Kaufman and McKay recently and quietly issued an Arctic2K correction file at NOAA xls here that concedes yet another upside-down series previously pointed out to them at Climate Audit. Once again, they used information from Climate Audit without acknowledgement or credit (see NSF definition of plagiarism here).
Previously, Kaufman and McKay had plagiarized Climate Audit commentary on Hvitarvatn (used upside down by PAGES2k), Igaliku (contaminated data used by PAGES2K) and Kepler Lake (same d18O behaviour as rejected Mt Logan) in the preparation of McKay and Kaufman 2014 (Nature Geoscience). Kaufman had previously plagiarized Climate Audit commentary in his corrigendum to Kaufman et al 2009.
As part of my commentary on McKay and Kaufman 2014, I observed that, even after correcting upside-down use of Hvitarvatn, ocean sediment series P1003 (d18O) was used upside-down to the orientation published by the author (which accorded with usual paleoclimate interpretation). The new list of corrections states of P1003: “Relation between water temp and d18O is inverse; change from postive to negative”
Because the PAICO method used in Arctic2K (see CA here) gives very slight weight to series with few data points (such as P1003), upside-down P1003, unlike upside-down Hvitarvatn, has relatively little impact on the Arctic2K reconstruction. However, as shown previously at CA, the impact of the errors conceded in McKay and Kaufman 2014 is very substantial: a corrigendum to PAGES2K should have been issued and, to borrow a phrase, it’s a “travesty” that it hasn’t been issued.
In previous discussion of the Igaliku series contaminated by modern agriculture but still used by PAGES2K (first identified at CA almost immediately), ClimateBaller Nick Stokes contested the contamination, claiming that pollen accumulation rates were unimpacted by modern agriculture – see here). Even the original authors reject Stokes claim. The list of corrections contains the following pers.comm. from the Igaliku authors:
the massive use of N fertilizers has a strong effect on pollen productivity since the 1980’s. The two top values are clearly outliers and should be removed (mid depth 1.2cm and 3.1 cm). The value just below at 5.5 cm (~ AD 1966) occurred just at the beginning of the effects of recent farming (slight soil erosion due to grazing) but before the major ecological shift at AD 1988. I think we can keep this data point.” C Massa, pers commun, March 11, 2014
It appears to me that the value at 5.5 cm is also contaminated by modern agriculture. I am not reassured by the statement: “I think that we can keep this data point”. In my original discussions, I had argued that singleton proxies should not be used in assessment reports, since there was insufficient knowledge of their behaviour: a population of like proxies ought to be required in order to carry out assessments. the Igaliku example simply shows the wisdom of such a policy. Because the Igaliku series has few data points, it is lightly weighted in the PAICO reconstruction (though not necessarily in other variations) but it ought never have been used.