The Royal Meterological Society's evidence to the AR5 inquiry was apparently written by Emily Shuckburgh, incorporating comments from the society's Climate Science Communications Group, including Ed Hawkins, and the governing council. I was struck by their remarks about the reliability of climate models:
Does the AR5 address the reliability of climate models?
13. The Report devotes Chapter 9 to a comprehensive, balanced and realistic evaluation of climate models which is based on the published literature and draws extensively on the results of the Coupled Model Intercomparison Project Phase 5 (CMIP5). As stated in the report (Chapter 9, final draft) climate models are based on physical principles, and they reproduce many important aspects of observed climate. We agree with the report when it states that both these aspects contribute to a “confidence in the models’ suitability for their application in detection and attribution studies and for quantitative future predictions and projections”, and when it notes that “whereas weather and seasonal climate predictions can be regularly verified, climate projections spanning a century or more cannot. This is particularly the case as anthropogenic forcing is driving the climate system toward conditions not previously observed in the instrumental record, and it will always be a limitation.”
This seems an astonishing thing to say, given Ed Hawkins' now iconic graph showing the divergence of the temperature record from the projections, to the verge of falsification. It seems like one story for the climate debate and another for the policymakers.
I've tweeted Ed to see if he can shed any light on the discrepancy.