Search Results for: marcott holocene

Ground-truthing Marcott

The MD99-2275 core offshore Iceland is a very high-resolution ocean sediment core, results of which over the past millennium have been discussed here from time to time. Alkenone and diatom results for the last millennium have been available for about 10 years. MD99-2275 results were used in PAGES2K Arctic and Hanhijarvi 2013, also Trouet et […]

Marcott’s Dimple: A Centering Artifact

One of the longstanding CA criticisms of paleoclimate articles is that scientists with little-to-negligible statistical expertise too frequently use ad hoc and homemade methods in important applied articles, rather than proving their methodology in applied statistical literature using examples other than the one that they’re trying to prove. Marcott’s uncertainty calculation is merely the most […]

How Marcottian Upticks Arise

I’m working towards a post on the effect of Marcott re-dating, but first I want to document some points on the methodology of Marcott et al 2013 and to remove some speculation on the Marcott upticks, which do not arise from any of the main speculations. In the graphic below, I’ve plotted Marcott’s NHX reconstruction […]

Marcott’s Zonal Reconstructions

I’m going to do a detailed post on my diagnosis of the Marcott uptick, but before I do so, I want to comment on the reconstructions for NH and SH extratropics, neither of which have attracted sufficient notice though both are very remarkable. In a substantive sense, because orbital changes have different effects on NH […]

Marcott Mystery #1

Marcott et al 2013 has received lots of publicity, mainly because of its supposed vindication of the Stick. A number of commenters have observed that they are unable to figure out how Marcott got the Stick portion of his graph from his data set. Add me to that group. The uptick occurs in the final […]

Gergis and Law Dome

In today’s post, I’m going to examine Gergis’ dubious screening out of the Law Dome d18O series, a series that has been of long-standing interest at Climate Audit (tag). Gergis et al 2016 stated that they screened proxies according to significance of the correlation to local gridcell temperature. Law Dome d18O not only had a significant […]

The “Blade” of Ocean2K

I’ve had a longstanding interest in high-resolution ocean proxies (with posts as early as 2005 – see Ocean Sediment tag) and had already written detailed reviews of many of the individual high-resolution series used in Ocean2K (e.g. here here here here here here). In these prior discussions, the divergence between the 20th century proxy data and 20th century instrumental […]

Important New North American East Coast Proxy Data

One of my long-standing interests is the location of ocean sediment series that enable apples-to-apples comparison of the 20th century to the mid-Holocene.   These are not nearly as common as one would think.   Ocean sediment series covering the Holocene typically stop prior to the 20th century due to core recovery problems and, on […]

SH Proxies: Peru d18O

One of the hidden assumptions of proxy reconstructions, as carried out by IPCC authors, is that each “proxy” has a linear relationship to temperature plus relatively low-order red noise. Under such circumstances, the noise will cancel out in a linear combination of proxies (reconstruction) and a “signal” will emerge. However, I’ve never seen any author […]

Rosenthal et al 2013

There has been considerable recent attention to Rosenthal et al 2013: WUWT here, Judy Curry here, Andy Revkin here. The article itself presents a Holocene temperature reconstruction that is very much at odds both with Marcott et al 2013 and Mann et al 2008. And, only a few weeks after IPCC expressed great confidence in […]