This is something I never expected to see in print. Climate modeler Dr. Gavin Schmidt of NASA GISS comments on the failure of models to match real world observations.
Source:
[ http://twitter.com/ClimateOfGavin/status/340605947883962368 ]
While the discussion was about social models, it is also germane to climate modeling since they too don’t match real world observations. Below is an example of climate models -vs- the real world; something’s clearly not right.
Graph source: IPCC AR5 draft
Is it maths or assumptions (or both) that cause the divergence?
UPDATE: In comments, I had a discussion with reader “jfk” which I think is worth sharing. He made some good points, and it helped hone my own thinking on the issue:
jfk says: Submitted on 2013/06/01 at 8:40 am
Well, I still think it’s a bit unfair to Gavin (and I am no fan of his). But hey, it’s Anthony’s site.
For a good review of the many failures of statistical modeling in social sciences (and one or two successes) see the book “Statistical Models: Theory and Practice” by David Freedman. Whether or not climate modeling has devolved to the point where it is social science rather than physics, well, I hope it’s not quite that bad…
REPLY: And I think it is more than a bit unfair to us, that if he believes what he tweets, he should re-examine his own assumptions about climate modeling. We have economies, taxes, livelihood, etc. hinging (or perhaps failing) on the success of these models to predict the climate in the future. The models aren’t working, and Dr. Schmidt knows this. Unfortunately his job is tied to the idea that they do in fact work. I feel no regrets at making this comparison front and center. – Anthony
UPDATE2: RussR in comments, provides this graph below showing Hansen’s modeled scenarios against real world observations. He writes:
Here’s an excel spreadsheet comparing observed temperatures vs. model projection from: Hansen (1988), IPCC FAR (1990), IPCC SAR (1995) and IPCC TAR (2001), in pretty charts.
It can be updated as more observations are added.
https://dl.dropboxusercontent.com/u/78507292/Climate%20Models.xlsx
UPDATE3: Dr. Roger Pielke Sr. adds this in comments.
Climate models are engineering code with quite a few tunable parameters, and fitting functions in their parameterization of clouds, precipitation, land-atmospheric interfacial fluxes, long- and short-wave radiative flux divergences, etc. Only a part of these models are basic physics representations – the pressure gradient force, advection, the Coriolis effect.
The tunable parameters and fitting functions are developed by adjustment from real world data and a higher resolution models (which themselves are engineering code), but only for a quite small subset of real world conditions.
I discuss this issue in depth in my book
Pielke Sr, R.A., 2013: Mesoscale meteorological modeling. 3rd Edition, Academic Press, in press. http://www.amazon.com/Mesoscale-Meteorological-Modeling-International-Geophysics/dp/0123852374/ref=sr_1_2?ie=UTF8&qid=1370191013&sr=8-2&keywords=mesoscale+meteorological+modeling
The multi-decadal global climate model projections, when run in a hindcast mode for the last several decades are showing very substantial errors, as I summarize in the article
http://pielkeclimatesci.files.wordpress.com/2013/05/b-18preface.pdf
Rocky Road–
No because the purpose of theories and models in the social sciences is not to reflect reality but to change it. The theory or model exist to gain implementation to change behaviors. That’s the purpose.
It is also why you hear the phrase Best Practices so often. It is a practice that can change human behavior in desired directions if Statism is your goal.
Here is another peer reviewed study stating that CO2 is not responsible for global warming.
How many more years will it take for Gavin Schmidt to admit he was wrong regarding his CO2/T conjecture? Will he ever admit that he was wrong?
Russ R. says:
June 1, 2013 at 10:12 am
Nice spreadsheet! Thanks.
Russ R.-
“Here’s an excel spreadsheet comparing observed temperatures vs. model projection from: Hansen (1988)”
Thanks for the excel sheet. Very handy to have the ever-failing predictions and the most grossly tampered observations in one place.
There is an interesting trend in Hansen’s 1988 scenario C. The CO2 emissions are zeroed out after 2000. The interesting detail is that his model predicts that temperature rises another 0.1 – 0.2 C or so before it stabilizes after 5 – 10 years.
There is precious little dead-certain heat in the pipeline in the 1988 model.
It is also interesting that measured temperatures are below scenario C, which Hansen claimed was ‘safe.’ Steven Goddard made this point a few months ago.
@ur momisugly Russ R. and Anthony–
This is a very good comparison of the model predictions of successive IPCC reports vs. reality. (If, in fact, GISTEMP is at all close to reality).
I wonder if Russ R. would consider writing this up as a post for WUWT. As you say, it would need updating to the later IPCC reports.
The diagram (a) on the IPCC 2001 sheet needs some explanation. I get that the x-axis is different models and the circles are the high-medium-low estimates of IPCC 2001 but the rest of the symbols are somewhat puzzling.
The one thing still needed is to highlight the prediction/projection that followed most closely the actual increase of GHG. (You could, for example, embolden that curve.) Then we would see that in most cases, it was the highest projection that the IPCC predicted that was closest to the true GHG increase. This makes the failure of their projections even more apparent. A single high-information high-impact graph could be prepared with just their single predictions closest to the true scenario vs actual temperature. The weakness of the Glickstein graph is that he chose their middle predictions to compare to the temperatures rather than those that matched most closely the scenarios. This allowed the alarmists to say that the observed values were still within the uncertainty bands. The better graph proposed here, anchored in the reality of the scenarios, would remove that argument.
Robin says:
“Rocky Road–
No because the purpose of theories and models in the social sciences is not to reflect reality but to change it. The theory or model exist to gain implementation to change behaviors. That’s the purpose.
It is also why you hear the phrase Best Practices so often. It is a practice that can change human behavior in desired directions if Statism is your goal.
”
Which _exactly_ why climate science is closer to a social science than a hard science.
At least one model, UCAR’s CAM 5, uses a “dry water” instead of a real one: it neglects a temperature dependence of a latent heat of evaporation of water. That causes an approximately 3% error in a calculation of a heat transfer by an evaporation of water from tropical seas. That happens in each step of an iterative computation.
Apology to Richard Feynman, who used a term “dry water” for a physical description neglecting a viscosity.
Lance Wallace says:
June 1, 2013 at 10:14 am
Sorry, I had refreshed and still saw “Climate” for some reason; now, I don’t see it. I apologize to Anthony.
The title has changed but the URL has not. I also thought the title was unchanged after glancing at the address box.
The gravy train is now running so slow that even stalwarts of AGW are leaping off it.
Gavin is right in this case, in the social sciences and maybe also in climate science, most of the calculations are perfect.
No such thing. If the calculations are perfect then it’s the arithmatic that is correct. you know, 2+2=4. Sadly, in science that is a total and utter nonsense.
Schmidt has no way of knowing that the arithmetics are correct because he cannot and never has vVV&T’d his model(s).
[snip – off topic slayers junk science -mod]
I am growing in my respect for Gavin. It is understandable that he would be highly defensive and unwilling to yield easily, but, as far as I am concerned, all will be forgiven if he mans up over the next few years and admits that the models were overstated and conclusions overdrawn. I think he is starting to reconsider. It would take a lot to lay your life’s work on the altar, particularly when he helped set up a propaganda site for the cause. I have always thought, in spite of those facts, that he makes an attempt to be fair quite often. If he recognizes the errors and turns from them, he proves himself to be a true scientist. Then again, it may turn out that he has basically been right and the 17 year pause we are in is just an anomaly that is quickly erased as the temperatures shoot up…..i doubt it, but it is possible.
Rings a bell:
“If the administration knew about the problems and chose not to prevent them, then clearly something is rotten in the state of modeling”
That SAR models graph isn’t looking too bad.
WRT jfk’s comment highlighted by Mr Watts. I’m sure that most people are like myself, that they do not expect perfection from science and that it can be a messy business at times. I would never expect climate modeling to be highly accurate, based on my own understanding of the current science.
The thing is, it is the scientists themselves that have been claiming the accuracy of their models for many years now. They have failed to show proper humility. We now have these IPCC conferences where a bunch of them endeavour to pressure the rest of the world to re-engineer, from the top down, the entire world economy, based primarily but not entirely on these models.
It is not the failure of statistical modeling that is the underlying issue. It is the failure of the majority of scientists, and of world leaders, to acknowledge the weakness in climate models. Without the cabal of global warming alarmists and the IPCC, nobody would be highlighting comments like these from individuals like Gavin Schmidt.
Mr Watts is doing us all a service by doing so.
“The same issues applies to climate models.”
Says you, Anthony.
I highly doubt Gavin would have made such a statement about climate models and if you read the comments here it is very clear that your readers think he was talking about climate.
REPLY: So, you are saying that if bad assumptions are used to create initial conditions and process dynamics for climate models, and the mathematics are right, that the climate models will still give the right answer? Do tell. – Anthony
Ryan says:
June 1, 2013 at 11:58 am
““The same issues applies to climate models.”
Says you, Anthony.
I highly doubt Gavin would have made such a statement about climate models and if you read the comments here it is very clear that your readers think he was talking about climate.”
No, Ryan. We have understood it. Please try reading our comments again and with less haste.
Mark in Montreal says:
June 1, 2013 at 11:08 am
“I am growing in my respect for Gavin. It is understandable that he would be highly defensive and unwilling to yield easily, but, as far as I am concerned, all will be forgiven if he mans up over the next few years and admits that the models were overstated and conclusions overdrawn. ”
Standards vary. I find the behaviour of the IPCC climate modelers entirely inexcusable for years now. And no, waiting a few more years until gavin goes into retirement will not do it.
The omissions they have in their models totally discredit them, remember these are attempts at iteratively modeling a chaotic system which is all but impossible even when you have the physics correct. Which they don’t. Yet they have the chutzpah to run their models for thousands of years.
They know very well that their models are parameterized in such a way that they simply confirm the underlying assumption of CO2 driving up temperatures; a hugely complicated machinery that hides the fact that it is all basically curve fitting.
They are therefore not scientists, but crooks, and should be fired on the spot.
Totally fair to make the connection. Gavin probably doesn’t realize the implication on his own, so making the connection for him is a service for us all.
These guys must be praying for warming by now! (Bad form for atheists).
Kurt in Switzerland
No they’re probably praying for another stratospheric eruption. That way the models will have the illusion of giving the right answer again and they can try to waffle about the last 17 years just being temporary departure from a model that is basically correct.
http://climategrog.wordpress.com/?attachment_id=280
1883 1902 1912 1963 1982 1991
since most of those dates seem to fall on a 9 year grid , I’m guessing we will have a major event around 2018.
Greg Goodman (June 1, 2013 at 10:04 am) wrote:
“what also comes as a surprise is that this relationship implies there is a relationship between these variations in climate and the timing of major volcanic events. Now that merits further study.”
Certainly it does merit further study, but it’s not a good sign if it comes as a surprise.
Let’s give credit where it’s due:
Ulric Lyons has been directing attention towards this for years.
Years later along comes a different messenger with the same message and the new messenger is hailed by wuwt readers as a hero. Frankly: Too funny.
This clarifies and acutely emphasizes that the readership here overwhelmingly bases trust on messenger rather than message.
Tip for anyone looking into this: You can get well ahead the new messenger if you just go back and pay attention to what Ulric Lyons & Piers Corbyn have been saying for years.
I saw a claim regarding a paper on Hockeyschtick that Co2 levels were ~425 ppm about 12,750 years ago. Is this correct? If so then talk of highest co2 in millions of years can be called into question???
Abstract – 15 May 2013
Stomatal proxy record of CO2 concentrations from the last termination suggests an important role for CO2 at climate change transitions
See Fig. 7
http://dx.doi.org/10.1016/j.quascirev.2013.02.003
http://ars.els-cdn.com/content/image/1-s2.0-S0277379113000553-gr7.jpg
What a laugh for us at them if there’s a severe temperature drop by 2015.
“Here’s an excel spreadsheet comparing observed temperatures vs. model projection from:”
Divergence from model projections is more than is shown by the GISTEMP plotted. Based on pundits of Global Warming having a: failed to compensate for UIH, b: biased averaged “corrected” temperatures higher, and c: cherry picked and lemon picked weather stations to use in averaging. Thus, actual average global temperatures for recent Alarmist “warm years” are 0.2 to 0.4 C cooler than claimed by Global Warmers.
Nothing happens in the U.S. as far as treaties without 2/3 of the U.S Senate approval. Last vote in 1997 was 95 to 0 against destroying the U.S. economy to save the planet. They may be stupid liberals, but they’re not crazy.