My belief in Global Warming is getting shaky

[Overdog]

Originally Posted by InfiniteNow

Name a speicific model with these accuracy issues to which you are alluding so we can be specific.

Come on, dude, stop trying to avoid the issue. You are the one who accused me of academic dishonesty...address the issues I have raised or bug out.

[Zythryn]

Infi, previously Overdog said 'any of them'.
So if you can find any one that counters his argument, I would think he would then give up his position, right Overdog?

[Overdog]

Originally Posted by Zythryn

Infi, previously Overdog said 'any of them'.
So if you can find any one that counters his argument, I would think he would then give up his position, right Overdog?

Well, I might accord greater credibility, but to be convinced that it is not a matter of opinion, which is my main point, I need Grassl's criteria to be refuted, or see evidence that all four criteria have been met. I will also settle for a minimum of three data points of accurately predicted future projections which are not merely projections of an existing trend.

[Zythryn]

So will one model that meets your stipulation be sufficient, or do you need more?
As a more basic question, if the models have a 'reasonable assumption' of being "true" is that not reason to support throwing less CO2 into the air?
I agree with you (as does just about everyone here I think) that more accuracy is desireable.
As for the reason we can be confident that we understand the impact of the biggest factors, I think that comes from the fact that when we backtest models they are very accurate. If we didn't understand the major factors, the backtesting would not be nearly as close.

[InfiniteNow]

Performance metrics for climate models
(http://www.atmos-chem-phys-discuss.n...2008-print.pdf)


http://ams.allenpress.com/perlserv/?...FBAMS-89-3-303


http://www.atmos-chem-phys-discuss.n...10873-2008.pdf

I also advise the reference sections of each.

[Overdog]

Originally Posted by Zythryn

So will one model that meets your stipulation be sufficient, or do you need more?

Zythryn, I appreciate your input. I really do.

Yes, one model would be sufficient, with the caveat that if the answer is three data points (and not more), then the degree of credibility we accord to the models is still questionable, and dependent on further confirmation over time.

As a more basic question, if the models have a 'reasonable assumption' of being "true" is that not reason to support throwing less CO2 into the air?

This is a question I am happy to discuss, but it is not relavent to the current debate I'm having with InfinateNow. He has accused me of academic dishonesty and "waving my hands". My key point is that this is not the case, that in fact, there is presently no basis for assesing the accuracy of the models.

I agree with you (as does just about everyone here I think) that more accuracy is desireable.
As for the reason we can be confident that we understand the impact of the biggest factors, I think that comes from the fact that when we backtest models they are very accurate. If we didn't understand the major factors, the backtesting would not be nearly as close.

That might be true, but we are talking about nothing less than prophesy. The backtesting that has been done so far only meets part of Grassl's criteria for credibility. My point is simply that the accuracy of the models remain a matter of opinion.

[Overdog]

Originally Posted by InfiniteNow

Performance metrics for climate models
(http://www.atmos-chem-phys-discuss.n...2008-print.pdf)


http://ams.allenpress.com/perlserv/?...FBAMS-89-3-303


http://www.atmos-chem-phys-discuss.n...10873-2008.pdf

I also advise the reference sections of each.

I see you are still ignoring the issues and questions I have raised. You can post as many links as you want, so far most of them have supported my position. Feel free to actually respond to my arguments at any time.

[Zythryn]

But Overdog, this phrase: "reasonably assume they are accurate" is yours. Why would you then say: "That might be true, but we are talking about nothing less than prophesy."
So are the models "reasonable to assume they are accurate"
or
"Nothing less than prophesy"?

As for "there is presently no basis for assesing the accuracy of the models."
I would disagree. If a model gives you accurate back testing I would say that is at least the first step in validation.
Aside from back testing, models predicted a warmer troposphere. Satellite measurements showed a lower temperature than the models. Later, it was discovered an error in the satellite data gave erroneously low temps. After this was corrected, the satellite measurements support the models.
I have read that using models have even led to discovery of some other minor variables to climate. I have not been able to find a source for this yet although if true, it represents a strength of validity in climate models.

The links Infi posted are also excellent and I highly recommend them.

[Zythryn]

Originally Posted by Overdog

I see you are still ignoring the issues and questions I have raised.

Overdog, I have to agree that this statement of yours if intellectually dishonest.
The second link (I haven't read the first yet) speaks DIRECTLY to your concerns.
Again, no one has said the models are perfect. Infi and others have stated they are getting better.
There is even a full graph there listing the performance of various models.
From the conclusion:

Most of the current models not only perform
better, they are also no longer flux corrected. Both
improved performance and more physical formulation
suggest that an increasing level of confidence
can be placed in model-based predictions of climate.

The ONLY aspect of your concerns not addressed may be that a single model's performance is not graphed out for you. Not sure if that data is in the first link or not.

[Overdog]

Originally Posted by Zythryn

But Overdog, this phrase: "reasonably assume they are accurate" is yours. Why would you then say: "That might be true, but we are talking about nothing less than prophesy."

Reasonable assumption is still assumption. Right?
This (and Grassl's criteria) is why I assert that the accuracy of the models is a matter of opinion.

So are the models "reasonable to assume they are accurate"
or
"Nothing less than prophesy"?

They are both, until Grassl's criteria are met or we have another basis for attributing credibility, such as observational evidence that are not merely projections of trends. This is why I argue that at the present time, it remains a matter of opinion. Prophesy is an extraordinary claim, and requires extraordinary evidence.

As for "there is presently no basis for assesing the accuracy of the models."
I would disagree. If a model gives you accurate back testing I would say that is at least the first step in validation.

Yes it is a first step, but Grassl outlines four steps.

Aside from back testing, models predicted a warmer troposphere. Satellite measurements showed a lower temperature than the models. Later, it was discovered an error in the satellite data gave erroneously low temps. After this was corrected, the satellite measurements support the models.
I have read that using models have even led to discovery of some other minor variables to climate. I have not been able to find a source for this yet although if true, it represents a strength of validity in climate models.

I do not dispute any of this. But it isn't relavant to my point.

The links Infi posted are also excellent and I highly recommend them.

I have reviewed them, thanks. They do not address the issues I have raised.