In today’s post, I’ll return to more typical Climate Audit programming. Upside-down Mann’s mentor, Raymond Bradley, has somewhat surprisingly published an article (Balascio et al 2015) that supports a longstanding Climate Audit criticism of varve proxies. Bradley and coauthors did not report that their interpretation of an important Baffin Island series is upside-down to the orientation used in PAGES2K and numerous AR5 vintage multiproxy reconstructions. It seems that proxies used by the Team are like the Grand Old Duke of York:
And when they were up, they were up,
And when they were down, they were down,
And when they were only half-way up,
They were neither up nor down.
Background
Ever since Mann et al 2008 and Kaufman et al 2009, varve thickness (and similar series) from Arctic lakes have become a staple of multiproxy reconstructions purporting to yield hockey sticks, including PAGES2K and most other AR5 reconstructions. Several varve series are used over-and-over in multiple supposedly “independent” studies, one of which is the Big Round Lake varve series from Baffin Island (Thomas and Briner 2009). The assumption in the varve series used in reconstructions, including PAGES2k (2013) has been that thick varves indicate warm temperatures. I’ve written many critical posts on these supposed “proxies”, beginning, of course, with criticism of Upside Down Mann’s upside down use of the contaminated modern portion of the Tiljander sediment data from Finland (impacted by agricultural runoff). Mann has unrepentantly continued to use this contaminated data, most recently to “reconstruct” ocean currents in the Atlantic. I’ve also written many critical posts on varve series.
A couple of years ago, I noticed that Gifford Miller had interpreted thick varves at a proglacial lake (Hvitarvatn) in Iceland as evidence of expanded glacier activity – an interpretation made particularly convincing by the association of ice-rafted debris in the LIA with thick varves. At the time, I observed that the Big Round Lake (Baffin Island) varve series was closely related to the Hvitarvatn series and that it was implausible to give opposite orientations to two such similar series. The PAGES2K Arctic reconstruction placed the matter at issue once again, since it used varve series from both Hvitarvatn and Big Round Lake, orienting each series so that thick varves were interpreted as “warm” and thin varves as “cold”. The PAGES2K orientation was opposite to that published by Miller et al and, taken literally, implied that Iceland had a Medieval Cold Period followed by a Little Warm Age in the 17-19th centuries. In my original review of PAGES2K, I pointed out the inconsistency between the original Miller et al interpretation and the PAGES2K orientation.
Last year, following a dubious practice pioneered by Mann, two PAGES2K authors (Kaufman and McKay) published an article in a different journal which conceded errors in the original Arctic2K reconstruction, while refusing to publish a corrigendum to the original article. One of their admissions was that they had used the Hvitarvatn series upside down. When the reconstruction was re-calculated with Hvitarvatn in the opposite orientation, there was a major impact on the Arctic reconstruction, undermining some of the headline assertions about 20th century uniqueness. (I formally asked Nature to require PAGES2K to publish a corrigendum, but they refused.)
In my review of McKay and Kaufman 2014, I pointed out that PAGES2K now had opposite orientations for the Hvitarvatn (Iceland) and Big Round Lake (Baffin Island) series, even though the series were very similar in appearance and clearly required consistent interpretation. I argued as follows (not that I expected Kaufman to concede the point) :
This confirmation of my interpretation is of considerable interest to me, since there seems to be a close relationship between the Iceland varve series and Baffin Island varve series, a location of considerable interest from a multiproxy perspective, as discussed in a previous post here, where I showed the close relationship between the Hvitarvatn, Iceland varve thickness series and the Big Round Lake, Baffin Island varve thickness as below. PAGES2K is in the awkward position of orienting the Hvitarvatn in an opposite orientation to their orientation of Big Round Lake, though the two series are evidently responding similarly. It is surely unacceptable for assessment-quality studies to leave such inconsistencies unresolved.
I also observed that inversion of the Big Round Lake series to match the Hvitarvatn would invert the series in numerous AR5 reconstructions.
Balascio et al 2015
Balascio et al 2015, of which Bradley is a coauthor, is an interesting technical study of a proglacial lake in Greenland (Lake Kulusuk). Similarly to the interpretation of other proglacial lakes, they interpreted high mineral content in the sediments as evidence of glacier advance and high organic content as evidence of glacial recession. At Lake Kulusuk, they (plausibly) interpreted the low magnetic susceptibility and high organic content in the Holocene Optimum (HTM – yellow) as evidence of glacier recession. They also carried out a high-resolution xray fluorescence analysis (XRF) and found that the mineral suite was highly correlated to magnetic/organic content, as clearly seen by its PC1, which had a very distinct Holocene Optimum as shown in their figure excerpted below:
Figure 1. From Balascio et al 2015.
Balascio et al directly compared the data from their proglacial lake in Greenland to the proglacial lakes in Iceland (Hvitarvatn) and Baffin Island (Big Round Lake) that had been previously compared in CA posts. Rather than interpreting the two series in opposite orientations, as in PAGES2K, they plausibly explained results in terms of common climate changes in the North Atlantic from the Medieval period to the Little Ice Age::
Kulusuk glaciers increased in size ca. AD 1250-1300 and again ca. AD 1350 and AD 1450, precisely when ice caps on Baffin Island (Miller et al., 2012) and Iceland (Larsen et al., 2011) were expanding (Fig. 4). After AD 1450 Kulusuk glaciers continued to expand, as did Langjökull [Hvitarvatn] on Iceland, while evidence from the Baffin ice caps indicates continuous ice cover (Miller et al., 2012). Both Kulusuk and Langjökull glaciers appear to have advanced in two phases, at ca. AD 1450-1630 and ca. AD 1700-1930. Varve thickness and magnetic susceptibility data from a proglacial lake [Big Round] on Baffin Island, if interpreted to reflect glacier size, also reveal two similar distinct glacier advances at these times (Fig. 4) as well as the earlier advance ca. AD 1250-1300 also observed in the Kulusuk record (Thomas and Briner, 2009; Thomas et al., 2010). Taken together, these data are consistent with records from around Greenland that suggest the most extensive glacier advances since the early Holocene occurred between AD 1250-1900, and provide evidence for regionally coherent cooling phases during the Little Ice Age (Grove, 2001).
Balascio et al Figure 5 illustrated this comparison, including direct comparison of the varve thickness series from Hvitarvatn, Iceland (Langjokull) (panel D below) and Big Round Lake, Baffin Iceland (panel B below), to Kulusuk (panel A not shown in excerpt below). In accordance with Gifford Miller’s interpretation that has been supported at CA, Balascio et al interpreted thick varves in Iceland and Baffin Island evidence of increased glacier/icecap size. Figure 2. Balascio et al Figure 5 Original Caption: … (b) Big Round Lake, Baffin Island, varve thickness and magnetic susceptibility (Thomas and Briner, 2009). (c) Baffin Island ice cap activity reconstructed using vegetation kill dates with text showing original interpretations (Miller et al., 2012). (d) Langjökull ice cap, Iceland based on varve thickness from Lake Hvítárvatn (Larsen et al., 2011). Blue shading marks periods of increased glacier size (sustained above average PC1
The above comparison us identical to the comparison shown at CA here, also comparing Hvitarvatn and Big Round varves in consistent orientation with thick varves interpreted as evidence of glacier advance:
Figure 3. From Climate Audit here. Varve thickness (mm). Purple – Hvítárvatn from Miller et al 2012 Figure 2D; blue – Big Round Lake (NCDC sheet 7 column 4) 30-year running mean. Both shown on same mm scale. See here. Hvitarvatn matches panel D of Balascio et al, while Big Round matches panel B.
Discussion
It is gratifying that Bradley agrees with the interpretation of these two series that had been previously advanced at Climate Audit, though, like Kaufman, there is no acknowledgement. Unfortunately Bradley and coauthors did not discuss the implications of their interpretation on PAGES2K and other multiproxy studies using the Big Round Lake varve series – including: Kaufman et al 2009, Ljungqvist 2010, Christiansen and Ljungqvist 2011, Feng et al 2011, Christiansen and Ljungqvist 2012, Ljungqvist et al 2012, Shi et al 2014, Tingley and Huybers 2013 plus PAGES2K- all of which used the Big Round series upside-down according to the interpretation set out by Bradley and coauthors in Balascio et al.
Adoption of the orientation of Big Round varve data used in Balascio et al 2015 ought to require fresh interpretation of all the varve thickness series used in PAGES2K and other multiproxy reconstructions. It would then be third varved series which had been conceded to have been used upside down. A bit of a habit.
The Grand Old Duke of York
Bradley was a coauthor of Kaufman et al 2009 which used the Big Round series in the opposite orientation to the one adopted in Balascio et al 2015. However, there’s little reason to expect that Bradley would be troubled by using the same data in opposite orientation in two different papers. CA readers will recall that Bradley, as a coauthor of Kaufman et al 2009 acknowledged in a corrigendum that they had used contaminated Korttajarvi upside down and issued a correction to their series, but as coauthor of Mann et al 2008, Bradley denied that they had used contaminated data, let alone upside down.
I guess that we can say that, in Bradley’s hands, proxies are like the Grand Old Duke of York in the nursery rhyme:
And when they were up, they were up,
And when they were down, they were down,
And when they were only half-way up,
They were neither up nor down.