I'm not sure what your point is Arno.  I agree, models are not perfect.  Are you suggesting that we should ignore the implications of the models because they might not be correct. 

You are preaching to the choir Jeff.  I am in 100% agreement that with the viewpoint that global warming is the result of anthropogenic forcing.  My statement (which was worded poorly) was not meant to imply otherwise although I can see how it could be misinterpreted. 

The statement you quoted was in response to Anro's assertion that climate scientists are overconfident about their models.  I strongly disagree with that position.  No climate scientist believes that their model predicts the future with absolute certainty.  They readily acknowledge that there are shortcomings in the models.  That is not however a basis for discarding the models entirely as Anro seems to be implying.   

My choice of words had more to do with semantics than anything else.   "Proof" is not a word scientists use lightly since proving something is far more difficult that disproving something.  As a result a common approach used to prove a theory is to systematically disprove alternative explanations.  This makes the life of GW skeptics easy.  All they need to do to cloud the issue is propose an alternative theory (no matter how absurd it is) and until scientists disprove it the skeptics can claim there is no proof. 

Getting back to my quote, I was simply trying point out to Arno that if he has the impression that scientists are claiming their models are proof of GW that it is likely that he got that impression from someone other than a scientist. 

Nice red herring Arn.  It is true that scientists have been wrong about about many things in the past and that correlation does not equate to causation.  This is not however a basis for dismissing scientific theories as you seem to be implying.  Scientific theories are always changing and evolving as more information becomes available and all we can do is review the latest data and make informed decisions based on it.  Computer models are far from the only evidence that suggests that global warming is caused by CO2 from human activity.  While there are still gaps in the prevailing theory the evidence is overwhelming. 

I doubt anyone will read this but…

First off, I need to agree with Arn on a couple of your points.  From an economic point of view he is 100% correct in stating that the money we are spending to fight global warming has been largely ineffective by almost any measure.  CO2 output continues to grow annually and indications are that the Kyoto Protocol has done little to slow that growth.  In my estimation the economic debate should be divided into two parts.  

1.  Is the current economic response effective?  I think we agree that it is not.  

2.  Is the economic response proportional to the problem?  I believe this is where we differ.

I don't think I’m off base when I say that I think global warming is a much bigger problem than Arn does.  While it is true that the media and environmentalists often overreact that fact alone is not reason to conclude that this issue does not warrant more attention. 

Arn is correct in stating that there could be other causes of the warming.  Unfortunately none of the alternative explanations currently proposed are very plausible.  The solar radiation theory used is a great example.  This theory is often proposed by skeptics but the problem is that that there hasn’t been a trend  

in any index of solar activity since about 1960 that would support that conclusion.  In addi

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... preparing for a river beating!     

Thanks Jeff, I made those points to Arn as well.  I also recomended that he read book called Six Degrees that is coming out in January.  Based on a few reviews it should be pretty good.  In the interest of open-mindedness I am also going to read a few books he recomended while I am away on business.  I think Arn agrees with us more than I originally thought.  The primary difference is that as you noted, he believes the effects of GW will be more limited than I do.  He also has great faith in science to solve the problem.  This is a point we will probably discuss over beers in the future.     

Actually I would consider the spread of disease to be the more dubious (but quite real)... the other effects are better established, especially the changes to rainfall patterns. 

Arn, I suspect part of the problem is that we are looking at 2 separate CBA's (cost benefit analysis).  You seem to like economic analogies so l'll try to illustrate my point using life insurance.  The alanogy is not perfect because policies are not quite as simple as I imply, but I think in this case the analogy is sufficiently accurate. 

There are two ways to determine the CBA of life insurance policies.  One is to compare individual policies and determine which one gives the best coverage for the price.  Clearly, the one that gives you the most bang for the buck (so to speak) should be the one we choose.    

Who's trash talking?  There was no trash talking in there (and lets keep this on the level of a friendly, insightful conversation).  You've yet to address the fundamental flaw in your argument, which is the assumption that the effects of global warming will be minimal.  If that's correct, then fine.  Assuming it should be all about economics then we can wait until it becomes an economic necessity before we do anything about it (at which point in time it will be too late).

If, as all the best science suggests, it is more serious than that then it becomes an economic imperative to do something about it now.  Take a small economic hit now instead of a big one down the road.

Arn, I may be wrong here but it seems to me you are making two arguments that are somewhat contradictory.  If I understand you correctly you believe that we can not accurately predict the future and that we should be skeptical of computer models and scientists who do so. 

On the other hand your CBA assumes 2 things about the future.  First, that the problem is likely to be less significant (rather than more) and second, that science will solve the problem.  It seems incongruent to me to simultaneously base your CBA on assumptions about the future when you do not believe that the future can be accurately predicted.  I prefer a more conservative approach. 

Also, I am not particularly pessimistic about the ability of science to solve problems.  I am just not willing to place all my eggs in that basket.  It would for example be a mistake to smoke cigarettes based on a belief that there will be a cure for lung cancer sometime in the future.  

Also, I think it might be worthwhile to review the fallacies of presumption found here:   http://logicalfallacies.info/

A quick diversion to address my statment on New Orleans, which was not an attempt at humor or a jab but a response to Arn's earlier statment quoted here...