cc: wg1-ar4-ch06@joss.ucar.edu date: Wed, 20 Jul 2005 16:22:16 +0200 from: Stefan Rahmstorf subject: Re: [Wg1-ar4-ch06] Comments on Section 6.3 to: David Rind Dear David, I take from your response that you consider all models that parameterise an important first-order process "conceptual models". I can live with that - but then there are only conceptual climate models around. Any coupled climate GCM that I know of parameterises oceanic convection (and in a very crude way), hence it is a conceptual model in your terms, and there is no fundamental distinction of category between your model and our model. To me the scientific question is not whether an important process is parameterised (many are in GCMs) - it is how well this parameterisation works, for the task at hand. We have tested the feedbacks in great detail (e.g., the cloud, water vapour, lapse rate and snow/ice albedo feedbacks for 2xCO2) in our model and they perform quantitatively within the range simulated by various GCMs. The same is true for many other diagnostics - the model has taken part in model intercomparisons with GCMs and always falls within the range of different GCMs, in a quantitative way. To repeat that point, the quantitative differences between different GCMs are larger than the typical difference between our model and a GCM. So I see no basis for your claim that this model can only "suggest orders of magnitude". That's just plain wrong from all the evidence that I have seen (a lot). If you have concrete evidence to the contrary, other than just knowing one person who happens to agree with you, please come forward with it. Stefan -- To reach me directly please use: rahmstorf@ozean-klima.de (My former addresses @pik-potsdam.de are read by my assistant Brigitta.) Stefan Rahmstorf www.ozean-klima.de www.realclimate.org _______________________________________________ Wg1-ar4-ch06 mailing list Wg1-ar4-ch06@joss.ucar.edu http://www.joss.ucar.edu/mailman/listinfo/wg1-ar4-ch06