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

I'm compiling links to webpages 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 Blog 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.

The Lake Korttajarvi Borehole

Google Maps view of Lake Korttajarvi borehole at Lat 62.3318, Long 25.6821

Finnish-language map of Lake Korttajarvi

Mia Tiljander, M Saarnisto, AEK Ojala, and T Saarinen. "A 3000-year palaeoenvironmental record from annually laminated sediment of Lake Korttajarvi, central Finland." Boreas 26:566–577, 2003. [Update 14 March 2010: PDF archived at ClimateAudit.info (not ClimateAudit.org). Abstract at the Wiley website.]

Mia Tiljander. "Holocene sedimentary history of annual laminations of Lake Korttajärvi, central Finland." PhD Dissertation, University of Helsinki, Dept. of Geology, Geology and Palaeontology. October 2005. Archived PDF. Includes the quote, "Since the early 18th century, the sedimentation has clearly been affected by increased human impact and therefore not useful for paleoclimate research." (pg. 24).

Lake Korttajärvi, Finland 2000 Year Varved Sediment Data, NOAA text-file FTP archive, updated Sept. 2009. "Mineral", "Organic", and "X-Ray Density" values, 0 - 1985. [UPDATE 8/16/11 -- for the year 1326, values for Lightsum and Darksum (and thus Thickness, as well) are anomalous, over tenfold higher than any neighboring year. Somehow, in the files archived at the Mann website, these numbers have been overwritten by the average of the values for 1325 and 1327.]

NOAA text-file data in ".csv" format, uploaded Nov. 2009 to BitBucket.org

AMac's downloadable files at BitBucket.org. See the directory's summary.


The Mann et al (2008) PNAS paper, Supporting Information, Comments, and Data Archives

Michael E Mann, Zhihua Zhang, Malcolm K Hughes, Raymond S Bradley, Sonya K Miller, Scott Rutherford, & Fenbiao Ni. "Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia." PNAS 105:13252–13257, Sept. 9, 2008. Published online Sept. 2, 2008. Received for review Nov. 20, 2007. Communicated by LG Thompson, OSU. PNAS web page with full text as HTML and PDF, Supporting Information as PDF

S McIntyre & R McKitrick. "Proxy inconsistency and other problems in millennial paleoclimate reconstructions." PNAS 2009 106:E10, online publication 2 Feb. 2009. PNAS web page with full text as HTML and PDF

ME Mann, RS Bradley, & MK Hughes.  "Reply to McIntyre and McKitrick: Proxy-based temperature reconstructions are robust." PNAS 2009 106:E11, online publication 2 Feb. 2009. PNAS web page with full text as HTML and PDF

Prof. Mann's main Penn State University page

Mann's Penn State page for Mann et al (2008) Supplemental Information and Data, updated Nov. 4, 2009

Downloadable data set for Mann et al (2008), hosted at NOAA. Includes Lake Korttajarvi primary data in file proxy-original.zip as text files tiljander_2003_darksum.ppd, tiljander_2003_lightsum.ppd, tiljander_2003_thicknessmm.ppd, and tiljander_2003_xraydenseave.ppd. Last updated Sept. 30, 2008 11:08:20 EDT

Graphic representations of the >1000 proxies used by Mann et al 9208), hosted at ClimateAudit.org and expressed in terms of standard deviations vs. time. Directory last updated Sept. 27, 2008. Images include proxy1061.gif (tiljander_2003_darksum), proxy1062.gif (tiljander_2003_lightsum), proxy1063.gif (tiljander_2003_thicknessmm), and proxy1064.gif (tiljander_2003_xraydenseave).

Mann et al (2008) Fig. S8a Once-Corrected Version, PDF, downloaded circa 3 Nov. 2009, from the Mann group's 'Meteo' webpage; release notes. [revised 9 March 2010]

Mann et al (2008) Fig. S8a Twice-Corrected Version, PDF, downloaded circa 5 Nov. 2009 from the Mann group's webpage; release notes. [revised 9 March 2010]

PNAS Information for Authors -- (viii) Materials and Data Availability. "To allow others to replicate and build on work published in PNAS, authors must make materials, data, and associated protocols available to readers. Authors must disclose upon submission of the manuscript any restrictions on the availability of materials or information."


The Kaufman et al (2009) Science paper and Supporting Information

DS Kaufman, DP Schneider, NP McKay, CM Ammann, RS Bradley, KR Briffa, GH Miller, BL Otto-Bliesner, JT Overpeck, BM Vinther, & Arctic Lakes 2k Project Members. "Recent Warming Reverses Long-Term Arctic Cooling." Science 325:1236-1239, 2009. Science web page for Abstract and Supporting Online Material, registration required for full text


The Mann et al (2009) Science paper, Supporting Information, Comments, and Data Archive

ME Mann, Z Zhang, S Rutherford, RS Bradley, MK Hughes, D Shindell, C Ammann, G Faluvegi, and F Ni. "Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly." Science 326:1256-1260, 2009. Science web page for Abstract and Supporting Online Material, registration required for full text


Hacked "Climategate" Emails Relevant to the use of the Lake Korttajarvi Proxies in Mann et al (2008)

East Anglia Email 1252164302.txt (also 1252154659.txt and 1252154659.txt). Emails sent by Nick McKay on 3 Sep. 2009 and 4 Sep 2009; responses from Darrell Kaufman and Jonathan Overpeck on 5 Sep. 2009. McKay, Kaufman, and Overpeck recognized that certain Lake Korttajarvi proxies were used upside-down in the initial published draft of Kaufman et al. (2009) (and therefore in Mann et al. (2008)). Describes process of correcting final version of paper, initiated after reading McIntyre's critiques. [Entry added 27 Jun 2010]


Analysis of Sediments from Other Scandanavian Lakes

Antti E.K. Ojala, "Varved Lake Sediments in Southern and Central Finland: Long Varve Chronologies as a Basis for Holocene Palaeoenvironmental Reconstructions." Academic Dissertation, Geological Survey of Finland, Espoo 2001. 41 pages. PDF archived at the Geological Survey of Finland (GTK). Describes the collection and analysis of varved sediments at Lake Nautajärvi and Lake Valkiajärvi, with references made to four other Finnish lakes: Lake Korttajärvi, Lake Alimmainen Savijärvi, Lake Kortejärvi, and Lake Lehmilampi. AEK Ojala is the third author of Tiljander03. [Added 8/3/10, hat tip to Jarmo]. From page 31:

...the recent agricultural activity [near Lake Nautajärvi] has obscured the natural signals of physical varve data, as shown by several authors earlier ([references]). According to Saarnisto (1986), small lakes respond to rapid environmental changes faster, but are more easily affected by local disturbances. Therefore, the calibration of the physical varve-data against instrumental records is, in many cases, very difficult if not impossible. The importance of multidisciplinary studies ([references]) needs to be emphasized again, because it provides a better estimate of the timing and magnitude of the effects of these cultural-related activities effect on lake sedimentation. A palaeoecological study of Lake Korttajärvi (Tiljander & Saarnisto, [MS in preparation]), for example, reported that an intensive cultivation in the vicinity of Korttajärvi began in the 16th century [sic--Tiljander03 states "around 1720"--AMac], as indicated by the typical culture-related pollen assemblages, L.O.I. and charcoal stratigraphy. Prior to that, fluctuations in varve composition and structure more likely reflect signals of natural origin.

M Tiljander, JA Karhu, & T Kauppila. "Holocene records of carbon and hydrogen isotope ratios of organic matter in annually laminated sediments of Lake Korttajarvi, central Finland." Journal of Paleolimnology 36: 233-243, 2006. Abstract (text behind paywall). A study of δ13C and deuterium (δD) isotopes in organic matter from 2o sediment cores retrieved from Lake Korttajarvi. The authors write that "the Medieval Warm Period (AD 980-1250) is associated with a local maximum in δD, lending support for a significant warming during that time" (figure).

Eeva Haltia-Hovi, Timo Saarinen, & Maaret Kukkonen. "A 2000-year record of solar forcing on varved lake sediment in eastern Finland." Quaternary Science Reviews 26: 678-689, 2007. PDF.

Tomi P. Luoto, "Spatial and temporal variability in midge (Nematocera) assemblages in shallow Finnish lakes (60−70 °N): community-based modelling of past environmental change." Academic dissertation, Helsinki University, 2010. 62 pages. PDF archived at the University of Helsinki. Describes analysis of fossil midges and other indicators of past climate conditions in Lake Pieni-Kauro (with some analysis and discussion of other Finnish lakes and rivers). [Added 8/4/10, hat tip to Jarkko].

Mia Tiljander, Antti E.K. Ojalaa, Timo Saarinena & Ian Snowball, "Documentation of the physical properties of annually laminated (varved) sediments at a sub-annual to decadal resolution for environmental interpretation." Quaternary International 88: 5-12, 2002. Abstract. [Added 8/14/11.]

Antti E.K. Ojala & Mia Tiljander, "Testing the fidelity of sediment chronology: comparison of varve and paleomagnetic results from Holocene lake sediments from central Finland." Quaternary Science Reviews 22: 1787-1803, 2003. Abstract. [Added 8/14/11.]


Other Analyses of Varved Lakebed Sediments

A Brauer, GH Haug, P Dulski, DM Sigman, & JFW Negendank. "An abrupt wind shift in western Europe at the onset of the Younger Dryas cold period." Nature Geoscience 1: 520-523, 2008. PDF. [Added 8/25/10, hat tip to Hank Roberts]. The varved sediments of Lake Meerfelder Maar contain a clear record of the transition of the Holocene climate to the colder Younger Dryas regime, 12,700 BP.

EK Thomas, J Szymanski, & JP Briner. "Holocene alpine glaciation inferred from lacustrine sediments on northeastern Baffin Island, Arctic Canada." J. Quaternary Sci. 25: 146–161, 2010. PDF. [Added 8/25/10, hat tip to Shirley Pulawski]. In this glacial setting, accurate and precise dating of varves isn't possible. Useful demonstration of climate-proxy information at coarser time scale, throughout the Holocene.

P.E. O'Sullivan, "Annually-laminated lake sediments and the study of Quaternary environmental changes — a review." Quaternary Science Reviews 1: 245-313, 1983. Abstract. [Added 8/14/11.]

Scott Lamoureux, "Varve Chronology Techniques." Chapter 11 of Developments in Paleoenvironmental Research, 2002, Volume 1, Part III W.E. Last & J.P. Smol, eds. Springer, 2002, pgs 247-260. Abstract and Google Books excerpt. Discussion of core-preparation techniques, with examples from Lake Korttajarvi and other Finnish lakes. Describes typical "drift" of if imputed date away from actual date in varve counts from single cores.[Added 8/17/11.]