A few days ago, Joelle Gergis closed her letter refusing data stating:

We will not be entertaining any further correspondence on the matter.

Gergis’ statement seems to have been premature. David Karoly, the senior author, who had been copied on Gergis’ surly email and who is also known as one of the originators of the “death threat” story, wrote today:

Dear Stephen, I am contacting you on behalf of all the authors of the Gergis et al (2012) study ‘Evidence of unusual late 20th century warming from an Australasian temperature reconstruction spanning the last millennium’ An issue has been identified in the processing of the data used in the study, which may affect the results. While the paper states that “both proxy climate and instrumental data were linearly detrended over the 1921–1990 period”, we discovered on Tuesday 5 June that the records used in the final analysis were not detrended for proxy selection, making this statement incorrect. Although this is an unfortunate data processing issue, it is likely to have implications for the results reported in the study. The journal has been contacted and the publication of the study has been put on hold. This is a normal part of science. The testing of scientific studies through independent analysis of data and methods strengthens the conclusions. In this study, an issue has been identified and the results are being re-checked. We would be grateful if you would post the notice below on your ClimateAudit web site. We would like to thank you and the participants at the ClimateAudit blog for your scrutiny of our study, which also identified this data processing issue. Thanks, David Karoly Print publication of scientific study put on hold An issue has been identified in the processing of the data used in the study, “Evidence of unusual late 20th century warming from an Australasian temperature reconstruction spanning the last millennium” by Joelle Gergis, Raphael Neukom, Stephen Phipps, Ailie Gallant and David Karoly, accepted for publication in the Journal of Climate. We are currently reviewing the data and results.

The inconsistency between replicated correlations and Gergis claims was first pointed out by Jean S here on June 5 at 4:42 pm blog time. As readers have noted in comments, it’s interesting that Karoly says that they had independently discovered this issue on June 5 – a claim that is distinctly shall-we-say Gavinesque (See the Feb 2009 posts on the Mystery Man.)

I urge readers not to get too wound up about this, as there are a couple of potential fallback positions. They might still claim to “get” a Stick using the reduced population of proxies that pass their professed test. Alternatively, they might now say that the “right” way of screening is to do so without detrending and “get” a Stick that way. However, they then have to face up to the “Screening Fallacy”. As noted in my earlier post, while this fallacy is understood on critical blogs, it is not understood by real_climate_scientists and I would not be surprised it Gergis et al attempt to revive their article on that basis.

One thing we do know. In my first post on Gergis et al on May 31, I had referred to the Screening Fallacy. The following day (June 1), the issue of screening on de-trended series was discussed in comment. I added the following comment in the main post ( responding to comment by Jim Bouldin and others):

Gergis et al 2012 say that their screening is done on de-trended series. This measure might mitigate the screening fallacy – but this is something that would need to be checked carefully. I haven’t yet checked on the other papers in this series.

There was a similar discussion at Bishop Hill. What the present concession means – is that my concession was premature and that the screening actually done by Gergis et al was within the four corners of the Screening Fallacy. However, no concessions have been made on this point.



