Simetrical’s Recent Comments

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  Non-obvious predictions

  "Once again: what part of this 10 years of validation of what a climate model from a state of the art which is now ancient, do you guys find unsatisfactory?
  http://gristmill.grist.org/images/user/6932/hansen88.gif" ...

  Well, I can't evaluate that image better than by sort of squinting at it, so bear with me.  Assuming that the image was produced from 1988 models, I can see the models roughly correspond to reality from 1988 to 1998.  But again, just from looking at it, the correspondence is not striking.  In fact it seems to me that if you were extrapolate a linear fit on temperatures from 1960 to 1988, then add some random bumps, you would do about as well.  The trough around 1996 or so in models B and C does a bit better than that, granted, but not enough to make the resemblance particularly remarkable, as far as visual inspection goes.

  So basically, what I'm looking for is a model that made a prediction that required CO_2 to be the cause of the warming.  Something that just extrapolates prior trends doesn't say anything about the causes of those trends.  Now, perhaps the graph you posted is an example of such a model, but I can't see that from just looking at it.  Do you have any more precise analysis?  For instance, something that successfully predicted a substantial change in an existing trend, repeatedly, with comparison to the performance of other models that were considered comparably serious at the time the original was released?

  Mind you, I'm willing to accept that on the balance of the evidence, human-released CO_2 is probably causing global warming.  I haven't seen anything that convinces me that it's very likely, or almost certain, as various climatologists say it is.  I have read the IPCC AR4 FAQ, but that didn't really answer my questions.On 'Climate models are unproven'--Actually, GCM's have many confirmed successes under their belts posted 1 year, 10 months ago 13 Responses