Models: some are good, some are not so good, some are useless.
To conclude, climate models can and have been verified against observations in a property that is most important for many users: the regional trends. This verification shows that many large-scale features of climate change are being simulated correctly, but smaller-scale observed trends are in the tails of the ensemble more often than predicted by chance fluctuations. The CMIP5 multi-model ensemble can therefore not be used as a probability forecast for future climate. We have to present the useful climate information in climate model ensembles in other ways until these problems have been resolved.
From http://www.realclimate.org/index.php/archives/2013/04/verification-of-regional-model-trends/
h/t to Steve Mosher
See also: http://www.gfdl.noaa.gov/cms-filesystem-action/user_files/tk/knutson_et_al_regional_trends_jan2013.pdf
It must have been hard work denying the patently bleedin obvious for so long.
GC models were known GIGO even before major discoveries in climatology of the past 16 years such as the PDO, AMO & fact that TSI may not change much but its spectral composition does, significantly so, none of which new information do they take into account. Besides which, critical assumptions upon which they were & (disgracefully) still are based, like water vapor feedback, have been shown false.
Even if the model outputs matched the observations, this would still not tell us that the models were correct, since in a complex algorithm an error in one parameter can be balanced by an offsetting error in another.
If the model outputs do not match the observations, on the other hand, we can confirm that they are incorrect.
And since they know those models to be incorrect, why are they still trying to use them to ‘present the useful climate information’ when the models do not contain any actual useful information?
If the models can’t be used to forecast future climate, how are they still “useful” — as propaganda tools? Maybe these modern-day oracles should go back to reading animal entrails. It could be done a lot cheaper, and the accuracy would be just as good.
They continue to live in an imaginary model kingdom, even their initial sentence is total fantasy.
Mmm … I haven’t seen any evidence for this at all. Quite the reverse, climate models are well known for being poor at hindcasting regional temperature trends, and as Koutsoyiannis showed, they are totally useless for hindcasting regional precipitation trends.
They are all generally passable at hindcasting the global average surface air temperature trends … but then since they are all generally trained to reproduce historical global average surface air trends, this is meaningless.
So while their admission is welcome and surprising, they still have a long ways to go.
w.
“We have to present the useful climate information in climate model ensembles in other ways”
Sounds like they are trying to hide the decline.
Smacks of classic misdirection. Admit failure, but confine it to a minimalist concept.
Easy solution RealClimate; crowd source the model and make the model open code!
Far more complex systems have been successfully improved by open code. This particular statement though is a bit of misdirection itself; there has not been any project as complex as a full atmospheric/solar/hydro/oceanographic model would truly require. So don’t expect miracles; especially miracles like predicting climate years into the future.
milodonharlani says:
April 15, 2013 at 9:58 am
GC models were known GIGO even before major discoveries in climatology of the past 16 years such as the PDO, AMO & fact that TSI may not change much but its spectral composition does
There is no evidence for long-term changes in spectral composition. There may be such change within each solar cycle, although this is not firmly established yet and some models do incorporate that [and find only minimal impact – less than a tenth of a degree or so], e.g. http://lasp.colorado.edu/sorce/news/2011ScienceMeeting/docs/presentations/6b_Cahalan_Sedona_9-15-2011.pdf
“smaller-scale observed trends are in the tails of the ensemble more often than predicted by chance fluctuations”
Assigning undue credibility to such models flawed in this respect would lead directly to forecasts of increasing frequency of occurrence of extremes of weather.
The alarmists may not realize it, but this admission is fatal to their most recent claims – that anthropogenic climate change will lead to more extreme weather.
The ‘decline’ to hide now is in their credibility.
It is not necessarily good news that regional climate variation is hard to predict. I would even venture that it might not be news at all.
Darn, I was hoping all the modeling/simulations/projections or what ever we want to call the output of the “CMIP5 multi-model ensemble” would be of some benefit/value for my near term (2-5 years) decision making. Basically what climate change should plan for in my area. My test vineyard indicates that if the temperature increases just a tad in the future I should plant more Chardonnay. If the 14 year average temperature (and the monthly SD) stays about the same as it has been for the last fourteen years then I should stick with Zinfandel or Syrah. Oh well, maybe the next effort will be able to provide some data I can actually use.
The CMIP5 multi-model ensemble can therefore not be used as a probability forecast for future climate. We have to present the useful climate information in climate model ensembles in other ways until these problems have been resolved.
That is a good step forward.
To conclude, climate models can and have been verified against observations in a property that is most important for many users: the regional trends.
That isn’t.
Realclimate point out shortcomings wiith models – again – and explain what there is confidence about regarding then and what there isn’t. The post is fairly informative for laypeople. This is spun into an ‘admission’ at WUWT and commenters fire potshots from the trenches into the foggy air.
Pope retains denomination.
Tony, your credibility remains unchanged! Keep up the good work!
Has Pielke, Sr., been able to rescue your “game-changing paper” yet?
Time’s a wasting. Since he’s given up posting to his own blog, that must leave him a lot of time to help you out.
So what’s taking so long? …both he and you have been remarkably silent for a pretty long time, about your “game-changing paper.”
I know…it’s just getting longer and longer and better and better. Forget about the basic, elementary, fundamental, fatal flaw.
Keep up the good work!
Computer models of climate can’t be tested against an erratic global system with time scales that vary on the millenial, century and decadal. If aerodynamic engineers use computer models to their advantage then good for them.
The climate of east North America has been mixed deciduous forest since the end of the last glaciation. Tropical climates have not changed significantly on any biological time scale. The Antarctic climate has not changed since humans found it, but likely it’s been an ice cap for millions of years.
The northern boreal forests and tundra may or may not be slowly recovering (warming) from the little ice age. Sea levels have not changed significantly since the Minoans docked their fishing boats.
Carbon dioxide does not accumulate in the atmosphere. The biological carbon sources and sinks exchange CO2 through the atmosphere at a rate about 33 to 40 times the fossil fuel combustion rates. Oceans hold thousands of times more thermal energy than the air above it. The IPCC is a political entity. “Scientific” organizations exist soley to promote themselves.
Even today, there exists no methodically placed global network of surface weather stations maintained with scientific standards.
There are many more reasons why the AGW issue will be judged by history as a human disgrace.
Shelama says: April 15, 2013 at 10:34 am [snip]
Shelama is trolling – Mods, where are you? 🙂
Meanwhile, any little admission of this kind over at RC is welcome, but why do I suspect their motives?
To conclude, Ptolemy’s System of Epicycles can and have been verified against observations in a property that is most important for many users: the orbits of the Moon, the Sun, Mercury and Venus. This verification shows that many large-scale features of Planetary Orbits are being simulated correctly, but smaller-scale observed trends are in the tails of the ensemble more often than predicted by chance fluctuations. The System of Epicycles can therefore not be used as a probability forecast for the orbits of Mars, Jupiter, or Saturn. (Mars might prove to be just swamp gas.) We have to present the useful orbital information in the System of Epicycles in other ways until these problems have been resolved.
Shelama and barry, sitting in a tree, T-R-O-L-I-N-G!!!
I’ll get my hat ………
“many large-scale features of climate change are being simulated correctly”
Yes. The models are correctly simulating that the world has a climate. And to their credit, none of the models predicted that we would be invaded by zombies from Outer Space. The models have been proved completely correct in that regard, so far.
So congratulations to all the modellers.
“. . . the useful climate information in climate model ensembles . . . ”
Well, that should be a short statement.
~~~~~~~~~~~~~~~~~~~~~~~~
kakatoa says:
April 15, 2013 at 10:23 am
“ . . . in the future I should plant more . . . ”
May I suggest Concord – it is very cold hardy.
@James Baldwin Evans says:
April 15, 2013 at 11:25 am
Laugh!
You have penetrated the collective mind of the “Climate Scientist” and seen its simple pleasures. Play-time!
Hire a supermodel?
The above quotation sound to me nothing more than trying to draw attention away from demonstrable failure. With the intention of reformating to make the same claims.
kakatoa says:
April 15, 2013 at 10:23 am
If you happen to need taste testers for the Zinfandel let me know. No special qualifications only lots of tasting of product.
James Evans says:
April 15, 2013 at 11:25 am
How well do they do on seasons? Or is that just weather?