"Add experimentally proven green houses gases to the atmosphere as much as you want because there is no "model" that can prove it will harm us." (a rough synopsis of how Larry's comments read to me not a real quote)

What seems to be getting lost in the debates over the accuracy and details of modeling is that experimental evidence (Venus {yes this ties in with space}, Mars, Measured infrared trapping properties) combined with common sense alone strongly suggests action is needed with or without climate models.

We agree that the current climate models are not validated.

We agree that there is plenty of variation they can't account for.

We agree that a program is only as good as its underlying assumptions.

What I don't agree with is that all of these are a basis for shucking common sense or a reason to assume the models are not even in the ball park of the magnitude of the impact of CO2 on top of independent natural climactic variation.

For all your claims of computer expertise you must deal with a very limited number of variables not to be able to understand the value of approximate solutions. Engineers use these all the time.

I also find it hard to believe you make every important decision based on scientific certainty. When will you respond to that issue Larry?

Let me also ask if you have ever actually programmed a computer model from underlying theory?

Your comments on atmospheric re-entry modeling seem simplistic to me based on my experience with only a 4 equation (multiple nonlinear) system (affinity chromatography).

Do you claim your example model has to account for anywhere near as many variables as a climate model?

Do you claim your experimental data has as much potential error in it as climate models?

Do you claim measurement error has no impact on the ease of validating a model?

Do you think only exact solutions are of value?

Do you think even 50% of government, corporate, or individual policy decisions are based scientifically validated conclusions or correlations?

Do you agree that climate models are limited in complexity to a practical extent by computational power?

Do you agree that the number of variables in a given model also needs to be limited in order to minimize the risk of false fit?

Are you unaware than many natural cycles follow a sine wave? (new question)

Does a natural sine wave system mean an independent geometric or exponential function added on top of it is no concern? (new question - I know you are a math major and should get the right answer here)

Do you honestly believe that a model of such a geometric or exponential system alone has no value if it does not model the sine wave system as well? (new question )

Do you honestly believe that if there is a negative temperature feeback loop associated with CO2 that it will result in a convenient 0 impact scenario?

Are you aware that even buffered systems eventually destabilize when an excess of one reactent keeps getting pumped into a system? (new question)

Have you ever heard of LeChatlier's principle (related to chemical equilibrium - spelling probably butchered)? (new question)

Are you aware that major climate changes have occured frequently and that it is quite possible our current conditions represent an unstable rather than stable equilibrium?

Are you aware that in an unstable equilibrium situation increased oscillation can lead to a major shift in equilibrium point even if the mean stays constant prior to the shift?

Are you aware that Venus' cloud cover reflects far more sunlight than the Earth's yet this albedo effect is still swamped by the heat trapping impact of its thick CO2 atmosphere (new question - yes Venus has far more CO2 but the temperature rise at issue is also far larger)?

I've rephrased all the important modeling questions I've asked you which you have not answered and any experienced modeler should be able to answer in simple yes or no format so you don't have the "I don't have time" excuse which you seem to think applies to you but not to me. Some new ones have been added to address some good points you have raised that I don't think I've addressed yet.

You find the time to make the same statements over and over with different phrasing but keep avoiding these questions/issues which I have stated over and over with different relevant examples. I get your points. Changing phrasing will not change that. I agree with most of your facts but disagree with your conclusions based on the issues above which you keep avoiding.

I'm not a climate or a modeling expert Larry. However, having some modeling experience and a lot of chemical process experience (global warming involves the same fundamental processes on a far larger and more complicated scale) I do understand the relevance of all these questions. Do you?

Regards,
Mark

PS I'm quite interested to see how all of the people involved in this debate would answer these questions.