Mclean debunked (at last)

Better late than never, our Comment on McLean has been formally accepted. It has spent most of the last 6 months on the Editor's desk, awaiting the decision. The peer review was painless apart from the time taken - the three reviewers were all positive and made a small number of helpful suggestions which were easily incorporated into the text. However, the time taken (and it could have been months longer) is something that the AGU might like to think about.

Amusingly, the comment will be published alone, without the customary Reply. Why? Because...McLean et al couldn't muster a reply that was publishable (and not for want of trying, either - it was simply rejected). No doubt this will further strengthen their belief in a widespread climate science conspiracy to suppress their groundbreaking research. Hopefully, disinterested observers will conclude instead that there is simply no valid defence of what they did. I have no idea what they tried to say, although the press release at the time of the original publication shows that they were aware of the obvious criticisms and had some wriggling already well prepared. I have emailed them to ask if they will share their response. If their response had been accepted, it would have potentially taken another two months for our (sequential) revisions, and another month of reviewing. All for a short paper which points out glaring errors that should never have made it into print.

Just to go over the science again...it has been well-known for decades that ENSO/SOI is related to interannual temperature variability. It has also been repeatedly shown that this cannot represent more than a modest part of the total temperature variations and a negligible part of the long-term trend. Evidence for all of this is referenced in our Comment. The primary error of McLean et al is that although they filter out all long term changes, they still claim that the resulting high correlation between SOI and global mean temperature (in the filtered series) has relevance for long term trends. As shown in the toy examples in the comment, this is simply not true - the correlations calculated by their analysis method are completely unrelated to any long-term trends in the underlying data. A secondary error is that they splice together two data sets which have different baselines, which artificially reduces the warming by about 0.2C. A third error is that they claim to identify two flat periods with a breakpoint in the middle (for both SOI and temperature), but their statistical analysis provides no support for this.

Update: Sceptical science has a fuller write-up of it here.

Update2: Someone purporting to be McLean replies in the comments, confirming that he received my email but is not prepared to share his reply, which seems curiously at odds with his bullish attitude regarding his research. What odds it will be published in that septic journal of last resort bastion of quality, the non-ISI-listed E&E (eds: Boehmer-Cristiansen and Peiser) or not at all?