Category Archives: Medieval

"Explaining" a Positive NAO

Trouet et 2009 posit a positive NAO as the “explanation” of the Medieval Climate Anomaly, pausing only briefly to ask what might have caused a centuries long (“temporally pervasive”) positive NAO, falling back on an arm-waving attribution to a stronger Atlantic meridional overturning circulation: The persistently strong winter MCA NAO and its weakening during the […]

More Z-Score Opportunism

We’ve frequently observed that the reduction of data to standard deviation units (z-scores) is often associated with seemingly opportunistic orientation of the data sets. Often this is buried in the multivariate methodology. Principal components and RegEM can both function to opportunistically provide orientations to “proxies”. In Mann 2008, we saw pretty examples of proxies being […]

Loso: Varves in Alaska

I said that I post the graphic from Loso et al if someone sent it to me today. In fact, Loso et al is online here and interested parties can consult it for themselves. I don’t have time to comment on this study other than very briefly, but here are some of the key graphics.

Another Oceanic MWP Proxy

I’ve been going through the literature and data on ocean sediments looking for proxies with high resolution in the Holocene – something that I discussed a few months ago. Kim et al 2004 and Lorenz et al 2006, two articles by the same group, discuss Holocene SST changes based on alkenones. Most of their proxies […]

The MWP in the Warm Pool

You may recall Hansen’s strange splice of modern instrumental records with a Mg/Ca SST proxy ending in 4320 BP based on a partially dissolved core.’ A couple of months ago, I mentioned a new paper by Newton et al (including L Stott) with a high Warm Pool MWP and briefly discussed Netwon’s presentation at AGU […]

Underwater in the Sierra Nevadas

While we’re re-visiting bristlecones and foxtails, the Here are three interesting online articles, each of which discusses areas in the Sierra Nevada CA, which are now submerged, but where forests grew in the Medieval Warm Period. Many readers of this blog will have read articles about trees being disgorged from receding glaciers and it’s hard […]

Domack on the Larsen 1-A Ice Shelf

Proxy attention seems to have migrated away from things like bristlecones (still waiting for Hughes’ 2002 Sheep Mountain update) to the Antarctic Peninsula ice shelves, with the major break-ups of the Larsen 1-A and 1-B ice shelves. An interesting illustration of NH-SH asymmetry is that the latitude of the Larsen 1-A ice shelf is 64 […]

Lallemand Fjord, Antarctica

In my search for high-resolution ocean sediment records, I stumbled across an interesting 1995 article by Domack et al (Domack of the Larsen Ice Shelf) discussing cores on the west side of the Antarctic Peninsula which were dated over the last 2000 years.

Juckes and the Sargasso Sea

Keigwin’s Sargasso Sea temperature reconstruction, used in Moberg et al 2005, was de-selected by Juckes in what he represented to be the Moberg CVM composite and in making the Union composite (although he managed to use Tornetrask twice ?!? under different names). Although he de-selected the Sargasso Sea temperature reconstruction, he used Moberg’s Arabian Sea […]

Goosse et al 2006 and the MWP

Kevn UK writes in: "I’ve just been to the Climate in the Past and have just spotted the following report “The origin of the European “Medieval Warm Period” H. Goosse, O. Arzel, J. Luterbacher, M. E. Mann, H. Renssen, N. Riedwyl, A. Timmermann, E. Xoplaki, and H. Wanner” “Abstract. Proxy records and results of a […]


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