by Steve McIntyre, June 30, 2014 in ClimateAudit
Nearly all of the text of this article on an interesting ice core proxy series (James Ross Island) from the Antarctic Peninsula was written in June 2014, but not finished at the time for reasons that I don’t recall. This proxy was one of 16 proxy series in the Kaufman 12K pdf. 60-90S reconstruction.
I originally drafted the article because it seemed to me that the then new James Ross Island isotope series exemplified many features of a “good” proxy according to ex ante criteria that I had loosely formulated from time to time in critiquing “bad” proxies, but never really codified (in large part, because it’s not easy to codify criteria except through handling data.)
Although this series is in the Kaufman 60-90S reconstruction, its appearance is quite different than the final 60-90S reconstruction: indeed, it has a very negative correlation (-0.61) to Kaufman’s final CPS reconstruction. I’ll discuss that in a different article.
Following is mostly 2014 notes, with some minot updating for context.
I’ve articulated with increasing clarity over the years (but present in early work as well) – is that one needs to work outward from proxies that are “good” according to some ex ante criteria, rather than place hope in a complicated multivariate algorithm on inconsistent and noisy data, not all of which are “proxies” for the item being reconstructed. This is based on principles that I’ve observed in use by geophysicists and geologists to combine “good” (high resolution) data with lower quality data.