Kudos to RealClimate’s Honesty and Sincerity

And no, I am not being sarcastic.

It’s just that (finally!) there is a RC claim that can be compared to the real world; next to it, a good dose of outright sincerity (surely it must have been there before,  perhaps buried in the polemic…)

From What the IPCC models really say (May 12, 2008):

• Claims that GCMs project monotonic rises in temperature with increasing greenhouse gases are not valid. Natural variability does not disappear because there is a long term trend. The ensemble mean is monotonically increasing in the absence of large volcanoes, but this is the forced component of climate change, not a single realisation or anything that could happen in the real world.
• [...]
• Over a twenty year period, you would be on stronger ground in arguing that a negative trend would be outside the 95% confidence limits of the expected trend (the one model run in the above ensemble suggests that would only happen ~2% of the time).

Note that even the fabled 20-year negative trend may still be interpreted as consistent with at least one model run.

But it’s a good step in the right direction: bringing back climate science from its forcings cage to the actual world…

Climate Models Are Irrelevant, and Latest IPCC Models a Regression

(many thanks to LM for pointing this out)

• “[GCM] model outputs at annual and climatic (30‐year) scales are irrelevant with reality“
• “model predictions are much poorer that an elementary prediction based on the time average“
• “The GCM outputs of AR4, as compared to those of TAR, are a regression in terms of the elements of falsifiability they provide, because most of the AR4 scenarios refer only to the future, whereas TAR scenarios also included historical periods“

Those are not the insane ramblings of yours truly, but the conclusions of D. Koutsoyiannis et al’s “Assessment of the reliability of climate predictions based on comparisons with historical time series“, a poster presentation at the European Geosciences Union General Assembly 2008 in Vienna, Austria, 13‐18 April 2008.

Of course, it’s only a poster presentation…and of course, there was really no space at all to talk about it in the news, eg on the BBC.

Well, there is one good thing that has come out of this though: some explicit references in RealClimate about the need to have “a very civilized and friendly chat“, “to be respectful, sincere, and show courtesy in our criticism, even when we argue why we think that a paper has flaws“, and that “we some day may be mistaken, so it’s important to be humble and check our drafts amongst ourselves“.

This will mean no more verbal attacks about “negationism”, and few if any displays of condescension. Sure it will… 

Climate Change Detection/Attribution? Some Hope!

Curious situation on the website of the PCMDI - the “Program for Climate Model Diagnosis and Intercomparison”, at the Lawrence Livermore National Laboratory, with a stated mission:

to develop improved methods and tools for the diagnosis and intercomparison of general circulation models (GCMs) that simulate the global climate

Here’s what the PCMDI has to say about “devising robust statistical methods for climate-change detection/attribution“:

Coming soon…

That’s it.

Wow.

Sure.

Well, it looks like we will just have to be patient. We will be told how to detect and attribute climate change…one day, perhaps after some considerable amount of time will have ben spent in the frankly rather wasteful efforts of mostly comparing climate models to each other, rather than to the actual world.

p.s.: Applause to the PCMDI for their frankness:

The need for innovative analysis of GCM climate simulations is apparent, as increasingly more complex models are developed, while the disagreements among these simulations and relative to climate observations remain significant and poorly understood. The nature and causes of these disagreements must be accounted for in a systematic fashion in order to confidently use GCMs for simulation of putative global climate change.