Global warming computer models are very unreliable.

[iNow]

Obviously the temperature decrease is not an issue here. However, the inaccuracy of the prediction is somewhat typical of what we have seen.

 

Please cite some evidence of other predictions which were not accurate in support of your assertion that this is "typical."

[swansont]

On the business of climate model accuracy :

 

http://www.foxnews.com/story/0,2933,353844,00.html

 

I quote :

 

"When NASA’s James Hansen sounded the alarm in Congress 20 years ago, he predicted that rising concentrations of atmospheric carbon dioxide, or CO2, would drive global temperatures higher by 0.34 degrees Celsius during the 1990s. But surface temperatures increased during that decade by only 0.11 degrees Celsius and lower atmosphere temperatures actually decreased."

 

Obviously the temperature decrease is not an issue here. However, the inaccuracy of the prediction is somewhat typical of what we have seen.

 

 

I think the main issue is that you are quoting Steven Milloy from junkscience, and he's lying.

 

Hansen's predictions stem from the paper he co-wrote ( http://pubs.giss.nasa.gov/abstracts/1988/Hansen_etal.html ) and published that year. In it he give three scenarios, to reflect different changes in greenhouse gases. The scenario that has the ~0.34 ºC increase is scenario A, which has an exponentially increasing radiative forcing. Since those conditions were not present in the 90's, it's dishonest to characterize that as Hansen's prediction.

 

Scenario B had a linear increase in the forcings, which is the best match to what actually happened, and this predicted a temperature increase of between 0.10 - 0.15 ºC.

 

 

http://illconsidered.blogspot.com/2006/04/hansen-has-been-wrong-before.html

http://www.realclimate.org/index.php/archives/2007/05/hansens-1988-projections/

[SkepticLance]

To iNow

 

Let me re-quote from Dr. Frank's article, relating to lousy prediction of cloud formation.

 

" The result is a little embarrassing. The physical uncertainty accumulates rapidly and is so large at 100 years that accommodating it has almost flattened the steep SRES A2 projection of Figure 1. The ±4.4°C uncertainty at year 4 already exceeds the entire 3.7°C temperature increase at 100 years. By 50 years, the uncertainty in projected temperature is ±55°. At 100 years, the accumulated physical cloud uncertainty in temperature is ±111 degrees. Recall that this huge uncertainty stems from a minimal estimate of GCM physical cloud error."

 

Another example I already gave is the predictions of warming in the Arctic, which were seriously inaccurate. As I pointed out by quoting New Scientist, this may be due to a previously unknown oceanic current carrying warm water north.

 

The problem with climate predictions, as I have said repeatedly, is the large number of climate unknowns. Oceanic currents, cloud formation, astronomical phenomena, unpredictable volcanic eruptions etc. I doubt there is anything wrong with the maths or the programming of climate models. Just an awful lot of unknowns and poorly understood 'knowns' preventing accurate prediction.

 

My congratulations to swansont, who actually looked at the reference I posted. You set a good example for intelligent debating.

 

I was not aware of the 3 scenario nature of Hansen's 1988 model, so you have made a good point.

 

However, may I quote from your reference :

 

"for example, during the late 1980s and the 1990s there is a tendency for greater than average warming in the southeastern United States"

 

Correct me if I am wrong, but I do not believe this happened.

[iNow]

You could have just said you cannot cite evidence. You said that inaccuracies are typical. I called you on that claim and requested you cite other studies which had inaccuracies, since you said this was "typical." You instead pivoted back to your original article, hence not supporting your claim of typicality.

 

Like I said. You could have just said that you cannot cite evidence.

[SkepticLance]

Here is another reference to the inaccuracy and lack of reliability of computer climate models. This particular note refers to the fact that the computer models cannot predict regional or local climate change.

 

http://environment.newscientist.com/channel/earth/mg19826543.700?DCMP=NLC-nletter&nsref=mg19826543.700

 

"Poor forecasting undermines climate debate

01 May 2008

Fred Pearce

Magazine issue 2654

"POLITICIANS seem to think that the science is a done deal," says Tim Palmer. "I don't want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain."

 

Palmer is a leading climate modeller at the European Centre for Medium-Range Weather Forecasts in Reading, UK, and he does not doubt that the Intergovernmental Panel on Climate Change (IPCC) has done a good job alerting the world to the problem of global climate change. But he and his fellow climate scientists are acutely aware that the IPCC's predictions of how the global change will affect local climates are little more than guesswork. They fear that if the IPCC's predictions turn out to be wrong, it will provoke a crisis in confidence that undermines the whole climate change debate.

 

On top of this, some climate scientists believe that even the IPCC's global forecasts leave much to be desired. ..."

[iNow]

I read your link. I still see no specific models referenced.

 

Like I said, it would have sufficed if you'd just said, "No, iNow, I am not able to use specific citations to support my contention that inaccuracies are typical. I like to use handwaving to support my assertions, because actual data is too hard to obtain, and would negate the image I'm trying to paint with my slanted and unsubstantiated rhetoric."

[bascule]

"POLITICIANS seem to think that the science is a done deal," says Tim Palmer. "I don't want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain."

 

Comparing mesoscale atmospheric models to GCMs is comparing apples to oranges

[SkepticLance]

To Bascule

 

On this you are correct. But I am building up a pile of references which, together, show that GCMs are neither reliable or accurate. Any reasonable person, having seen the ones so far posted, would agree with me. I have no doubt that I will find, and post, more in future.

 

I realise that refering to authority is not solid debate. However, sometimes it is good to see what the great are saying and thinking. Just came across a reference from the great Freeman Dyson.

 

http://www.edge.org/documents/archive/edge219.html#dysonf

 

I quote :

 

"My first heresy says that all the fuss about global warming is grossly exaggerated. Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the computer models. Of course, they say, I have no degree in meteorology and I am therefore not qualified to speak. But I have studied the climate models and I know what they can do. The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models."

 

 

There is a lot more to this article - none of which indicates confidence in these computer models that attempt to simulate a complex world that is beyond current ability to simulate.

[iNow]

There is a lot more to this article - none of which indicates confidence in these computer models that attempt to simulate a complex world that is beyond current ability to simulate.

 

I presume you are preparing a list of perhaps 3 or 4 models which had errors, and will ignore the other hundred models which don't. Just guessing here.

 

 

Here's quite an extensive and well referenced list of retorts to the "models are wrong" claims:

 

http://www.realclimate.org/index.php/archives/category/climate-science/climate-modelling/

 

 

Cite a specific model. We can talk about that. Be transparent with what you're doing if it's so sincere.

[JohnB]

The scenario that has the ~0.34 ºC increase is scenario A, which has an exponentially increasing radiative forcing. Since those conditions were not present in the 90's, it's dishonest to characterize that as Hansen's prediction.

We have covered this before.

 

To again quote from Hansen 1988:

Scenario A assumes that the growth rate of trace gas emissions typical of the 1970s and 1980s will continue indefinitely; the assumed annual growth rate averages about 1.5% of current emissions, so the net greenhouse forcing increases exponentially.

Scenario B has decreasing trace gas growth rates, such that the annual increase of the greenhouse climate forcing remains approximately constant at the present level.

The inputs for scenario A are closest to reality, but the graph for scenario B is closest to reality. It's not enough to get the right output, you have to have the right input as well. Hansens 1988 paper was flawed in that it either did not correctly model the forcings resulting from an increase in GHGs or it did not correctly model the temp response resulting from those forcings.

 

BTW, Hansen has a paper in preprint where he puts the Climate Sensitivity at 6⁰ for doubled CO2.

Comparing mesoscale atmospheric models to GCMs is comparing apples to oranges

So I can assume from that I can safely discount the next article I read that says "Warming/Cooling of (Region of your choice) is consistent with model predictions" as b*llshit?

[SkepticLance]

To iNow

 

You gotta do better than that!

 

The first sentence of paragraph 2 in your reference says ...

 

"The uncertainties in the impacts of rising greenhouse gases on multiple systems are significant"

 

In other words, even Realclimate admits that computer models of global climate are not accurate. And the reason, as I have said so many times before, is that they cannot take into account all the unknown variables.

 

Freeman Dyson puts it this way ...

 

"The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand."

 

You are fighting a losing battle, iNow. I doubt that anyone else participating in, or merely reading, this thread believes, as you seem to, that these computer models are some kind of gospel.

[iNow]

I doubt that anyone else participating in, or merely reading, this thread believes, as you seem to, that these computer models are some kind of gospel.

 

I dare not say strawman? If you think my argument is that the models are gospel, then you're seriously and significantly deluded. I'd quite appreciate it if you'd focus your attention on specific data and stop trying to paint me as some enviro-religious fundie. I'd quite have cracked your skull by now if you were in the same room as me, but alas, I'm forced to punch you with my words within this psyber venue which we co-occupy.

[bascule]

"The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand."

 

These sort of things are being added in the form of modules developed by other research groups which are incorporated into a larger overall model.

 

You are fighting a losing battle, iNow. I doubt that anyone else participating in, or merely reading, this thread believes, as you seem to, that these computer models are some kind of gospel.

 

To move past silly strawmen, do you think historical climate reconstructions are suspect, particularly those of the past 100 years?

[SkepticLance]

To Bascule

 

In a previous thread, you posted a series of graphs showing those historical reconstructions. Most were reasonably close to historical reality. A couple were significantly askew by comparison. Does this answer your question?

 

To iNow

 

Please keep the strawman verbiage out of it. If you think I misunderstand your position, feel free to describe exactly what your position is, so that we can discuss matters without misunderstanding.

[swansont]

We have covered this before.

 

To again quote from Hansen 1988:

Scenario A assumes that the growth rate of trace gas emissions typical of the 1970s and 1980s will continue indefinitely; the assumed annual growth rate averages about 1.5% of current emissions, so the net greenhouse forcing increases exponentially.

Scenario B has decreasing trace gas growth rates, such that the annual increase of the greenhouse climate forcing remains approximately constant at the present level.

The inputs for scenario A are closest to reality, but the graph for scenario B is closest to reality. It's not enough to get the right output, you have to have the right input as well. Hansens 1988 paper was flawed in that it either did not correctly model the forcings resulting from an increase in GHGs or it did not correctly model the temp response resulting from those forcings.

 

You've claimed this before, here in post 37, but were rebutted in post 46 by ChrisC.

 

 

This seems to show a decreasing slope of emissions rate in the 1990's.

 

Were the forcing increasing exponentially or linearly? Do you have a cite that shows an exponential increase of the forcings?

[bascule]

In a previous thread, you posted a series of graphs showing those historical reconstructions. Most were reasonably close to historical reality. A couple were significantly askew by comparison. Does this answer your question?

 

If you feel the former is the case, doesn't that mean that computer models are reasonably reliable at reconstructing the recent historical climate? (i.e. past 100 years)

[SkepticLance]

To Bascule

 

What do you mean by 'reasonably reliable?' I have said, several times, that my own prediction for the future is a continuation of the current situation. Warming of 0.18 Celsius per decade plus or minus a bit, and a sea level rise of 3 mm per year plus or minus a bit, until about 20 years after humans manage to control carbon emissions.

 

In my opinion 'reasonably reliable' means a computer model that is able to come up with predictions that are appreciably better than the prediction I just gave. Mine was based on a continuation of the current situation. The models you rank so highly must be able to be substantially better than my predictions, or else what value are they?

[iNow]

I have said, several times, that my own prediction for the future is a continuation of the current situation. Warming of 0.18 Celsius per decade plus or minus a bit, and a sea level rise of 3 mm per year plus or minus a bit, until about 20 years after humans manage to control carbon emissions.

And, Lance, you've also been shown several times how the change is not linear, so a conclusion such as yours appears to have no solid foundation on which to stand.

[JohnB]

You've claimed this before, here in post 37, but were rebutted in post 46 by ChrisC.

Which I rebutted in post 50. (Using an independent resource rather than a blog too.)

The EIA:

World carbon dioxide emissions are expected to increase by 1.9 percent annually between 2001 and 2025.

Hansen 1988:

Scenario A assumes that the growth rate of trace gas emissions typical of the 1970s and 1980s will continue indefinitely; the assumed annual growth rate averages about 1.5% of current emissions, so the net greenhouse forcing increases exponentially.

(Emphasis mine)

Mauna Loa:

From a UK govt report.

Between 1990 and 2003, global carbon dioxide emissions have grown by 20 per cent, according to figures from the IEA.

Which is about 1.5% annually.

 

Hansen Scenario A assumed a growth rate of 1.5% and that is what the data shows happened, yet the graph for "A" was wrong. This leads me to conclude the model "either did not correctly model the forcings resulting from an increase in GHGs or it did not correctly model the temp response resulting from those forcings." In a nutshell it would appear that Hansen 1988 got the Forcings-> Temperature rise right, but the GHG increase -> Forcings equations wrong. (The RC piece BTW only concerned itself with the forcings part of the model and does not mention at all, the GHG increase assumptions.

Do you have a cite that shows an exponential increase of the forcings?

I didn't say that the forcings would increase exponentially with an annual emissions increase of 1.5%, Hansen did. If an annual 1.5% emissions increase did not result in an exponential increase in forcings then the fault lies in the model, not with me.

 

Put simply. Hansen 1988 Scenario A assumed a 1.5% annual increase would result in an exponential forcing giving rise to Graph Line A. The observed increase matched the assumption, but the forcing was roughly linear, not exponential, so giving Graph Line B. Hence there is a flaw in the way the model handles the GHG-> Forcing relationship. That's really all I'm getting at.

 

As an aside, the UK report above also says;

The growth in carbon dioxide emissions has been particularly rapid in the last fifty years, though the rate of increase has slowed to some extent in the last two decades.

So it's still at 1.5%/year but has declined. Presumably it was higher than 1.5%/year in the 70s-80s. Almost seems contradictory.

[iNow]

Which I rebutted in post 50. (Using an independent resource rather than a blog too.)

John,

 

I've debated with you before, and I know you are better than a misrepresentation like that. The blog (RealClimate.org) is run by multiple climate scientists, and each of the claims they make within are supported using independent and peer reviewed sources. Let's not mischaracterize and dismiss the data because of the venue in which it was shared.

 

http://www.realclimate.org/index.php?p=447

 

 

Again, I see several peer reviewed sources within, as well as information from people who are very well trained in the topic under discussion.

 

Also, your post above about scenario A in the Hansen 1988 paper implies that there were not other scenarios considered.

 

 

Be well.

 

 

 

 

 

 

Hansen's scenario B (not A) turned out to be the most accurate emission scenario, and got the corresponding warming right well within the uncertainty range. RC had a post on this (http://www.realclimate.org/index.php?p=447 ). I've went back to the original paper, and I see no faults with the RC piece.

 

The citation of the first paper is just intellectual dishonesty. Another one that RC tore apart not too long ago. Personally, I'm only a few years removed from "boy who cried wolf" stories which is why I don't bother wasting my time with Christy and Soon and Baliunas and Roy Spencer, etc. Too much literature to read, not enough time for the BS.

 

The second paper should not be taken as a denialist paper. It claims that CO2 causes warming, but has a low sensitivity. The problem is the simple 1-box model used by schwartz which gives the climate one characteristic timescale to respond (i.e., he assumed that the oceans will respond as quick as land and the atmosphere). He says that it is a very simple model himself, but there is a slight irony in the blogosphere when it comes to the complicated GCM's (like the IPCC graph someone is throwing around) that all fail, but the simple models that say "not as much CO2 effect" that are now the gospel truth.

[swansont]

Hansen Scenario A assumed a growth rate of 1.5% and that is what the data shows happened, yet the graph for "A" was wrong. This leads me to conclude the model "either did not correctly model the forcings resulting from an increase in GHGs or it did not correctly model the temp response resulting from those forcings." In a nutshell it would appear that Hansen 1988 got the Forcings-> Temperature rise right, but the GHG increase -> Forcings equations wrong. (The RC piece BTW only concerned itself with the forcings part of the model and does not mention at all, the GHG increase assumptions.

 

I didn't say that the forcings would increase exponentially with an annual emissions increase of 1.5%, Hansen did. If an annual 1.5% emissions increase did not result in an exponential increase in forcings then the fault lies in the model, not with me.

 

Put simply. Hansen 1988 Scenario A assumed a 1.5% annual increase would result in an exponential forcing giving rise to Graph Line A. The observed increase matched the assumption, but the forcing was roughly linear, not exponential, so giving Graph Line B. Hence there is a flaw in the way the model handles the GHG-> Forcing relationship. That's really all I'm getting at.

 

As an aside, the UK report above also says;

 

So it's still at 1.5%/year but has declined. Presumably it was higher than 1.5%/year in the 70s-80s. Almost seems contradictory.

 

 

OK, thanks for clearing that up. I agree — the forcing tied to temperature increase fits scenario B, but the emissions converting to concentration and forcings doesn't work. The Mauna Loa numbers are increasing by about 0.4% a year.

 

I'm not familiar enough with the model to know how separable the two issues are, but my naive assumption is that they are. The number that gets discussed often is the climate sensitivity, which is dependent on atmospheric concentration.

 

Anyone know where all the "missing" CO2 is?

[bascule]

In my opinion 'reasonably reliable' means a computer model that is able to come up with predictions that are appreciably better than the prediction I just gave. Mine was based on a continuation of the current situation. The models you rank so highly must be able to be substantially better than my predictions, or else what value are they?

 

The value is in diagnosing the nature of the Earth's radiative imbalance based on historical reconstructions, as I just went over with you.

[SkepticLance]

iNow said :

 

"And, Lance, you've also been shown several times how the change is not linear, so a conclusion such as yours appears to have no solid foundation on which to stand."

 

This was in relation to my own prediction of future climate change. The first thing you need to understand, iNow, is that I am a true sceptic. I am sceptical of my own predictions as well as others! I suggest a continued warming and sea level rise at roughly the same as today. If this happens in spite of the non linear relationship between CO2 and warming, it is because the rate of CO2 emission increases - non linear. With the way China is going, that seems a real possibility.

 

However, I do not really take my own predictions very seriously. I think they are more likely than the computer models, but that is not much of a recommendation!

[bascule]

This was in relation to my own prediction of future climate change. The first thing you need to understand, iNow, is that I am a true sceptic. I am sceptical of my own predictions as well as others! I suggest a continued warming and sea level rise at roughly the same as today. If this happens in spite of the non linear relationship between CO2 and warming, it is because the rate of CO2 emission increases - non linear. With the way China is going, that seems a real possibility.

 

However, I do not really take my own predictions very seriously. I think they are more likely than the computer models, but that is not much of a recommendation!

 

So not only are climate scientists wrong, but your conclusions garnered through static analysis are more likely than the conclusions of scientists which are the culmination of decades of research and modeling...

 

WTF Lance, do you just hate climate science?

[SkepticLance]

To Bascule

 

I love science of all kinds.

However, I think a lot of people, including your no doubt worthy self, tend to ascribe greater knowledge to climatology than actually exists.

 

This morning I was reading an article in New Scientist (Australian printed version, 3 May, page 8) titled 'We need better forecasts - and fast.' New Scientist has an editor who has shown himself in editorials to be a global warming catastrophist. So this article is not one favouring people of my bent.

 

It starts by quoting Tim Palmer, climate modeller at the European Centre for Medium-Range Weather Forecasts at Reading UK.

"Politicians seem to think the science is a done deal. I don't want to undermine the IPCC, but the forecasts, especially for regional climate change, are immensely uncertain."

 

Later in the article, it says

" On top of this, some climate scientists believe that even the IPCCs global forecasts leave much to be desired."

 

Of course, since the editor is such a believer in catastrophe, the tone of the article is that, if climate models are so unreliable, then the true situation is likely to be much worse. They show little or no evidence for why it should be worse, and not better, but if you are biased to alarmism, then that is what you write.

 

The point I am making is that even alarmists like the New Scientist writers appreciate that climate models are unreliable, whether local or global in nature.