The calculation of the PAGES2K regional average contains a very odd procedure that thus far has escaped commentary. The centerpiece of the PAGES2K program was the calculation of regional reconstructions in deg C anomalies. Having done these calculations, most readers would presume that their area weighted average (deg C) would be the weighted average of […]
The revised PAGES2K Arctic reconstruction used 56 proxies (down three from the original 59). Although McKay and Kaufman 2014 didn’t mention the elephant in the room changes in their reconstruction (as discussed at CA here here), they reported with some satisfaction that “decadal-scale variability in the revised [PAGES2K] reconstruction is quite similar to that determined by Kaufman […]
The money quote in the PAGES2K abstract was that there wasn’t any worldwide Little Ice Age of Medieval Warm Period and that AD1971-2000 temperatures were the highest in nearly 1400 years, long before the Medieval Period: There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little […]
PAGES2K (2013) unequivocally stated that the Arctic was “warmest during the 20th century”: The Arctic was also warmest during the twentieth century, although warmer during 1941–1970 than 1971–2000 according to our reconstruction. McKay and Kaufman 2014 did not withdraw or amend the above statement, instead reporting that the revision amplified the cooling trend prior to […]
About eight weeks ago, Jean S postulated that Gavin Schmidt had been involved in writing the documents supporting EPA’s decision denying various petitions for reconsideration of the Endangerment Finding (the “RTP documents“), documents that Mann had cited to the D.C. Court as a supposedly “independent” investigation into allegations against him. Obviously, if Schmidt had been involved […]
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 […]
In today’s post, Jean S and I are going to show that the paico reconstruction, as implemented in the present algorithm, is very closely approximated by a weighted average of the proxies, in which the weights are proportional to the number of measurements. Paico is a methodology introduced in Hanhijarvi et al 2013 (pdf here) […]
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 […]
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 […]
Does it matter whether proxies are used upside-down or not? Maybe not in Mann-world (where, in response to our criticism at PNAS, Mann claimed that it was impossible for him to use series upside-down). But, unlike Mann, Darrell Kaufman acknowledges responsibility for using proxies upside-up. Unfortunately, he and the PAGES2K authors don’t seem to be […]
Climate Audit 