...but didn't know where to start. At least, that's how I would have titled the Kevin E. Trenberth's blog entry at Nature that Roger Pielke Sr. is highlighting. Professor Pielke gives us the summary with the top 5 quotes from post:
1. “In fact there are no predictions by IPCC at all. And there never have been.”
2. “None of the models used by IPCC are initialized to the observed state and none of the climate states in the models correspond even remotely to the current observed climate.”
3. “Moreover, the starting climate state in several of the models may depart significantly from the real climate owing to model errors. I postulate that regional climate change is impossible to deal with properly unless the models are initialized.”
4. “The current projection method works to the extent it does because it utilizes differences from one time to another and the main model bias and systematic errors are thereby subtracted out. This assumes linearity. It works for global forced variations, but it can not work for many aspects of climate, especially those related to the water cycle.”
5. “However, the science is not done because we do not have reliable or regional predictions of climate.”
Prof. Pielke likes the bits about regional climate effects, since that is his main concern regarding the incompleteness of GCM's, and the overemphasis of greenhouse gases as a climate forcing in particular. I like the parts explaining how the climate models the IPCC uses do not describe current observations and merely offer "what-if" scenarios. I've said many times before that the climate models are tools for sharpening theories and hypothesis, which scientists should then go and find the observations that prove or disprove the model's projections. Using them to affect energy policy change, as opposed to climate change, is not science, but the worst sort of demagoguery. Hopefully more and more scientists will find their voices within the scientific community, so that advocates will no longer mistake silence for "consensus."
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