# Reliability,accuracy, implications and repercussions of this new global warming study?
**URL:** https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190
**Category:** Great Debates
**Created:** [October 14, 2013, 5:53am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190 "2013-10-14T05:53:09Z")
**Posts on this page:** 14
**Page:** 2
### Author:  [@Richard\_Parker](https://boards.straightdope.com/u/Richard_Parker)
#### Post date: [October 15, 2013, 6:36pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/21 "2013-10-15T18:36:51Z")
> [@brazil84](#):
>
> As far as I know, the mainstream view of the last 100 years – in terms of climate – does not change much from year to year.
But the hindcasting goes back a lot further than that. According to **Kimstu** ’s citation, they’re checking for accuracy in the Holocene, last Millenium, etc.
> [@brazil84](#):
>
> \*f someone showed me a model which (1) matched historical data which is known to be accurate but could not have been known to the modeler; and (2) matched the data well enough that it is very unlikely that the modeler was simply lucky, then I would take it seriously despite my earlier statements about prediction.
I think the “could not have been known” seems like a pretty strict check on cheating, but these otherwise seem like reasonable criteria. Having skimmed **Kimstu** ’s cite, I can’t say whether or not that is the case with the CMIP5 because the language is too technical for my small brain.
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### Author:  [@brazil84](https://boards.straightdope.com/u/brazil84)
#### Post date: [October 15, 2013, 6:53pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/22 "2013-10-15T18:53:03Z")
> [@Richard\_Parker](#):
>
> But the hindcasting goes back a lot further than that.
I wasn’t aware of that. Anyway, I doubt that the mainstream view changes much from year to year. And when it does change, I doubt it changes definitively on that time scale.
> [@](#):
>
> I think the “could not have been known” seems like a pretty strict check on cheating, but these otherwise seem like reasonable criteria. Having skimmed **Kimstu** ’s cite, I can’t say whether or not that is the case with the CMIP5 because the language is too technical for my small brain.
Well I think it’s important to be strict. A lot of people, perhaps a majority, will cheat (either consciously or subconsciously) if they think they can get away with it.
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### Author:  [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)
#### Post date: [October 24, 2013, 10:54pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/23 "2013-10-24T22:54:46Z")
> [@Richard\_Parker](#):
>
> Are there climate scientists who consider it “testing” to check whether the model accurately models the known past?
>
> I would have thought that accurate representation of what we already know happened is a necessary but not sufficient condition for acceptance as a climate model.
It’s sot of maddening to actually find out exactly what you are asking about. The modelers seem to claim that “of course” their models exactly predict the past, even to the point of showing dips due to volcanic eruptions, and rising temps from El Nino years.
The skeptics, being skeptical, tend to insist they also match the last 17 years of “climate” change, which none of them do. Not even close.
But then the modelers point out the wide error margins and because they actually are very wide, they claim the complete lack of rising temps was also predicted. It seems, to the untrained eye, that nothing will prove a model wrong.
Even if all the models are wrong, they aren’t “really” wrong, they just need to be adjusted, and it doesn’t matter that they failed to predict what happened, because science is self correcting, and they adjust the models after the fact because that is how science works.
Your average person shrugs the shoulders and scratches the head and since they are experts and all that, they must be right.
Since most people “know” global warming is happening, it must be happening. And if a model doesn’t get it right, it just needs fixing. It doesn’t mean there isn’t global warming, just because the records show no global warming. Since the science says it must be happening, and all the models agree, then global warming must be happening. It’s science.
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### Author:  [@Richard\_Parker](https://boards.straightdope.com/u/Richard_Parker)
#### Post date: [October 24, 2013, 11:33pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/24 "2013-10-24T23:33:15Z")
It is a real problem that the thing we’re trying to predict cannot be reliably measured except over decades. It means that gold standard tests of our science won’t come around until its too late. But the question facing us is what does the most reliable data we have right now say, based on our best scientific theories, about where the climate is going in the next century. That science may be, by its very nature, impossible to get as close to certainty as, say, theories about early human migration or something else immediately falsifiable when a new discovery comes along. That doesn’t mean it isn’t science, or that it isn’t the best available prediction about what we should be doing.
I don’t think any mismatch between short-term trends and the models suggests the models aren’t the best available evidence. First, I’m not sure what you represent is true. And second, even if it is, I’m not especially troubled if the models fail to make precise, short-term predictions unless they claimed to be able to do so. I assume there is much more variability in any year or even any decade’s weather than there is in overall global climate trends.
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### Author:  [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)
#### Post date: [October 25, 2013, 1:40am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/25 "2013-10-25T01:40:29Z")
> [@Richard\_Parker](#):
>
> It is a real problem that the thing we’re trying to predict cannot be reliably measured except over decades. It means that gold standard tests of our science won’t come around until its too late.
A legitimate question is whether it’s possible to accurately model the future climate (due to chaotic nature).
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### Author:  [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)
#### Post date: [October 25, 2013, 2:23am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/26 "2013-10-25T02:23:31Z")
> [@Richard\_Parker](#):
>
> It is a real problem that the thing we’re trying to predict cannot be reliably measured except over decades.
Not anymore. It’s been decades now, and the predictions made 20 years ago have turned out to be wrong.
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### Author:  [@brazil84](https://boards.straightdope.com/u/brazil84)
#### Post date: [October 25, 2013, 10:13am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/27 "2013-10-25T10:13:33Z")
> [@RaftPeople](#):
>
> A legitimate question is whether it’s possible to accurately model the future climate (due to chaotic nature).
Yes, how does anyone know about the “except over decades” part?
I mean, if a television psychic were to tell you that he cannot make short term predictions, but he can make extremely accurate predictions about events 30 years in the future, you would naturally be very skeptical. You would say “Gosh, it sure is convenient for you that we have to wait 30 years to test your claims.”
As far as I know, there’s no evidence at all that it’s easier to predict climate 30 years from now than 5 years from now.
Besides which, as **Fx** points out, one can go back and check old predictions. For example Hansen’s famous prediction from the 80s which turned out to be wrong.
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### Author:  [@brazil84](https://boards.straightdope.com/u/brazil84)
#### Post date: [October 25, 2013, 10:15am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/28 "2013-10-25T10:15:32Z")
Another thing about Hansen’s computer model: It matched history very well.
So presumably people like **chronos** would have accepted it as authoritative on the ground that it had been tested and passed the test. After all, Hansen is not an idiot, right?
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### Author:  [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)
#### Post date: [October 25, 2013, 2:34pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/29 "2013-10-25T14:34:24Z")
> [@brazil84](#):
>
> Yes, how does anyone know about the “except over decades” part?
>
> I mean, if a television psychic were to tell you that he cannot make short term predictions, but he can make extremely accurate predictions about events 30 years in the future, you would naturally be very skeptical. You would say “Gosh, it sure is convenient for you that we have to wait 30 years to test your claims.”
>
> As far as I know, there’s no evidence at all that it’s easier to predict climate 30 years from now than 5 years from now.
>
> Besides which, as **Fx** points out, one can go back and check old predictions. For example Hansen’s famous prediction from the 80s which turned out to be wrong.
Of course, ignore that climate scientists already point out that short term predictions are not the main point of climate science. And it is really silly to go back on what the vast majority of scientists already accept as the most likely explanation of the current warming.
There is a reason why [Hansen continues to be recognized](http://www.sciencefestival.co.uk/news/environment/dr-james-hansen-receives-edinburgh-medal), what the false skeptics do not want others to know is that there are very good reasons why his. He was more accurate than the ones claiming that there was not going to be warming.
> **[What do we learn from James Hansen's 1988 prediction?](https://skepticalscience.com/Hansen-1988-prediction-advanced.htm)**
>
> \Subsequent comparison of observations with predictions find that Hansen's Scenario B (which most closely matched the level of CO2 emissions) shows close correlation with observed temperatures.\
> [@](#):
>
> What the science says…
>
> Although Hansen’s projected global temperature increase has been higher than the actual global warming, this is because his climate model used a high climate sensitivity parameter. Had he used the currently accepted value of approximately 3°C warming for a doubling of atmospheric CO2, Hansen would have correctly projected the ensuing global warming.
> [@](#):
>
> Hansen’s Accuracy
>
> Had Hansen used a climate model with a climate sensitivity of approximate 3°C for 2xCO2 (at least in the short-term, it’s likely larger in the long-term due to slow-acting feedbacks), he would have projected the ensuing rate of global surface temperature change accurately. **Not only that, but he projected the spatial distribution of the warming with a high level of accuracy.**** The take-home message should not be “Hansen was wrong therefore climate models and the anthropogenic global warming theory are wrong;” the correct conclusion is that Hansen’s study is another piece of evidence that climate sensitivity is in the IPCC stated range of 2-4.5°C for 2xCO2.**
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### Author:  [@sleestak](https://boards.straightdope.com/u/sleestak)
#### Post date: [October 26, 2013, 7:03am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/30 "2013-10-26T07:03:48Z")
> [@Chronos](#):
>
> And if the model they were using weren’t tested, it wouldn’t be published. Despite what some might think, scientists aren’t idiots.
Bwahahaha!
That is the funniest thing I have read in a while.
The vast majority of the models used over estimate temp increases by a large amount.
[link](http://www.drroyspencer.com/wp-content/uploads/CMIP5-73-models-vs-obs-20N-20S-MT.png)
There are more graphs showing the models overstate temps. Judith Curry covers this area well.
How anyone can claim that the climate models are solid over long periods when they haven’t been around long enough to verify the long term performance really confuses and baffles me. What baffles me even more is the response of the warmists. Instead of admitting the models at this time are off by a large amount, they resort to name calling. Calling people things like ‘false skeptics’ and the like.
The models, at this point, are not complex enough to be accurate. They don’t do clouds well. They don’t do rain or snow well. They don’t do dust well. They did do some curve fitting to make the models mimic the past but there is no reason to believe they will be accurate in the future.
Having said that, cleaner energy is a good thing. New energy sources are a good thing. But the world ain’t gonna melt any time soon.
Slee
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### Author:  [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)
#### Post date: [October 26, 2013, 7:16am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/31 "2013-10-26T07:16:01Z")
> [@sleestak](#):
>
> Bwahahaha!
>
> That is the funniest thing I have read in a while.
>
> The vast majority of the models used over estimate temp increases by a large amount.
> [link](http://www.drroyspencer.com/wp-content/uploads/CMIP5-73-models-vs-obs-20N-20S-MT.png)
>
> There are more graphs showing the models overstate temps. Judith Curry covers this area well.
No they do not, and you should had learned by now that relying on Spencer is really silly.
> **[The 5 stages of climate denial are on display ahead of the IPCC report](https://skepticalscience.com/5-stages-climate-denial-on-display.html)**
>
> The fifth Intergovernmental Panel on Climate Change (IPCC) report is due out on September 27th, and is expected to reaffirm with growing confidence that humans are driving global warming and climate change. In anticipation of the widespread news...
> [@](#):
>
> Once people move beyond denying that the problem exists, they often move to the next stage, denying that we’re responsible. John Christy and Roy Spencer took this approach by disputing the accuracy of global climate models in The Daily Mail and The Christian Post, respectively. Spencer was quite explicit about this:
>
> > [@](#):
> >
> > …we deny “that most [current climate change] is human-caused, and that it is a threat to future generations that must be addressed by the global community.”
>
> Christy and Spencer made their case by comparing the outputs of 73 climate models to satellite temperature measurements, and showing that the models seemed to predict more warming than has been observed. But the comparison was not of surface temperatures, or of the lowermost layer of the atmosphere, or even any measurement global average temperatures. They specifically looked at measurements of the temperature of the middle troposphere (TMT) in the tropics.
>
> There’s certainly nothing wrong with examining this particular subset of temperature data, but it’s a bit of an odd choice on its face. The real problem lies in the fact that satellite measurements of TMT are highly uncertain. In fact, estimates of the TMT trend by different scientific groups vary wildly, despite using the same raw satellite data.
>
> Another problem is that the stratosphere (the layer of the atmosphere above the troposphere) is cooling – an expected consequence of the increased greenhouse effect. But some of the cooling stratosphere bleeds into the TMT data, leading to another cool bias. While there is a discrepancy between model simulations and measurements of tropical troposphere temperatures, it’s not clear how much (if any) is due to the models being wrong, and how much is due to errors in the measurements. As a U.S. Climate Change Science Program report co-authored by John Christy concluded,
>
> > [@](#):
> >
> > ```
> > "This difference between models and observations may arise from errors that are common to all models, from errors in the observational data sets, or from a combination of these factors. The second explanation is favored, but the issue is still open."
> >
> > ```
>
> However, in mainstream media interviews and editorials, Christy and Spencer always fail to mention the possibility that the problem could lie more in the measurements than the models, which frankly is intellectually dishonest. Additionally, climate models have done very well in projecting long-term global surface temperature changes.
> **[Comparing Global Temperature Predictions](https://skepticalscience.com/comparing-global-temperature-predictions.html)**
>
> At this point in the Lessons from Past Climate Predictions series, we're running out of global temperature predictions to evaluate, so now may be a good time to summarize what we've seen thus far. So let's just get right to the good stuff:
> [@](#):
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> As you can see in Figure 1, the more mainstream climate science predictions (generally the warmer colors) have mostly done well (Kellogg in 1979 being the main exception), and the “skeptics” (generally cooler colors) have generally done rather poorly, universally predicting less warming than has been observed.
As for Spencer, even conservative scientists have noticed how his toy models are made mostly to mislead rather than to do proper science:
> **[Just Put the Model Down, Roy](https://bbickmore.wordpress.com/2011/07/26/just-put-the-model-down-roy/)**
>
> For the past few years, Roy Spencer has had a love affair, of sorts, with “simple climate models”. After all, who needs some fancy-schmancy global circulation model (GCM) when you can boil down th…
> [@](#):
>
> I could go on with more nitpicks, but I’m going to stop here, because it should be clear that, once again, Spencer has made a big deal out of something that doesn’t have any evidentiary value. So if, as Spencer claims, “[t]he evidence for anthropogenic global warming being a false alarm does not get much more convincing than this,” then can we please move on? Can Roy PLEASE put his toy model down?
>
> I doubt he will, but maybe he will accept this challenge. Instead of complaining about how biased and awful the peer review system has gotten, he should (at the very least) get a statistician to work with him and do the modeling right, and then submit it for publication in a reputable journal. Personally, I don’t think the work can be saved, even then. However, I think the exercise of working with someone who knows how to properly make statistical inferences would be enlightening for Roy Spencer.
So yes, Spencer is a ‘false skeptic’ because the shoe fits.
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### Author:  [@brazil84](https://boards.straightdope.com/u/brazil84)
#### Post date: [October 26, 2013, 9:38am UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/32 "2013-10-26T09:38:44Z")
> [@sleestak](#):
>
> How anyone can claim that the climate models are solid over long periods when they haven’t been around long enough to verify the long term performance really confuses and baffles me.
Well they do it using the one of the favorite tactics of warmists: Ambiguity.
**chronos** asserted that the models had been “tested” but when I asked him questions about how this testing was actually done, he disappeared.
> [@](#):
>
> What baffles me even more is the response of the warmists. Instead of admitting the models at this time are off by a large amount, they resort to name calling. Calling people things like ‘false skeptics’ and the like.
Well what choice do they have?
The predictions of doom and gloom hinge on the validity of climate models. So if the evidence calls those models into question, you must either reject the evidence or not be a warmist anymore.
> [@](#):
>
> The models, at this point, are not complex enough to be accurate. They don’t do clouds well. They don’t do rain or snow well. They don’t do dust well. They did do some curve fitting to make the models mimic the past but there is no reason to believe they will be accurate in the future.
I agree, the models are obviously wildly overfitted.
> [@](#):
>
> Having said that, cleaner energy is a good thing. New energy sources are a good thing.
Well it depends on the costs and benefits.
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### Author:  [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)
#### Post date: [October 26, 2013, 8:32pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/33 "2013-10-26T20:32:03Z")
> [@brazil84](#):
>
> Well they do it using the one of the favorite tactics of warmists: Ambiguity.
>
> **chronos** asserted that the models had been “tested” but when I asked him questions about how this testing was actually done, he disappeared.
As usual, brazil just ignores what even science museums are reporting:
[http://www.sciencemuseum.org.uk/climatechanging/climatescienceinfozone/exploringwhatmighthappen/2point4/2point4point4.aspx](http://www.sciencemuseum.org.uk/climatechanging/climatescienceinfozone/exploringwhatmighthappen/2point4/2point4point4.aspx)
> [@](#):
>
> Scientists use climate models to investigate the behaviour of the climate system and to simulate how the climate may respond to changes, including the increase in atmospheric greenhouse gases caused by human activities. To enable scientists to asses their accuracy, computer models are also used to simulate historical climate periods. Scientists examine data from model simulations of the present and 20th-century climate and compare them with observations from the same period. The models aren’t perfect, but their general performance at simulating climate patterns and trends gives scientists confidence in the models’ ability to represent the climate.
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### Author:  [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)
#### Post date: [October 26, 2013, 8:50pm UTC](https://boards.straightdope.com/t/reliability-accuracy-implications-and-repercussions-of-this-new-global-warming-study/671190/34 "2013-10-26T20:50:43Z")
Also, besides ignoring the testing that is being done, the usual point from climate contrarians is that climate models need better verification and validation (V&V). There are reasons why they are wrong on that one and the most likely reason is that it would boggle down the current research, just what many powerful interests would like to see.
> **[Do Climate Models need Independent Verification and Validation? | Serendipity](http://www.easterbrook.ca/steve/2010/11/do-climate-models-need-independent-verification-and-validation/)**
>
> A common cry from climate contrarians is that climate models need better verification and validation (V&V), and in particular, that they need Independent V&V (aka IV&V). George Crews has been arguing this for a while, and now Judith Curry...
> [@](#):
>
> A common cry from climate contrarians is that climate models need better verification and validation (V&V), and in particular, that they need Independent V&V (aka IV&V). George Crews has been arguing this for a while, and now Judith Curry has taken up the cry. Having spent part of the 1990′s as lead scientist at NASA’s IV&V facility, and the last few years studying climate model development processes, I think I can offer some good insights into this question.
>
> The short answer is “no, they don’t”. The slightly longer answer is “if you have more money to spend to enhance the quality of climate models, spending it on IV&V is probably the least effective thing you could do”.
>
> The full answer involves deconstructing the question, to show that it is based on three incorrect assumptions about climate models: (1) that there’s some significant risk to society associated with the use of climate models; (2) that the existing models are inadequately tested / verified / validated / whatevered; and (3) that trust in the models can be improved by using an IV&V process.
> [@](#):
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> To summarize, IV&V would be an expensive mistake for climate modeling. It would divert precious resources (experts) away from existing modeling teams, and reduce their flexibility to respond to the science. IV&V isn’t appropriate because this isn’t mission safety-critical software, it doesn’t have distinct development and operational phases, and the risks of software error are minor.
>
> There’s no single point of failure, because many labs around the world build their own models, and the normal scientific processes of experimentation, peer-review, replication, and model inter-comparison already provide a sophisticated process to examine the scientific validity of the models. Virtually all coding errors are detected in routine testing, and science errors are best handled through the usual scientific process, rather than through an IV&V process. Furthermore, there is only a small pool of experts available to perform IV&V on climate models (namely, other climate modelers) and they are already hard at work improving their own models. Re-deploying them to do IV&V of each other’s models would reduce the overall quality of the science rather than improving it.
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