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Economic models fail. What of climate?


SkepticLance
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Swansont

When you suggest I am objecting to science, you are misrepresenting my position and promulgating a lie.

 

I have said that I am sceptical of global climate models. And yes. It is all models. I have not seen clear cut evidence that any are truly reliable, accurate or precise. And this is not objecting to science, or even climate science. It is scepticism of climate models. If you think that an unproven model is science in its totality, it is you that needs educating.

 

Science requires all hypotheses and models to be tested. The standard test system is to make a novel prediction based on the hypothesis or model, which is testable, and then run the test using novel experiment or observation. If any or all climate models are to become genuine science, they must pass this process. That is : They must make a novel prediction, which is tested empirically, and fail to be falsifed. Ideally, this process should be repeated several times to reduce uncertainty.

 

Swansont, you are fully aware of this process. If you are aware of this being done for any or all climate models, please supply particulars.

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Swansont

When you suggest I am objecting to science, you are misrepresenting my position and promulgating a lie.

 

I have said that I am sceptical of global climate models. And yes. It is all models. I have not seen clear cut evidence that any are truly reliable, accurate or precise. And this is not objecting to science, or even climate science. It is scepticism of climate models.

 

Well, I will give you a model that is precise to 10 significant figures. "The global temperature average will be 21.00000000 degrees Celsius forever." I make no guarantees about the model's accuracy, but now you can no longer claim to have never seen a model that is precise. Now, a model that is 100% accurate. "The global temperature average will be 21 plus or minus 1000 degrees Celsius for the next hundred years." So now you have seen both a model that is precise, and one that is accurate. I'm not sure what you mean by "reliable". Both the models I gave you can rely on to be totally worthless, for what it's worth. If you mean one with a decent confidence value, there are plenty of those.

 

If you think that an unproven model is science in its totality, it is you that needs educating.

 

I think that all science is based on unproven models. I've yet to see any model or law of physics that is 100% accurate and 100% precise, nor any that is given 100% confidence.

 

Science requires all hypotheses and models to be tested. The standard test system is to make a novel prediction based on the hypothesis or model, which is testable, and then run the test using novel experiment or observation. If any or all climate models are to become genuine science, they must pass this process. That is : They must make a novel prediction, which is tested empirically, and fail to be falsifed. Ideally, this process should be repeated several times to reduce uncertainty.

 

Actually, I like my models to not make any novel predictions. If I was creating a new hypothesis, I would want it to make some novel predictions to distinguish it from the accepted theory, otherwise it would be hard to disprove the old theory. But that is the only reason to make novel predictions: to distinguish it from the accepted theory, and to provide a way to disprove either the new hypothesis or the accepted theory.

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I have said that I am sceptical of global climate models. And yes. It is all models. I have not seen clear cut evidence that any are truly reliable, accurate or precise.

 

Blah blah blah, blather blather blather... Sayo was spot on.

 

See post #7 (which was a repetition of something which I'd shared with you previously in another thread).

http://www.scienceforums.net/forum/showpost.php?p=441763&postcount=7

 

 

Which of those studies on model reliability, accuracy, or precision that I shared do you think is mistaken?

 

 

Can we end this already? We all know exactly where it's going. :doh:

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The answer given is that the models were unsuited to the type of extreme event that just happened. However, it still remains that mega-millions of dollars have been spent to create economic computer models that could guide the financial world to avoid such crashes as just happened. In spite of all the expertise and all the money invested, these models totally failed to predict exactly the event they were set up to predict.

 

So? What does this have to do with climate?

 

I have always expressed scepticism at the reliability, accuracy/precision of global computer models of climate. After the example of the failure of global economic models, how can anyone have confidence in global climate models?

 

So? What does this have to do with climate? The laws of physics are far more consistent than the laws of human behavior.

 

 

Talk about a textbook logical fallacy.

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Mr Skeptic

I suggest you re-read your first paragraph. It is most unhelpful.

 

You said :

"I think that all science is based on unproven models. I've yet to see any model or law of physics that is 100% accurate and 100% precise, nor any that is given 100% confidence."

 

There are many models that are so close to 100% accurate and precise that any difference is so trivial that it is not even worth mentioning. For example : models of planetary orbits are extraordinarily accurate and precise. They have also been tested by prediction, and novel observation to check those predictions. However, models of global climate - like economic models - have not, as far as I have seen, been so 'proven' by predictive test, and are neither accurate or precise. And their reliability remains very debatable.

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Don't be rude, IA.

 

 

 

 

I agree that is science, and I think the same thing happens with economics and environmental modeling. Just to be clear, I'm not arguing that the models aren't science, I'm just suggesting that economics deserves a little bit more respect. I recognize the commonly accepted technical/academic distinction that makes economics not "science" per se, but that doesn't mean economists can't take a scientific approach when creating an economic model.

 

In pharmaceutical testing they minimize, eliminate or ignore the variables they don't have any control over, such as, oh I don't know, how about whether or not the patient actually swallows the pills you give them, or whether they were honest about their medical backgrounds or other drugs they're taking. Not to mention stuff they may not even be aware of (environmental factors, dietary considerations, accidental overdose, etc etc etc).

 

So, as with economic models, we have to take those early studies with a grain of salt. And the same can be said of environmental models -- even those who create and run them express their limitations for the record. They're not reality. They're only as good as their assumptions.

 

That doesn't mean they're wrong.

 

 

 

We could treat economics as a science, that's no problem. In fact we do that all the time. However, the variables involved are grossly dissimilar to that of climate change, or pharmaceuticals.

 

We've had a detailed theory of climate science for over 150 years, so we can predict with a reasonable degree of certainty how specific forcings will effect the climate.

 

Human behavior and psychology, on the other hand, tends to border on philosophy, and after a century we still haven't been able to produce one equation that can model human behavior reliably. As such, economic models, which are rooted in human psychology, will tend to have much bigger margins of error to account for.

 

They have also been tested by prediction, and novel observation to check those predictions.

 

So have climate models.

 

However, models of global climate - like economic models - have not, as far as I have seen, been so 'proven' by predictive test,

 

 

Did you even read the myriad links provided. They pretty much prove that assumption wrong.

 

and are neither accurate or precise. And their reliability remains very debatable.

 

Yes they are. And no, it's not that debatable.

Edited by I_Pwn_Crackpots
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Mr Skeptic

I suggest you re-read your first paragraph. It is most unhelpful.

 

You said :

"I think that all science is based on unproven models. I've yet to see any model or law of physics that is 100% accurate and 100% precise, nor any that is given 100% confidence."

 

There are many models that are so close to 100% accurate and precise that any difference is so trivial that it is not even worth mentioning. For example : models of planetary orbits are extraordinarily accurate and precise. They have also been tested by prediction, and novel observation to check those predictions. However, models of global climate - like economic models - have not, as far as I have seen, been so 'proven' by predictive test, and are neither accurate or precise. And their reliability remains very debatable.

 

But the problem is that you seem to expect climate models to have the same rigorous standards as simple physics models. Climate is based upon the interactions of many turbulent convection currents, which are far too complex to model perfectly. We cannot gather enough data, and do not have enough computing power, to model climate perfectly. So you cannot expect the same level of precision and accuracy as for simple physics problems. But what you have never mentioned is exactly how accurate and precise you want climate models to be. Perhaps this is so that whenever someone points you to a model that is accurate and precise, you can always say that it is not accurate or precise enough for you, but you never say what would satisfy you.

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To Mr Skeptic

 

I can be convinced, but so far the evidence offered seems to fall within one of two categories, both most unconvincing.

1. Opinions expressed by 'experts'.

2. Historical reconstructions. As I said before, it is easy to have 20:20 hindsight, and achieve this by tweaking models, often without actually understanding why the adjustment must be made.

 

Better evidence is to make a prediction of a novel event before the event happens, and have it prove correct. Trivial and obvious predictions do not count. Simply predicting a warming is insufficient, since I can do that with my graph and ruler, as I pointed out before.

 

To provide a more robust example : currently Greenland is warming and the main body of Antarctica is cooling. If this were reversed, it would be an unexpected and novel event. If a model were to predict this ahead of time, against all 'common sense', it would be powerful evidence of the validity of that model.

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To Mr Skeptic

 

I can be convinced, but so far the evidence offered seems to fall within one of two categories, both most unconvincing.

1. Opinions expressed by 'experts'.

 

I don't know, aren't like ALL scientific papers just "opinions" by experts? They seem to be the only ones qualified to have an opinion on a given topic, whether it is climate change or Higgs bosons.

 

2. Historical reconstructions. As I said before, it is easy to have 20:20 hindsight, and achieve this by tweaking models, often without actually understanding why the adjustment must be made.

 

What makes you think that they don't understand why the adjustments are being made? How do you think reconstructions are made in the first place?

 

 

Better evidence is to make a prediction of a novel event before the event happens, and have it prove correct.

 

No, that's not the definition of evidence. Besides which, climate models already do this, so I don't know what exactly is your beef with climate science.

 

Trivial and obvious predictions do not count.

 

Why don't obvious predictions count? Should the theory of gravity now be considered unreliable because it predicts that all things fall down???? Part of modeling is including all of the obvious predictions

 

And what constitutes a trivial one? The prediction that we cause it, and that it can rise by about 5 degrees centigrade over the next century, is hardly a "trivial" prediction.

 

Simply predicting a warming is insufficient, since I can do that with my graph and ruler, as I pointed out before.

 

Oh really? Wow, that's amazing! It is extraordinary that you can possibly model all those thousands of variables and interactions without the use of supercomputers.

 

Tell me, what else can you do with just a ruler and a graph? Can you also model how galaxies will collide? How tectonic plates will move? How asteroid impacts will affect Earth given ANY parameters? How various species of animals will fare under a given environment and available food supplies? Protein folding?

 

To think, we've spent all that money on supercomputers to help us do all that, when we could have just used a ruler :doh:

 

 

To provide a more robust example : currently Greenland is warming and the main body of Antarctica is cooling. If this were reversed, it would be an unexpected and novel event. If a model were to predict this ahead of time, against all 'common sense', it would be powerful evidence of the validity of that model.

 

The models don't predict that. They predict that the average temperature of the Earth's atmosphere will rise. Now then, I know that this may seem like a shock, but this is something that they are predicting ahead of time. And this is not unexpected. But then, whether or not something is unexpected is irrelevant. In fact, you really don't want any unexpected phenomenon popping up in your scientific model, because then that would show that it is wrong.

Edited by I_Pwn_Crackpots
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SkepticLance, you still have not answered what precision and accuracy you would find acceptable. It is not too hard, how many significant figures do you want for precision, and what percent of the predictions must fall within the error margins to satisfy you? Also, keep in mind that retroactive predictions given new data also count, as it is no fault of the model itself if it is given incorrect data.

 

As to your desire for climate models to predict future conditions. Yes, climate models have correctly predicted future conditions thousands of years in advance. This can be done by leaving out some historical data, and then showing that the model can predict it. I must also point out that doing that is not at all trivial, as the earlier climate models were very bad at it.

 

Obviously, climate models also predict the future. But waiting to see if the predictions are correct may not be an option. If a scientist predicts that a meteor will hit your house, will you want to wait and see if he was right before moving out?

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When you say "WAY off," what precisely was the margin of error to which you're referring?

Follow Swansonts link. It was the thread on global warming computer models and a discussion on Hansen 1988.

In rereading that thread, I thought the conclusion was they used poor terminology, because they used "emission rates" when they appeared to mean atmospheric concentrations

His meaning was rather ambiguous, which means of course that the model could be viewed as accurate or not, depending on which meaning you put to his terminology. (Something that IMO makes it a poor paper BTW.)

 

Anyway, my comment was meant as more tongue in cheek than anything else.;) I really didn't mean to reignite that debate.

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Historical reconstructions. As I said before, it is easy to have 20:20 hindsight, and achieve this by tweaking models, often without actually understanding why the adjustment must be made.

 

Wow, it's a new SkepticLance argument against climate science: the scientists are just cargo culting. They don't really understand what's going on with the climate system. They just fiddle around with their models making changes capriciously without understanding them until they magically reconstruct the historical climate.

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Let me cut through a lot of the nonsense over the last few posts. I put up a legitimate query. If megamillion dollar computer models simulating economic change can fail so badly, why should we have faith in megamillion dollar models simulating climate change?

 

At this point, no-one has answered that query in any manner approaching satisfactorily or convincingly. Instead, as always, I get a bunch of opinions, quibbles, and history.

 

If you are serious about this, then look at the outcomes of those models as science. What evidence is acceptable from a scientific viewpoint? What new data is being produced by those models that can be, and has been tested using empirical methods?

 

The reason I can ask this question, and annoy so many people, is that the answers are simply not available. We get swansont, iNow, and bascule getting irked with me - not because I have done anything wrong - but because they have no solid answers.

 

What I want is good data. Not opinions or interpretations. Data that shows that model outcomes predict things that cannot be predicted in other ways, and do it accurately.

 

I don't mind if the precision is not great, and I don't mind if there is a significant error factor, as long as it is quantified. But I do not want to see anything obvious, like "the world is warming". Gee, I already knew that! Show me good data, on something produced by these models, that could not have been obtained in another way.

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Pointing out the Association Fallacy and the fact that the different modesl have zero to do with each other was both satisfactory and convincing to me. :rolleyes:

 

 

I'll also ask now for the third time. What about the data I shared in Post #7 do you think was problematic or failed to provide solid answers?

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okay, as i said in the second post:

 

Climate models are based on physical laws which HAVE to be obeyed. Economic models are based on filamentous rules that have loopholes and can be broken by fallible humans choosing to ignore/work round them. and the rules themselves are subject to change on a whim. this inherently causes error in any model based upon the rules which will result in complete failure of the model. also the feedback loops of people using the model to make changes to the system to get a more desirable outcome will affect long term predictions significantly.

 

in the climate, the rules never change, they cannot be avoided and the feedback loop of humans changing the system for a more desirable outcome is a lot less pronounced.

 

data that the models work is seen in them retrodicting the global climate to a good degree of accuracy. you say they are no better than a ruler but this is obviously not true as the graph is not a straight line, the model also predicts by how much the temperature will rise and it does so successfully.

 

to sum up the problems with your comparison:

 

1/ you are comparing two completely different types of system, somewhere akin to saying newtonian mechanics fails on a quantum scale so how can we trust the quantum model.

 

2/you are asking for an unrealistic degree of presicion for evidence that the models work correctly. we simply do not have the necessary computing power to get that kind of resolution. in the future we will achieve this.

 

3/ you seem to assume that the people who make climate models just bodge it together like a monkey at a typewriter. this is not so. i suggest that your knowledge of climate modeling is insufficient for you to make valid comments on how useful it is. please do some research into how these models are generated. better yet, start with some simpler models, like heat transfer or fluid flow.

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Let me cut through a lot of the nonsense over the last few posts. I put up a legitimate query. If megamillion dollar computer models simulating economic change can fail so badly, why should we have faith in megamillion dollar models simulating climate change?

 

Same reason we have faith in megamillion dollar computer models simulating economic change. They work within reason. Sure, something unexpected can happen, but how likely is it? Climate models have a far smaller margin of error than economic models, and work on completely different principles.

 

At this point, no-one has answered that query in any manner approaching satisfactorily or convincingly. Instead, as always, I get a bunch of opinions, quibbles, and history.

 

WTF???

 

 

If you are serious about this, then look at the outcomes of those models as science. What evidence is acceptable from a scientific viewpoint? What new data is being produced by those models that can be, and has been tested using empirical methods?

 

I see that you didn't read any of the links?

 

The reason I can ask this question, and annoy so many people, is that the answers are simply not available.

 

Yes they are.

 

We get swansont, iNow, and bascule getting irked with me - not because I have done anything wrong - but because they have no solid answers.

 

If "the Earth's temperature will rise" is not a solid enough answer, then what is? You seem to be the kind of person who will only agree with things they want to hear, not necessarily the science itself.

 

What I want is good data. Not opinions or interpretations. Data that shows that model outcomes predict things that cannot be predicted in other ways, and do it accurately.

 

Well, its right there in those links. If you think your ruler and graph models are better than those from supercomputers, then lets see them.

 

I don't mind if the precision is not great, and I don't mind if there is a significant error factor, as long as it is quantified. But I do not want to see anything obvious, like "the world is warming". Gee, I already knew that! Show me good data, on something produced by these models, that could not have been obtained in another way.

 

But it is quantified. And there really is no other way to make predictions unless you use a model. They are never going to be 100% accurate so I really don't know why you are objecting to their use.

 

 

A question to the rest of you: is SL some sort of global warming denier???? He uses all of the classic arguments and fallacies of a typical GW denier. Because if he is, then I won't spend too much time on this thread. No use in trying to convince the deluded, my time is quite limited.

Edited by I_Pwn_Crackpots
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You need to find something that represents objective and empirically derived data that represents good science.

 

Name one in my list that was not empiricaly derived or which suffered unscientific flaws. It might help if you actually read them prior to offering your comments regarding their content.

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What I want is good data. Not opinions or interpretations. Data that shows that model outcomes predict things that cannot be predicted in other ways, and do it accurately.

 

I don't mind if the precision is not great, and I don't mind if there is a significant error factor, as long as it is quantified. But I do not want to see anything obvious, like "the world is warming". Gee, I already knew that! Show me good data, on something produced by these models, that could not have been obtained in another way.

 

Basically, what you want is a model that is different from the current models. That is what you are asking for in the above post, whether you realize it or not. You are saying that you don't believe the models that we have now, because they are the models we have now.

 

Also, you are demanding that the new models be wrong, and yet also right.

 

Think about it, and you will realize what I said the only conclusion that can be drawn from your demands.

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