Reader Jimbo advises in WUWT Tips and Notes about something Dr. [Kevin Trenberth] wrote that makes you wonder what he’s talking about when there are so many uses of the word “prediction” in the IPCC AR4. It also makes me wonder what the Economist author Oliver Morton was doing running a blog by Nature. Is there no separation between science journalists and science journals?
Trenberth suggests that after the last report “…the science is settled or done and now is the time for action.”. Here we are six years later, and another IPCC report is coming out on that “settled science” and there is no successor to Kyoto. I wonder how many times the word “prediction” will be used in the upcoming AR5?
Jimbo writes: I stumbled on a quote from [Kevin Trenberth] over at the Nature Blog dated 04 Jun 2007.
Source: http://blogs.nature.com/climatefeedback/2007/06/predictions_of_climate.html
I thought I’d take a look because I was sure I had seen the IPCC use the word ‘predict’.
[My bolding throughout]
This subsection focuses on the few results of initial value predictions made using models that are identical, or very close to, the models used in other chapters of this report for understanding and predicting climate change.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch8s8-4-11.html
—————–
…Some qualitative inconsistencies remain, including the fact that models predict a faster rate of warming in the mid- to upper troposphere which is not observed in either satellite or radiosonde tropospheric temperature records….
…The first IPCC Scientific Assessment in 1990 (IPCC, 1990) concluded that the global mean surface temperature had increased by 0.3 to 0.6°C over the previous 100 years and that the magnitude of this warming was broadly consistent with the predictions of climate models forced by increasing concentra- tions of greenhouse gases. However, it remained to be established that the observed warming (or part of it) could be attributed to the enhanced greenhouse effect. Some of the reasons for this were that there was only limited agreement between model predictions and observations,…
…However, models generally predict an enhanced rate of warming in the mid- to upper troposphere over that at the surface (i.e., a negative lapse-rate feedback on the surface temperature change) whereas observations show mid-tropospheric temperatures warming no faster than surface temperatures….
…..“historical” indicates the signal is taken from a historical hindcast simulation, “future” indicates that the pattern is taken from a prediction……
…Changes in the annual mean surface temperature were found to be highly significant (in agreement with previous results from Hegerl et al., 1996, 1997). The predicted change in the annual cycle of temperature as well as winter means of diurnal temperature range can also be detected in most recent observations….
…Estimation of uncertainty in predictions
The scaling factors derived from optimal detection can also be used to constrain predictions of future climate change resulting from anthropogenic emissions (Allen et al., 2000b). The best guess scaling and uncertainty limits for each component can be applied to the model predictions,……
… An example based on the IS92a (IPCC, 1992) GS scenario (whose exact forcing varies between models, see Chapter 9, Table 9.1 for details) is shown in Figure 12.13 based on a limited number of model simulations. Note that in each case, the original warming predicted by the model lies in the range consistent with the observations….
…The range is significantly less than one (consistent with results from other models), meaning that models forced with greenhouse gases alone significantly overpredict the observed warming signal….
…All but one (CGCM1) of these ranges is consistent with unity. Hence there is little evidence that models are systematically over- or under- predicting the amplitude of the observed response/ under the assumption that model-simulated GS signals and internal variability are an adequate representation (i.e. that natural forcing has had little net impact on this diagnostic)….
…Original model prediction under IS92a greenhouse+sulphate forcing…
…The SAR predicted an increase in the anthropogenic contri-bution to global mean temperature of slightly over 0.1°C in the five years following the SAR, which is consistent with the observed change since the SAR (Chapter 2). The predicted increase in the anthropogenic signal (and the observed change) are small compared to natural variability, so it is not possible to distinguish an anthropogenic signal from natural variability on five year time-scales….
http://www.ipcc.ch/ipccreports/tar/wg1/pdf/TAR-12.PDF
——————-
…During the early summer season, October to December, both models predict drying over the tropical western side of the continent, responding to the increase in high-pressure systems entering from the west, with MM5 indicating that the drying extends further south and PRECIS further east….
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch11s11-2-3-2.html
——————-
…The IPCC commissioned a Special Report on Emissions Scenarios (SRES). Four “marker scenarios” representing different world storylines are used to estimate emissions and climate change to 2100 (IPCC, 2000). Table 16-1 summarizes these climate projections for the polar regions. In almost all cases, predicted climates are well beyond the range of variability of current climate. …
http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=599
——————-
…The chemical and physical properties of aerosols are needed to estimate and predict direct and indirect climate forcing….
…Modelled dust concentrations are systematically too high in the Southern Hemisphere, indicating that source strengths developed for the Sahara do not accurately predict dust uplift in other arid areas….
…For summertime tropopause conditions the range of model predictions is a factor of five for sulphate. The range of predicted concentrations is even larger for some of the other aerosol species. However, there are insufficient data to evaluate this aspect of the models….
Richard August 25, 2013 at 2:02 pm,
Call it what you like but the IPCC is filling a position equivalent to that of a marketing staff providing projections of business revenues to a CEO. Effectively, both are (more or less) linearly extrapolating perceived trends and hardly are forming a predictive model. You would think no one in their right mind would think of either is a prediction but too often people do conflate the two.
Even if the GCMs are truly predictive, the amount of future atmospheric CO2 concentration is an extrapolation without any real basis.
@Brian H: Another thing: A conditional prediction is perfectly falsifiable. If the conditions apply, but the future predicted for this case fails to happen, there you are. If I say “You will die in ten minutes if you jump off this wall”, you do so, and die only after an hour, then you have falsified my conditional prediction.
He’s entirely correct. If in 2005 I predicted the sun would go supernova in 2010, in 2011 the correct description for my prediction would be, “in 2005 he FAILED TO PREDICT the the sun would NOT go supernova.” Thus, the IPCC hasn’t made predictions of the truth. They’ve failed to predict a lot, but actually predict something, not so much.
DAV:
Your post at August 25, 2013 at 2:15 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399902
says to me
Say What!?
At August 25, 2013 at 1:45 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399874
you wrote
I said
THAT IS EXACTLY WHAT YOU SAID YOU CALL IT, TOO.
Furthermore, the “committed warming” is a specific theoretical prediction (n.b. NOT a model projection) of the IPCC.
The explanation for this is in IPCC AR4 (2007) Chapter 10.7 which can be read at
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-7.html
It says there
In other words, it was expected that global temperature would rise at an average rate of “0.2°C per decade” over the first two decades of this century with half of this rise being due to atmospheric GHG emissions which were already in the system.
This assertion of “committed warming” should have had large uncertainty because the Report was published in 2007 and there was then no indication of any global temperature rise over the previous 7 years. There has still not been any rise and we are now way past the half-way mark of the “first two decades of the 21st century”.
So, if this “committed warming” is to occur such as to provide a rise of 0.2°C per decade by 2020 then global temperature would need to rise over the next 7 years by about 0.4°C. And this assumes the “average” rise over the two decades is the difference between the temperatures at 2000 and 2020. If the average rise of each of the two decades is assumed to be the “average” (i.e. linear trend) over those two decades then global temperature now needs to rise before 2020 by more than it rose over the entire twentieth century. It only rose ~0.8°C over the entire twentieth century.
Simply, the “committed warming” has disappeared (perhaps it has eloped with Trenberth’s ‘missing heat’?).
This disappearance of the “committed warming” is – of itself – sufficient to falsify the AGW hypothesis as emulated by climate models. If we reach 2020 without any detection of the “committed warming” then it will be 100% certain that all projections of global warming are complete bunkum.
THE IPCC DOES MAKE PREDICTIONS.
Richard
Thomas Traill: You’ll see he defines conditional statements (“what if”) as distinct from predictions, and says all statements in the reports are conditional, e.g. based on certain possible emissions scenarios. I’m not sure this last strict assertion is true, but I don’t see that his credibility depends on it.
The emissions have exceeded the lower emissions scenarios, so the conditions for the conditional statements to be active are satisfied. So they are predictions now.
Thomas Traill says:
August 25, 2013 at 2:15 pm et al
Sounds like a barrister’s defence.
Don’t forget that no means no and yes means yes.
In this context predict means predict.
Remember the adage about the three great virtues, Faith Hope and Clarity.
And the greatest of these is Clarity.
Now you are playing games with “prediction” and “projection”.
The bottom line is that if whatever they said is almost correct it was a good “prediction”.
What Trenberth is doing is backing out of what they “predicted” because they are not anywhere near accurate. Just like a lawyer getting a guilty client off on a technicality.
Come on! “Might” versus “will” makes all the difference? Not in my book. I can predict it might rain and I can predict it will rain. I can project it might rain and I can project it will rain. Either set of sentences is an appropriate use of the word “predict” or “project” and are equivalent in meaning in this case. But that doesn’t make it good science just because it is a “might” happen scenario, no matter which word you use. So I don’t give a rat’s a## if one uses “predict” or “project”. If it is couched in terms of “might” you are engaged in bad science if the model you have developed can only give you a bunch of “mights”. Let’s call it for what it is. They ran their model a bunch of times and took the average. Based on a comparison to the observations, the results demonstrate the model should hit the editing room floor and in fact should have hit the floor several years ago. That the models keep running is testimony not to the “sciencificity” of the endeavor but to the power of money and the money of power.
I see quoted many uses of the word “prediction”, perhaps not always carefully distinguishing from projections. But no quotes where the IPCC actually says “We predict …”.
The distinction Trenberth is referring to is just common sense. Scientists can hope to say how the Earth will respond to human actions. But they can’t, as a matter of science, predict what those actions will be. So they calculate conditional responses based on suppositions of what we might choose to do. It’s our choice.
“””””””…….DAV says:
August 25, 2013 at 1:45 pm
There’s a big difference between the terms, Pamela.
An example of a projection: It’s cloudy so it might rain soon.
An example of a prediction: It will rain soon.
The latter can be verified while the first can’t be……..””””””
“Projection ” and “prediction” are two different words.
Any “model” of a physical system, when applied to actual input data to that system, WILL, within some error limits, PREDICT the actual observed output of the real system ; ALWAYS.
If the output of the “model” differs from that of the real system beyond some reasonable and consistent error bound; then by definition, it is NOT a model of the given system.
“””””””……An example of a prediction: It will rain soon.
The latter can be verified ……””””” Soon it rains…..Verification.
“”””””…….An example of a projection: It’s cloudy so it might rain soon.
………. the first can’t be (verified)……..”””””” Soon it rains……Verification OR
…..Soon it does NOT rain…….Verification .
Both statements are equally verifiable.
But the crux of the matter is, that any process or construction, that DOES NOT consistently PREDICT by emulation, the output of the actual system, is simply NOT a model of that system.
A projection is result of applying processes or constructions, that ARE NOT a model of the system.
One can weasel all one wants; but models PREDICT the consequences (within known error limits).
Does a ‘projection’ become a ‘failed prediction’ when the ‘what if’ is satisfied but diverges from future observations?
On another point this sounds like a ‘prediction’ to me even though the world ‘prediction’ is not used. I wonder whether Trenberth’s use of the words “future climate change is guaranteed” means global warming will pick up?
Trenberth has at least given us a guarantee of something.
Nick, you cannot write what you just did with a straight face. Can’t be done. It just makes you look as weasel-y. In the words of John Wayne, “I wouldn’t want to live on the difference”, between ‘predict’ and ‘project’.
So, …umm what is it when the weather service “predicts” a 50 % chance of rain next Thursday?
They often do use the word “prediction” even though qualified by some per centage of chance.
Must one wait ’til after the fact and it is then known that it DID or DID NOT rain to say it was a projection or a prediction?
But there is a quote which you might like. What’s your take on this, you may have missed it earlier. The IPCC said:
If you feel that the IPCC made a mistake then I would recommend you contact them immediately.
It’s amusing to watch Trenberth dance around the IPCC’s use of worthless projections in place of actual predictions, hoping to both promote catastrophism and avoid falsification at the same time. The only projections that have value in science are predictions.
“In fact there are no predictions by IPCC at all. And there never have been. The IPCC instead proffers “what if” projections of future climate that correspond to certain emissions scenarios.”
DAV says:
August 25, 2013 at 1:32 pm
“Technically, Kevin is correct. They are projections and not predictions.”
I can’t believe anyone is taken in by the illogic of this BS, even DAV, given the last clause that contains -“projections.. that correspond to certain emission scenarios”. What are these certain emission scenarios. They are that we will go on unabated with rising CO2, that we will make some effort to curb CO2 and that we quit emissions all together. Coupled with this is the certainty of the IPCC folks’ theory that increased CO2 means increased warming. And to compound it, when would anyone be justified in attaching certainty bands to projections? If the science is settled, then these are predictions no matter whatever else you may call them (IPCC properly refers to them as predictions). Why does Kevin T think it is a travesty because “we” can’t account for the lack of warming? Because the settled science says it should. The actual record of temperatures falls out the BOTTOM SIDE of the “stopping emissions scenario” while, indeed we have not curbed CO2 at all. KT is completely disingenous here. DAV, on the other hand is a social science semanticist. In science, words mean something and they are related to the theories that are being propounded and the expectations of developments arising from the theories. If Kevin didn’t know the difference between projection and prediction (and many in the CAGW camp don’t appear to) ignorance wouldn’t make it okay.
richardscourtney August 25, 2013 at 2:30 pm
If we reach 2020 without any detection of the “committed warming” then it will be 100% certain that all projections of global warming are complete bunkum.
Except that a projection is a statement effectively saying “this is where things are headed.” A projection is never wrong except perhaps when it is inappropriate or outright incorrect. Try to understand that the IPCC mission is merely writing reports and report writers rarely make predictions. It’s not in their task description.
There IS, though, a tacit prediction which has been falsified — namely, the temperature will rise as CO2 concentration increases. This hasn’t happened in the last 15+ years. Note that this is a climate science prediction and not one from the IPCC.
The alarmists make a mostly tacit prediction that curbing CO2 emissions by taxing fossil fuels to make them more expensive will affect (cool the) climate in a substantive way. This prediction is surprisingly unequivocal when made by eco/green activists, and displays an amazing level of scientific hubris.
I don’t see what the problem is.
The IPCC is in the business of making scary predictions.
No scary predictions, then no one would fund the IPCC; then a whole lot of parasitic pseudo-scientists would have to find a real job at a much lower remuneration.
Therefore, “I make scary predictions in order that I may prosper” is the mantra of those who write for the IPCC.
QED
Human nature, chaotic data and financial incentives.
Talk about a volatile mix.
Trenberth is an idiot. An if-then statement IS a prediction. I predict that if you try to cross the rotted footbridge then you will end up in the water. If the person tries (as co2 has continued to rise apace) the prediction will either be proved wrong or right.
DAV:
Having read your post addressed to me at August 25, 2013 at 3:10 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399934
I wonder if your name is Trenberth.
My post at August 25, 2013 at 2:30 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399910
(a) pointed out that the IPCC makes a prediction according to YOUR definition of a prediction
and
(b) pointed out (with reference to, quotation of, and link to) that the IPCC statement about “committed warming” is a theoretical prediction and NOT a model projection.
Hence, my post stated that THE IPCC DOES MAKE PREDICTIONS.
Your reply mentions my observation that the failed IPCC prediction falsifies the models which make projections and discusses the projections. Such a reply is disingenuous.
Your reply then makes the untrue assertion that
But that IS a prediction from the IPCC. This is explained in Chapter 9 Section 2 of the Working Group 1 (i.e. the ‘scientific’ working group) of the most recent IPCC Scientific Report (AR4) which can be read at
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-2-2.html
Richard
Has Travesty Trenberth ever got anything right ??
Seriously
THE IPCC DOES MAKE PREDICTIONS.
No. At best they are REPORTING predictions. The net result is a projection based on what they are reporting. They do at times give the impression that the work is their own. I’ll hand you that.
Thomas Traill says on August 25, 2013 @ur momisugly 1:49 pm: “he defines conditional statements (“what if”) as distinct from predictions, and says all statements in the reports are conditional, e.g. based on certain possible emissions scenarios . . .”
With a strong background in modeling, I am familiar with the analyst’s distinction between a prediction and a projection based on a scenario’s set of inputs. However, this situation is an example of why climate alarmists have such low credibility among high-information followers of the AGW debate. To claim that there are no predictions because they are discussing model projections is weaseling semantics beyond any sense of credibility. We can examine the values of the inputs of reality vs. the inputs of the scenarios, and the inputs of reality are consistent with the inputs of the scenarios — or higher — and the scenario output in lower than the reality, then the modeler — or the the model’s supporters — should have the integrity to admit that the model is not reliable.
Instead we have the climate activists claiming that they were not actually making predictions, so there is nothing to see here. No integrity and that removes any chance of credibility.