Tag Archives: pages2k

Millennial Quebec Tree Rings

In today’s post, I’m going to discuss an important new 1000-year chronology from northern treeline spruce in Quebec (Gennaretti et al 2014, PNAS here).  The chronology is interesting on multiple counts.  This is the first Quebec northern treeline chronology to include the medieval warm period.  Second, it provides a long overdue crosscheck against the Jacoby-D’Arrigo chronologies (including […]

New Article on Igaliku

Shortly after the publication of PAGES2K, I pointed out that the Igaliku lake sediment proxy, had been contaminated by modern agricultural runoff. The post attracted many comments. Nick Stokes vigorously opposed the surmise that the Igaliku series had been contaminated by modern agriculture and/or that such contamination should have been taken into account by Kaufman […]

PAGES2K vs the Hanhijarvi Reconstruction

The PAGES2K (2013) Arctic reconstruction of Kaufman et al has attracted considerable attention as a non-Mannian hockey stick. However, it’s been fraught with problems since day one, including a major re-statement of results in August 2014 (McKay and Kaufman, 2014 pdf), in which Kaufman conceded (without direct acknowledgement) Climate Audit criticism that their results had been […]

Okshola: which way is up?

The recent revisions to PAGES2K included a dramatic flipping of the Hvitarvatn varve series to the opposite orientation used in the 2013 version used in IPCC AR5. Together with other changes (such as a partial – but still incomplete – removal of contaminated sediments from the Igaliku series), this unwound most of the previous difference […]

Revisions to Pages2K Arctic

Kaufman and the PAGES2K Arctic2K group recently published a series of major corrections to their database, some of which directly respond to Climate Audit criticism. The resulting reconstruction has been substantially revised with substantially increased medieval warmth. His correction of the contaminated Igaliku series is unfortunately incomplete and other defects remain.

A New Alaskan d18O Series

PAGES2K Arctic introduced a lake sediment d18O series from Kepler Lake, Alaska that hadn’t been used in previous studies. Although O18 data is a workhorse of paleoclimate, O18 data from Alaska (or, for that matter, anywhere in the Arctic hemisphere between 90E and 90W – going east) is very scarce. Thus, the appearance of a […]

Varved Inconsistency

Since AR4, there have been a series of new multiproxy studies, several of which were cited in AR5 (Mann et al 2008; Ljungqvist et al 2010; Christiansen and Ljungqvist 2012; Shi et al 2013). A distinctive feature of these and other recent multiproxy studies is the incorporation of varve thickness and near-equivalent mass accumulation rate […]

More on Hvitarvatn Varves

In a previous post on PAGES2K Arctic, I pointed out that they had used the Hvitarvatn, Iceland series (PAGES2K version shown below), upside-down to the interpretation of the original authors (Miller et al), who had interpreted thick varves as evidence of the Little Ice Age. A few days ago, Miller and coauthors archived a variety […]

PAGES2K Online “Journal Club”

I’m listening to a presentation by PAGES2K authors sponsored by Nature: http://blogs.nature.com/ofschemesandmemes/2013/05/02/npg-journal-club-how-has-earths-climate-changed-in-the-past-2000-years-npgjclub#comment-1503 Started at 11 am Eastern. 11:30. Open for questions. I have submitted the following: Can you explain the decision to label the article as only a “Progress Article”, rather than a Research Article? Nature’s definition of Progress Articles http://www.nature.com/ngeo/authors/content_types.html says that such articles […]

More Kaufman Contamination

Kaufman and paleo peer reviewers ought to be aware that the recent portion of varve data can be contaminated by modern agriculture, as this was a contentious issue in relation to Mann et al 2008 (Upside Down Mann) and Kaufman et al 2009. Nonetheless, Kaufman et al 2013 (PAGES), despite dozens of coauthors and peer […]

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