Hey Ya! (mal)

Interesting news this weekend. Apparently everything we’ve done in our entire careers is a “MASSIVE lie” (sic) because all of radiative physics, climate history, the instrumental record, modeling and satellite observations turn out to be based on 12 trees in an obscure part of Siberia. Who knew?

Indeed, according to both the National Review and the Daily Telegraph (and who would not trust these sources?), even Al Gore’s use of the stair lift in An Inconvenient Truth was done to highlight cherry-picked tree rings, instead of what everyone thought was the rise in CO2 concentrations in the last 200 years.

Al Gore apparently confusing a CO2 curve for a tree

Who should we believe? Al Gore with his “facts” and “peer reviewed science” or the practioners of “Blog Science“? Surely, the choice is clear….

Yamal sub-fossil larch trees in river sedimentMore seriously, many of you will have noticed yet more blogarrhea about tree rings this week. The target de jour is a particular compilation of trees (called a chronology in dendro-climatology) that was first put together by two Russians, Hantemirov and Shiyatov, in the late 1990s (and published in 2002). This multi-millennial chronology from Yamal (in northwestern Siberia) was painstakingly collected from hundreds of sub-fossil trees buried in sediment in the river deltas. They used a subset of the 224 trees they found to be long enough and sensitive enough (based on the interannual variability) supplemented by 17 living tree cores to create a “Yamal” climate record.

A preliminary set of this data had also been used by Keith Briffa in 2000 (pdf) (processed using a different algorithm than used by H&S for consistency with two other northern high latitude series), to create another “Yamal” record that was designed to improve the representation of long-term climate variability.

Since long climate records with annual resolution are few and far between, it is unsurprising that they get used in climate reconstructions. Different reconstructions have used different methods and have made different selections of source data depending on what was being attempted. The best studies tend to test the robustness of their conclusions by dropping various subsets of data or by excluding whole classes of data (such as tree-rings) in order to see what difference they make so you won’t generally find that too much rides on any one proxy record (despite what you might read elsewhere).

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So along comes Steve McIntyre, self-styled slayer of hockey sticks, who declares without any evidence whatsoever that Briffa didn’t just reprocess the data from the Russians, but instead supposedly picked through it to give him the signal he wanted. These allegations have been made without any evidence whatsoever.

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