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….
Pamela Gray says:
August 25, 2013 at 6:46 pm
Whether or not it is a computer model or a thought model, the “projection” of that model into the future provides predictions at any given point along the projection.
===========
this is actually quite an important insight. it provides a means to turn past IPCC projections into predictions, to see how well they match reality, which is the basis of the scientific method.
there is no value in analyzing current projections, because nothing can be concluded either way. However, for past projections an analysis can be done:
A. for those past projections where the forcings match today’s observations, how well do the past projected (NOW PREDICTED) temperatures match today’s observations. If they don’t match, at least within the predicted bounds, then the model has been falsified.
B. for those past model projections where the forcings do not match today’s observations, nothing can be said either way. except perhaps that the model builders chose poorly in the scenarios they chose to model.
so, current model projections are without value, as are past projections where the projected scenario does not match reality. only those past projections whose inputs (forcings) match the current observations are of any scientific value from the point of view of validation.
Nick Stokes says: August 25, 2013 at 4:14 pm
IPCC projections are predictions subject to future changes
Gotta love it … is this some sore of ‘double speak’?
The IPCC make ‘projections’ based on projected future emission scenarios, and predicted (modelled) climate responses to that scenario, but when the emission scenario eventuates and the climate response does not, the failed climate prediction is somehow NOT a failed prediction?
one problem is that the Warmistas use words like…might and may…and then go on to assume that is is fact…journalists do this all the time…the general public is ill informed…and assumes it is fact.
ferd berple says: August 25, 2013 at 9:48 pm
Pamela Gray says:
August 25, 2013 at 6:46 pm
Whether or not it is a computer model or a thought model, the “projection” of that model into the future provides predictions at any given point along the projection.
===========
this is actually quite an important insight. it provides a means to turn past IPCC projections into predictions, to see how well they match reality, which is the basis of the scientific method.
there is no value in analyzing current projections, because nothing can be concluded either way. However, for past projections an analysis can be done:
A. for those past projections where the forcings match today’s observations, how well do the past projected (NOW PREDICTED) temperatures match today’s observations. If they don’t match, at least within the predicted bounds, then the model has been falsified.
B. for those past model projections where the forcings do not match today’s observations, nothing can be said either way. except perhaps that the model builders chose poorly in the scenarios they chose to model.
Well, Pamela is clearly wrong – model projections give you a calculated response to a supplied forcing. Change the forcing and you get a different answer. That is well understood. The forcing is the scenario.
But ferd’s A and B are right. The projection says, if the scenario happens, then this will happen, That is perfectly testable. We’re used to arguing about whether Hansen 1988 got it right, and which scenario applies. Of course, people disagree, but at least the facts are there to argue about.
And B is right. If the scenarios completely missed, there’s nothing can be said, and the projections were a waste of time. So they do try hard to get a good range. Of course, no scenario can be exactly right.
In re this “projection” whiplash: If Trenberth was a photographer, he would be Robert Maplethorpe.
Sorry Nick. I am right. The scenario is the input (IE set this dial to this number, put this fudge factor in, run it several times to cancel/reduce natural variation, and then use the average trace with error bands as the projection of the scenario). The projection is the entire output, not just the end of it. The prediction is every point along the projection and is compared to actual observations.
It’s done in rate of improvement calculations all the time. We take baseline data and say this about it. We add something to the educational curriculum (IE the scenario: more time, more repetition, additional time with supplemental curriculum, etc) and say that we want to see an accelerated learning rate and plot one (the projection). We then begin treatment and take observations to compare to our hoped for projected trend to see if our prediction at any point in time is right. If it is we continue with the treatment. If not we let the current treatment run a little longer. If the predictions still are not what we want to see, we change the treatment.
Pamela Gray says: August 25, 2013 at 11:18 pm
“Sorry Nick. I am right. The scenario is the input (IE set this dial to this number, put this fudge factor in, run it several times to cancel/reduce natural variation, and then use the average trace with error bands as the projection of the scenario). The projection is the entire output, not just the end of it. The prediction is every point along the projection and is compared to actual observations.”
Well, any computer provides an output that is a response to its input. But if you want to call it a prediction, the question is, what of? In this case, the IPCC says the input numbers are a scenario, and as ferd says, it is then a prediction of real climate subject to that scenario. If that scenario didn’t eventuate, there’s no point in comparing the results to observations. The stated condition didn’t apply.
Conversely, if the scenario did unfold, it’s a real prediction, and you can say whether it was right or wrong.
Ferd Berble says:
“great. if the science is settled, then what possible need is there for climate scientists? there is nothing left for them to discover. they should all be made redundant and engineers hired in their place to make things happen.
take the 100 billion dollars or so spent on climate science and redirect this to climate engineering. you want it hotter, we will make it hotter. you want it colder, we will make it colder. and for a lot less $$ than currently being quoted. and we will turn a profit at the same time, so that taxpayers and energy consumers aren’t stuck with the bill.”
Difficult to argue with that.
But then, the climate scientists could be wrong about CAGW – they obviously are – and that means they have sucked at the global financial teat for far too long and should now all be kicked out unceremoniously into the real world on their feather bottomed backsides.
Either way, it is difficult to argue climate scientists and their ‘research’ are anything other than a huge waste of financial resources, which could be much better spent elsewhere.
What scares me about the upcoming AR5 is that governments have to approve the final conclusions of this document before it can be published. So no matter how good or bad this document is, the press/media will be reporting on the whims of a bunch of greenie bureaucrats with a remit to produce excuses for new energy taxes.
DAV:
At August 25, 2013 at 3:41 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399950
You refute my explanation that
By saying
NO! The IPCC reports what it has endorsed and adopted.
When the IPCC adopts a prediction and then reports the prediction then the IPCC is making the prediction.
Similarly, I am making a prediction if I run into town shouting “The world will end tomorrow. I know because Mystic Meg told me.”
Richard
Irrespective of whether they are called projections or predictions, both are falsifiable entities and both have failed the test. So the whole issue boils down to semantics.
Nick Stokes:
At August 25, 2013 at 4:45 pm
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1399987
you say
It would help if you read the thread before writing such stuff.
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
I quoted IPCC AR4 (2007) Chapter 10.7 which can be read at
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch10s10-7.html
That quotation says
Nick, do you understand the difference between “implying” and “would be expected”?
They are making a clear and unequivocal prediction based on a stated present situation (i.e. the current energy imbalance of the Earth) when they say
And they are explaining what their prediction would be if something additional occurred when they add
Note the word “expected”. They are discussing what they expect and – as such – they are saying what they think will happen.
To avert your predictable response, I quote the Oxford English Dictionary
verb
[with object]
regard (something) as likely to happen:
we expect the best [with object and infinitive]:he expects the stock market to sink further
[with clause]
we expect that farmers will harvest 63 million acres of hay
Richard
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.
______________________________________________________________
But predictions contain uncertainty so your example doesn’t quite work either.
“It will rain soon” is a prediction that may not eventuate given the uncertainty in your prediction.
Lets face it there’s bugger-all difference its just BS sematics.
richardscourtney says: August 26, 2013 at 1:34 am
“Nick, do you understand the difference between “implying” and “would be expected”?”
You haven’t quoted the whole para. It starts:
“The multi-model average warming for all radiative forcing agents held constant at year 2000 (reported earlier for several of the models by Meehl et al., 2005c), is about 0.6°C for the period 2090 to 2099 relative to the 1980 to 1999 reference period”
and they go on to discuss, as you say, the “committed warming trend” (same condition). This is a scenario projection, in this case of GHG’s held constant (basically Hansen’s original scenario C). It’s in no sense a prediction, because no-one expects that to happen. They are just base numbers.
And they go on to say
“About twice as much warming (0.2°C per decade) would be expected if emissions are within the range of the SRES scenarios”
again a scenario projection – note the “if”.
Go to the IPCC homepage and type “predictions” into their search engine. One interesting link is to the Policymakers Summary http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_spm.pdf which shows in their table of contents a section on “How much confidence do we have in our predictions? xxvii”. That section wiggles around with all the uncertainties involved but states “For this reason, climate change is likely to be greater than the estimates we have given”. In other words “It’s going to get bad, we’re just not sure how bad”
Nick Stokes:
re your silly post at August 26, 2013 at 3:10 am which evades the point made in my post at August 26, 2013 at 1:34 am
http://wattsupwiththat.com/2013/08/25/trenberths-ipcc-claim-of-no-predictions-by-ipcc-at-all-refuted-by-ipccs-own-words/#comment-1400177
I made the full quotation in my original post which I was explaining and I linked to that post from the explanation you have avoided.
If you had an argument then you would have presented it. Pretending I did other than I did as evasion of the issue demonstrates that YOU know you have no argument.
Richard
richardscourtney says: August 26, 2013 at 3:46 am
“If you had an argument then you would have presented it”
The argument is perfectly clear. Every quote you have given from the IPCC in that post is conditional on future emissions – exactly the kind of projection that Trenberth said they make. You have nothing.
Nick both you and the IPCC are full of recycled hay, they used the words predict and project interchangeably because they knew that the people that these reports were aimed at would not know the difference between them. That is the whole point, by using the words like they have they are guilty of obfuscation and they know it and so should you, if you don’t then you need to stop and take a step back and let some fresh air into your system.
Thomas Traill says:
August 25, 2013 at 1:58 pm
@Graphicconception and David, UK: How are you supposed to predict if it will rain in three months if you don’t know what the humidity will be. It is perfectly sound that the IPCC uses projections, because it doesn’t know what the emissions will be. Anything else would be too simple. And to answer your rhetorical question: If, as a young man/woman you you are told that you will probably produce children if you have regular, unprotected intercourse, that is a very useful conditional statement. I am mystified how you can generalise them as being pointless.
You misunderstood, or maybe I was unclear. I meant to say that projections that are not predicted to happen are useless. Remember, Trenberth’s (untruthful) point was that the IPCC does not make, and has not made, any predictions. Lots of projections, but no predictions. This is not true, and would be silly if it were.
If a man and woman have regular, unprotected intercourse, it is a reasonable prediction that they will produce offspring sooner or later. You could lay reasonable odds on it. And you could also then make projections about, say, how long they will take to conceive, based on frequency of intercourse, quality of sperm, genetic compatibility, and other factors. These projections are useful precisely because they are based on a reasonable prediction (that conception will happen).
One could also make projections for the scenario that if an alien were to come down and have intercourse with a female, what the various possible outcomes may be. She could give birth to a human-alien hybrid. The pregnancy could fail due to lack of genetic compatibility. Or… well, who cares. An alien impregnating a human ain’t predicted to happen, so is a completely pointless exercise.
The IPCC of course DOES make predictions, which is why, at least in its own eyes and many others, it is able to claim that its projections are useful, as opposed to pointless.
Still mystified?
Nick Stokes says:
August 25, 2013 at 6:43 pm
Theo Goodwin says: August 25, 2013 at 6:00 pm
“If you believe that a scenario generated by a computer model is about the future then I challenge you to show me the logical connection between that scenario and the future. What is that connection?”
“Scenarios are not generated by computer models. Scientists are not expert at predicting future human decisions, so they invite discussion ( see the SRES process) and make projections based on a range of scenarios. The idea is that if you want to know what will happen, look at the scenario range and find the one that you find most likely. The AR4 says, in its glossary:”
So they arbitrarily attach their own estimate of likelihood. No such estimate can be inferred from the scenario itself.
“For someone to present himself as a scientist and then, as a scientist, to offer a forecast is nothing less than cheating. Scientists do not forecast. A forecast is a WAG. Scientists predict or not. “
“So what do all the Met offices do?”
They do WAGs as all weather people have always done. Their record of success is so poor that they now deny that they do forecasts beyond what the TV people do.
“But of course scientists makes predictions subject to scenario. Newton says that if you apply a force to an object, you’ll get an acceleration proportional to the force. He doesn’t predict that you’ll actually do it – that’s the scenario.”
Newton uses his laws which are stated as universal generalizations and are used in genuine inferences to the phenomenon to be explained. There is a logical connection. You do not have a clue what I am saying. Read Hempel’s “Aspects of Scientific Explanation” or Scheffler’s “Anatomy of Inquiry.”
Jimbo says:
August 25, 2013 at 5:09 pm
“Do you agree that the IPCC has in the past made a prediction? The IPCC says so as I have pointed out repeatedly.”
Yes, I agree. They present themselves as summarizing the world’s best science and, therefore, present themselves as making predictions. When challenged, they deny that they make predictions. In sum, they cheat.
Nick Stokes says:
August 26, 2013 at 4:14 am
richardscourtney says: August 26, 2013 at 3:46 am
“If you had an argument then you would have presented it”
“The argument is perfectly clear. Every quote you have given from the IPCC in that post is conditional on future emissions – exactly the kind of projection that Trenberth said they make. You have nothing.”
Nick, Nick, Nick. The only thing there is reasonable certainty about IS the emissions of CO2 into the future. When you say lets look at three scenarios -rapid curtailment of emissions from now on, reduced rate of emissions from now on, or business as usual. There is only one reasonable scenario here and it is between a somewhat reduced rate and the business as usual scenario. Shall I predict that for you? Do you disagree with this? Now even if you believe that this is not correct, that tomorrow it is likely we will stop emitting, your “science” has a prediction conditional on the scenario. Are you saying that they make the projection because there is little confidence that, given one or each of the scenarios, we have no idea what the temperature will do, or are we saying, since we don’t know what CO2 scenario is in the offing, we don’t know what prediction is appropriate. So far, what we have is a recent temperature record that falls below a scenario of rapid curtailment of CO2 emissions. Really, the theory as you know it has been grandly falsified. This great disappointment has led to the semantic nonsense that these were only projections and is an attempt to misdirect away from the miserable predictions. The UK Met Office convened a meeting of friends to explore the reasons for UK’s DISAPPOINTING WEATHER! Not its completely upside down predictions for UK weather. UK’s weather is lousy and disappointing as usual.
I agree with Pamela. There is no use trying to convince Nick S.
He is immune to logic.
Give him a sandwich board and send him out on the street.
http://www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_spm.pdf
Page 5 of the above PDF, for Nick and everyone else to see:
“Based on current model results, we predict:
• under the IPCC Business-as-Usual (Scenario A)
emissions of greenhouse gases, a rate of increase of
global mean temperature during the next century of
about 0 3°C per decade (with an uncertainty range of
0 2°C to 0 5°C per decade), this is greater than that
seen over the past 10,000 years This will result in a
likely increase in global mean temperature of about
1°C above the present value by 2025 and VC before
the end of the next century […] ”
There are multiple other instances of the word throughout the document, including the phrase “our predictions” found earlier by another contributor here.
So, Nick, that’s the answer to your challenge to find the statement “We predict” in an IPCC document – and it’s in the most obvious of places, namely in the “Executive Summary” in the Policymakers’ Summary. If “predicting” something weren’t the main business of the IPCC, why would they put the term in such a prominent place, where it’s sure to be read even (and especially) by those with only very cursory knowledge of the subject and the organization? QED.
Rather than arguing with these guys we should highlight their arguments. I can see the headline now .
Headline: IPCC claims it has NEVER predicted the Earth would warm
Subtitle: Travesty Trenberth states “There are no predictions by IPCC at all. There never has been.”
The fact that Trenberth and the IPCC are both playing a semantics game is absolute proof that Trenberth is not practicing science and the IPCC is not reporting the science. It’s called politics. Why should we believe anything either of them say?