods.

AGW Observer ("mainstream" climate-science perspective)

Papers on reconstructions of modern temperatures. Ari Jokimäki, Nov. 17, 2009. Compilation of papers in the same general subject area as Mann et al.

Climate Observations ("skeptical" perspective)

A Look At The Individual Proxies Used In Kaufman et al (2009). Bob Tisdale, Dec. 17, 2009. Graphical depictions of proxies used by Kaufman, including Tiljander XRD through 1800 (and multiple additional varve series).

Climate Skeptic ("skeptical" perspective)

Regression Abuse. Warren Meyer, Oct. 29, 2009. [Added to list on 28 Feb. 2010] Discussion of how the Mann et al (2008) calibration strategy led to the inverted use of the Tiljander XRD proxy.

Collide-a-scape ("mainstream" climate-science perspective)

The Main Hindrance to Dialogue (and Detente). Keith Kloor, Jun. 16, 2010. [Added to list on 27 Jun. 2010] Climate scientist and RealClimate.org blogger Gavin Schmidt identifies my comments on blogs (like this one [link updated 8/2/10]) as an example of a major pathology that prevents climate scientists from undertaking dialogue with critics. My responses are in the comment thread; the final one is #132 [8/2/10, now #146].

Not Spaghetti ("mainstream" climate-science perspective)

The post Steven Mosher: even Fuller of it (Jun. 18, 2010) was blogger Arther Smith's criticism of author Steven Mosher's analysis of the truncation of the "Briffa reconstruction" in a figure in Chapter 6 of the IPCC AR4 report (Mosher acknowledged making the error Smith asserted). In the ensuing thread, Smith brings up possible teachings from other allegations of errors by AGW Consensus scientists. My comment Tiljander/Mann fraud? (06/27/2010 - 11:35) outlines my current view of the meaning and context of discussed the Tiljander/Mann08 case. Arthur Smith elevated it to the body of his next post (below). [Added to list on 27 Jun. 2010; revised 7 July 2010]

Where's the fraud?. Arthur Smith, June 27, 2010. [Added to list on 7 July 2010] Arthur Smith reviews the AGW Consensus stance on the use of the Tiljander proxies (and other issues with Mann08), Part 1. Good discussion in the comments.

Michael Mann's errors. Arthur Smith, June 30, 2010. [Added to list on 7 July 2010] Arthur Smith reviews the AGW Consensus stance on the use of the Tiljander proxies (and other issues with Mann08), Part 2. Good discussion in the comments.

AGW Observer ("mainstream" climate-science perspective)

Tiljander. Ari Jokimäki, June 28, 2010. [Added to list on 7 July 2010] Ari Jokimäki considers revising his support of the AGW Consensus stance on the X-Ray Density proxy, first outlined in the comments at Stoat. Good discussion in the comments.

Our Changing Climate ("mainstream" climate-science perspective)

How science does and does not work (and how skeptics mostly fall in the latter category). Bart Verheggen, June 22, 2011. [Added to list on 14 August 2011.] The Tiljander data series are first mentioned in this comment by MikeN. Involved discussions of the subject follow.