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
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Nice thread – better than many I have seen here.
I think that the topic of what is wrong with general circulation models has to be preceded by a conversation about what is right with them. They are far better constrained than economic or social models are.
I think we are finding out that the deeper layers of the ocean are taking up a lot of the heat imbalance. This means that the rate of change of surface temperature is lower than expected, which is good news. But it does NOT mean the equilibrium sensitivity is lower than expected, which leaves us still in a difficult spot. First, sea level rise and ocean acidification are unabated. Also, the final outcome remains a dramatically changed planet, especially if we continue to use all available fuels. The good news seems to be only that it will take us longer to get there.
I admire garymount’s efforts, but I think he has a long way to go. The combinatorial explosion to which he refers is moot because the system and its models operate under a varierty of global constraints (conservation laws). This is what makes climate modeling possible to the extent that it is possible. Again it is probably best to begin by determining what is possible before determining what is impossible.
But the bottom line is still Steven Schneider’s: “You can’t add four watts per square meter to this system and expect to have nothing happen.” Whether the science is solid or not, the risk remains real. Things are changing rapidly. Whether global mean surface temperature changes rapidly or not doesn’t settle very much about where we are heading.
I hate to divert attention from the exact topic but I would like to point out that Milton Friedman once argued that it did not matter how unrealistic the premises were as long as the predictions of the models were acceptable. I wonder how many of our Monetarist friends who are correct to attack the climate models do not have the moral courage and consistency to do the same to their own assumptions and models.
commieBob said @ur momisugly June 2, 2013 at 3:04 pm
The ad hoc explanation for Neptune’s apparently errant orbit was the existence of another planetary body that was duly discovered where Newton’s Law said it must be: Pluto. Belief in naive falsification would have greatly impeded this discovery.
What makes you think that Newton’s Law does not apply to Neptune? Have you been imbibing too much Myrrh?
mtobis, I’m curious which planet you live on.
No, we’re not finding that out. Someone has theorized it. There is no actual evidence, just a belief.
Sea level rise is where it has been since anyone ever tried to measure it. There is no increase. There are decreases. And the whole “acidification” thing is a load of BS. Let’s see some proof before you start spouting this stuff.
No, they’re not. Things are staying the way they were, rapidly.
It’s this sort of post that makes people laugh at alarmists. You just threw in a bunch of unsupported and incorrect assertions as though they were facts. They are not.
mtobis wrote: “You can’t add four watts per square meter to this system and expect to have nothing happen.”
++++++++
I’ve heard this claim before and it really bothers me the way people talk about the “theoretical” effect of CO2 such that it increases surface temperature by adding energy to our planet. How can something that has no energy, contribute energy to a system? And CO2 is not an energy source and can not be modeled as such, I think.
When people start to assume that CO2 is an energy source, all sorts of nonsense follows.
SOMEONE here help me out and set me straight on calling BS here.
Mario
@DirkH
While I enjoyed your comment, please, not the heat-trapper!
I do fully understand the physics of IR absorption and emission, and while the lack of precision may excise you (for which I apologise) it is just short-hand that is sufficiently descriptive and avoids pedantry.
No kidding? Okay, I didn’t know that he was from the UK. Don’t know how I missed that for all these years. Thanks.
P.S. any chance they want him back?
Vangel Vesovski says:
June 2, 2013 at 7:16 pm
“I wonder how many of our Monetarist friends who are correct to attack the climate models ”
Who are those monetarist friends you are talking about?
@DirkH
Who are those monetarist friends you are talking about?
The people on the right who rightfully argue that the assumptions that go into the climate models are unrealistic and as such we should ignore the AGW crowd. I wonder why it is that they can’t understand that many of their financial models suffer from the same problem. They tend to worship Milton Friedman but he argued that unrealistic assumptions did not matter very much because they could still lead to the ‘right’ conclusion.
mtobis (@mtobis) says:
June 2, 2013 at 3:11 pm
“I think that the topic of what is wrong with general circulation models has to be preceded by a conversation about what is right with them. They are far better constrained than economic or social models are.”
That is a fallacy. They are iterative models. They can be right to 99%, and wrong to 1 %; or they can be right to 99.9% and wrong to 0.1% – this only affects the number of timesteps until they go off the rails.
CodeTech says:
June 2, 2013 at 8:16 pm
mtobis, I’m curious which planet you live on.
“First, sea level rise and ocean acidification are unabated. Also, the final outcome remains a dramatically changed planet, especially if we continue to use all available fuels.”
Sea level rise is where it has been since anyone ever tried to measure it. There is no increase. There are decreases.
Really?
http://sealevel.colorado.edu/files/2013_rel4/sl_ns_global.png
And the whole “acidification” thing is a load of BS. Let’s see some proof before you start spouting this stuff.
“Things are changing rapidly.”
No, they’re not. Things are staying the way they were, rapidly.
Like shown in the NOAA sealevel graph?
It’s this sort of post that makes people laugh at alarmists. You just threw in a bunch of unsupported and incorrect assertions as though they were facts. They are not.
That’s exactly what you just did!
mtobis (@mtobis) says:
June 2, 2013 at 3:11 pm
“I think that the topic of what is wrong with general circulation models has to be preceded by a conversation about what is right with them. They are far better constrained than economic or social models are.”
Obviously you are not a modeler and have no idea what you are talking about. Contraining variables never makes a model better by itself because the more variables you constrain the more assumptions you are making. This makes the model further divorced from reality, but sometimes constraining a model is a good thing. We could argue whether this makes climate models better, but the fact remains there are more assumptions made and if even one shows an error of 1%, your model is broken beyong any sort of fixing due to iteration as some other posters mentioned. The thing is, there is no way to determine which variable is wrong if your results are bad.
In my opinion, climate scientists will NEVER find the correct model because their idea on fixing the models involves adding and constraining additional variables when there is a much better chance that one of the earlier assumptions was wrong. This is why as we gather more data, and go longer without warming you will see one of two things happening:
Climate sensitivity due to CO2 will go down.
Or other variables will be added that “dwarf” the CO2 signiture.
There is no other way to account for CO2 not being a driver when the models were programmed as such. And the scientists are so stubborn and arrogant that they will never admit they were completely wrong and will only step down gradually.
Mario Lento says:
June 2, 2013 at 8:57 pm
mtobis wrote: “You can’t add four watts per square meter to this system and expect to have nothing happen.”
++++++++
I’ve heard this claim before and it really bothers me the way people talk about the “theoretical” effect of CO2 such that it increases surface temperature by adding energy to our planet. How can something that has no energy, contribute energy to a system? And CO2 is not an energy source and can not be modeled as such, I think.
When people start to assume that CO2 is an energy source, all sorts of nonsense follows.
SOMEONE here help me out and set me straight on calling BS here.
OK, it’s called ‘feedback’, the sun is the ultimate source, more CO2 results in more energy being fed back which otherwise would leave the planet. Since the sunlight continues the energy reaching the surface increases.
No Pompous, you have it backward. Students (and climate scientists) will invariably misapply any equation but they will do it in a manner that is close enough to being right that one has to work to figure out what, precisely, they have done wrong. That causes the consumption of alcohol.
My light bulb experiment doesn’t invalidate Ohm’s law. It does, however, demonstrate that it gives junk results if there are other factors you haven’t accounted for. Similarly, Einstein didn’t invalidate Newton’s laws of motion. He just re-defined their domain.
Phil, you’re funny.
You posted a graph that shows sea level rise from 1992 as if that proves something, and it’s even deliberately scaled to look alarming. You’ll have to try harder than that. Read what I wrote, since you quoted it.
Do you not understand the word “Alarming”?
Phil. says:
June 3, 2013 at 6:16 am
“OK, it’s called ‘feedback’, the sun is the ultimate source, more CO2 results in more energy being fed back which otherwise would leave the planet. Since the sunlight continues the energy reaching the surface increases.”
And of course, as 50% of the sunlight that hits the “top of the atmosphere” is infrared, more CO2 in the stratosphere leads to more efficient radiative cooling.
@ur momisugly commieBob
I argued against Feynman’s general statement: “one falsification and the theory is falsified forever” by pointing out that a falsification of theory, or law is invariably overcome by an ad hoc explanation. You argued “against” this by providing an example where saving Ohm’s Law requires the ad hoc explanation that electrical resistance varies with temperature, hence my remark about Myrrh. It is logically impossible to support the Feynman quote by providing contradictory examples. If you wish to support Feynman’s statement then you must do so by providing evidence in favour of it.
This has nothing directly to do with students, climastrologists etc; it is a matter of logic and what actually happens in science.
@Phil. says “OK, it’s called ‘feedback’, the sun is the ultimate source, more CO2 results in more energy being fed back which otherwise would leave the planet. Since the sunlight continues the energy reaching the surface increases.”
++++++
Thank you. Yes, I know that’s the theory. But I am a bit skeptical that it’s certain that there is a 4 Watts per meter square of energy that is kept in our system at such a level of CO2 in the atmosphere. That theory is used as if there was a certainty of extra energy, when some would argue that CO2 eventually lets out as much as it keeps in or at least some or most of it eventually escapes –and we do not know for certain that it adds a net amount of energy to our system. I’d say it has some affect, but the jury is still out on how much.
I have no desire whatsoever to defend Feynman’s statement. Any theory, law, or equation is an approximation of reality. Any engineer who loses sight of that will eventually end up in serious deep doo-doo.
A counter-example does not always invalidate a theory. The fact that a cannon ball falls faster than a feather does not invalidate the laws of gravity. It does, however, demonstrate that the laws of gravity do not account for all the factors that may determine how fast a feather falls.
Actually, I have spent a fair portion of my career working with and among scientists. What actually happens in science is quite removed from what most people think actually happens in science. In particular, the vision of the scientist, as an idealistic, dispassionate seeker-of-truth, is mostly wrong. Scientists suffer from biases, cognitive blind-spots and outright stupidity just as much as the rest of us. 🙂 Nobody escapes the human condition*.
Anyway Pompous, we seem to be talking at cross-purposes because I had no idea that the conversation was about Feynman.
============================
*The Human Condition – “the agonising, underlying, core, real question in all of human life, of are humans good or are we possibly the terrible mistake that all the evidence seems to unequivocally indicate we might be?” https://en.wikipedia.org/wiki/Human_condition
DirkH says:
June 3, 2013 at 2:28 pm
And of course, as 50% of the sunlight that hits the “top of the atmosphere” is infrared, more CO2 in the stratosphere leads to more efficient radiative cooling.
+++++++++++++
Thank you DirkH. That is the kind of point I was trying to make. We cannot just assume that CO2 is causing the 90% of warming, 75% of warming or 50% or???… and not responsible for the cooling… or even statistically discernible at all! No one has been able to convince me that we know what the effect of CO2 really is, except those who say probably 1C with each doubling up to a point of severely diminishing returns –hence the logarithmic argument. But that is still not a fact, just a pretty reasonable guess.
I’m sort of excited about the increase of CO2 since we do know that it is needed for life to thrive and non toxic at the levels we will ever see even if it quadruples from 300ppm.