The graph is presented at page 14 of the Pages newsletter (2003)
Title: “Reconstruction of Low- and High-Frequency Summer Temperature Changes From a Tree-Ring Archive of Fennoscandian Forest-Limit Scots Pine”
The area of sampling was situated between 68° and 70° N, 20° and 30° E, in northern Finland. The area is somewhat 100-600 km (North-)East of Tornetrask (Sweden).

While there is a relative good correlation between local summer (July) temperatures, the result is quite remarkable: an absent MWP, a (relative) warm 16th century, a cold 19th century, warming up to ~1940 and cooling thereafter (another divergence problem…). Seems not very fit to include in the preferred proxies…

The original article was published in 2002 by Eronen ea. (including Briffa) in “The Holocene”.

They should have cleared all this up a long time ago.

Why would they do that? Would that pay better?

Such a climatic event has been posited to be a meteor strike or a very large volcanic eruption. The meteor strike hypothesis has been less popular because a) where’s the crater and b) where’s the iridium anomaly usually associated with a meteor impact?

The alternative is a supervolcanic eruption (also called a superplinian or hyperplinian eruption). This webpage by Ken Wohlenz of Las Alamos National Laboratory hypothesizes that there was a supervolcanic caldera of which Krakatoa was a part, which erupted around 535 CE.

Modern history has its origins in the tumultuous 6th and 7th centuries. During this period agricultural failures and the emergence of the plague contributed to: (1) the demise of ancient super cities, old Persia, Indonesian civilizations, the Nasca culture of South America, and southern Arabian civilizations; (2) the schism of the Roman Empire with the conception of many nation states and the re-birth of a united China; and (3) the origin and spread of Islam while Arian Christianity disappeared.

In his book, Catastrophe An Investigation into the Origins of the Modern World, author David Keys explores history and archaeology to link all of these human upheavals to climate destabilization brought on by a natural catastrophe, with strong evidence from tree-ring and ice-core data that it occurred in 535 AD.

With no supporting evidence for an impact-related event, I worked with Keys to narrow down the possibilities for a volcanic eruption that could affect both hemispheres and bring about several decades of disrupted climate patterns, most notably colder and drier weather in Europe and Asia, where descriptions of months with diminished sun light, persistent cold, and anomalous summer snow falls are recorded in 6th-century written accounts. Writings from China and Indonesia describe rare atmospheric phenomena that possibly point to a volcano in the Indonesian arc.

Although radiocarbon dating of eruptions in that part of the world are spotty, there is strong bathymetric and volcanic evidence that Krakatau might have experienced a huge caldera eruption.

Accordingly, I encouraged a scientific expedition to be led by Haraldur Sigurdsson to the area. The expedition found a thick pyroclastic deposit, bracketed by appropriate radiometric dates, that suggests such a caldera collapse of a “Proto-Krakatau” did occur perhaps in the 6th century. Bathymetry indicates a caldera some 40 to 60 km in diameter that, with collapse below sea level, could have formed the Sunda Straits, separating Java from Sumatra, as suggested by ancient Javanese historical writings. Such a caldera collapse likely involved eruption of several hundred cubic kilometers of pyroclastic debris, several times larger than the 1815 eruption of Tambora.

This hypothetical eruption likely involved magma-seawater interaction, as past eruptions of Krakatau document, but on a tremendous scale. Computer simulations of the eruption indicate that the interaction could have produced a plume from 25 to >50 km high, carrying from 50 to 100 km3 of vaporized seawater into the atmosphere. Although most of the vapor condenses and falls out from low altitudes, still large quantities are lofted into the stratosphere, forming ice clouds with super fine (10 mm)

It’s only interesting because the proxy (which must be from subfossil wood) clearly shows something happening which dramatically reduced tree growth in Siberia nearly simultaneously to the hypothesized eruption.

OK, its not just any data in your posession, but any time series that is available electronically? Even by your standards, McIntyre, this is ridiculous.

I’ve not advocated that "any times series that is available electronically" should be used in a reconstruction. Yakutia/Indigirka was used in Moberg et al 2005 and de-selected by Juckes in his Moberg CVM composite and in his Union reconstruction. Juckes did not report the de-selection. I’d like to know the reason. He said that it wasn’t the data wasn’t “published”. For purposes of analysing Juckes, I take no position on what should be used or not used – I’m merely trying to understand what criteria he used. He has refused to say.