Judith Curry: Leaked IPCC Report Discussed In The Mainstream Media
I’m not sure what the IPCC expected when they leaked their report to ‘friendly’ journalists, but I suspect that it was not this article by David Rose.
People have been asking me to comment on the leaked IPCC Final Draft Summary for Policy Makers. Apparently someone in the IPCC made the Report available to ‘friendly’ journalists, as part of a strategy to brief them before the formal release of the Report. I have declined to comment until very recently, since I thought it was best to let the IPCC process play out. Now it is clear that the leaked report has made it into the hands of journalists that were not on the IPCC’s ‘friends’ list. I have now seen a copy of the SPM, and I provided comments to David Rose (and also to another journalist, not sure when that will air).
David Rose quotes me in his article (accurately). I provide below the complete text of the email response I sent to David Rose:
What interests me the most about the AR5 report is how the IPCC is changing its positions and statements relative to the previous AR4 report. It is particularly interesting to see how the different drafts of the AR5 Summary for Policy Makers are changing. I am very grateful that these drafts have been leaked, as these drafts provide important insights into the reasoning behind the IPCC conclusions and confidence levels. The IPCC should of course change its conclusions and confidence levels in response to new scientific evidence and analyses. Because of the rapid pace of publication of papers over the past year that challenge aspects of the AR4 conclusions, the slow ponderous assessment process of IPCC has been apparently having difficulty in responding to and assessing all this, as evidenced by the substantial changes in the drafts.
My main point is this. If there are substantial changes in a conclusion in the AR5 relative to a confident conclusion in the AR4, then the confidence level should not increase and should probably drop, since the science clearly is not settled and is in a state of flux. While there has been a reduction in either the magnitude of the change or in a confidence level in some of the supporting findings, these changes do not seem to have influenced the main conclusion on climate change attribution:
It is extremely likely that human influence on climate caused more than half of the increase in global average surface temperature from 1951-2010.
The ‘extremely likely’ represents an increase in confidence from the ‘very likely’ of the AR4. An increase in confidence in the attribution statement, in view of the recent pause and the lower confidence level in some of the supporting findings, is incomprehensible to me. Further, the projections of 21st century changes remain overconfident. These inconsistencies seems to me to reflect a failure in meta-reasoning by the IPCC. I hope that these inconsistencies are pointed out at the forthcoming meeting in Stockholm.
I have previously argued that the consensus seeking process used by the IPCC acts to create and amplify biases in the science. I have recommended that the consensus seeking process be abandoned in favor of a more traditional review that presents arguments for and against, discusses the uncertainties, and speculates on the known and unknown unknowns. I think that such a process would better support scientific progress and be more useful for policy makers.
Here is the main relevant text on the SPM from Rose’s article: