We have been expecting too much from the IPCC about its confidence level increase: the explanation may actually be simple… and surprising.
Guest essay by Stephane Rogeau
Image: From IPCC FAQs
Many people are wondering what actually made the IPCC raise its confidence level about the fact “human influence has been the dominant cause of the observed warming since the mid-20th century” from 90% to 95%, since its last report in 2007.
Most of the time, it is argued that there has been no warming since 2007 whatsoever, which makes the increase of confidence level in the IPCC’s statement very dubious. But it may be the other way around: because there has been no warming, the IPCC raised its confidence level! And it actually makes sense… at least inside the thought paradigm of the UN organization.
The reason may actually be simple, for one reason: the theoretical warming due to anthropogenic CO2 is, for the IPCC, a given.
It is what makes the climate models “work” (i.e. match more or less historical records). It is actually the basis of the IPCC’s line of reasoning: we cannot find any other way to match our models with the data than by entering feedback assumptions that give climate sensitivity to CO2 the value x… therefore its value has to be around x.
Based on this given assumption that cannot be disproved by facts anymore, and knowing the quantity of CO2 released by human activity, one can easily calculate the theoretical human-induced contribution to global warming since 1951 (let’s call it HIC). Discrepancy with observed global warming (OGW) is, of course, due to natural variability. Therefore, the proportion of human influence in observed warming between 1951 and year “n” is simply p(n) = HIC(n) / OGW(n). If, in year n, the theoretical human-induced contribution since 1951 is for example 0.4°C, and the observed global warming is 0.5°C, then the calculated proportion of human influence is 80%.
Obviously, as we release more and more CO2 into the atmosphere, the human-induced contribution is an increasing function of time: HIC(2012) >HIC(2007). On the other hand, the so-called “hiatus” means OGW(2012) = OGW(2007), as no warming has been observed since 2007. Then it’s just basic arithmetic: p(2012)>p(2007).
Long story short: the proportion of human influence in observed global warming has increased since the last IPCC report because temperatures have leveled off. Translated in terms of confidence level: if the IPCC was 90% certain that human activity was responsible for more than half of the observed warming in 2007, it is not surprising that the confidence level for this same proportion has now risen to 95%.
To conclude: the less warming, the more confident the IPCC about its claims to policy-makers.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
There is no human signal in the CO2 data.
There is no human signal in the temperature data.
There is no empirical evidence for the so called “GHG”.
Jim Rose says:
November 21, 2013 at 6:31 am
I would like to know effectively how many pieces of information need to be established from hind casting
===============
There was a posting a while back (Willis?) that showed that various models made very different assumptions about aerosols, but delivered near identical results. This is because the model builders either consciously or unconsciously select the other parameters to match their expectations.
For example, say you built a model and it showed -5C cooling over the next century. Most model builders would immediately think the model was wrong and reject it – they would adjust the parameters. But what if the model is actually giving you a correct prediction? Similarly, what if the model showed 20C warming over the next century, Most model builders would think this wrong and reject it as well. But what if it was actually correct?
So, what we see from these extreme examples is that the model builders are allowing their expectations to predetermine the results. Too much warming or too much cooling, as determined by their own beliefs about the future are being used to select the parameters. As such, what the models are showing is not the future, but rather what the model builders believe the future will look like.
Formally, what the models are trying to do is solve for a system of multi-variant non-linear equations. This would allow them to hindcast the data and solve for the correct parameters. However, the reality is that such a solution is beyond the capabilities of modern mathematics, because of the sensitivity of non-linear systems.
The sensitivity of on-linear systems is such that many combinations of parameters will provide the same solution within the error bounds, and there is no way to determine which solution is correct.
for example, you might find that
a=0.993393, b=3.5533222
a=1.343432, b=2.3234422
a=2.345345, b=2.6767867
both provide the exact same solution +-.001 error, so which solution is correct? There is no way to tell.
It would be interesting to survey/quantify the original “warmists” who posted here years ago and now are changing their minds (or already are committed skeptics/deniers).
Hey, that is a nice pictograph……..of greed.
@Flydlbee said: “Following this technique, if the climate cools, the confidence level will go over 100%”
Let’s not mix confidence level with proportion of human-induced contribution. With this IPCC logic, if the climate cools:
– the proportion of human-induced contribution may exceed 100% (actually, it is almost the case, according to the IPCC, as they wrote that “the best estimate of the human-induced contribution to warming is similar to the observed warming over this period”)
– the confidence level about the fact the proportion of human-induced warming is more than half of observed warming will approach or reach 100% (but will of course not exceed it).
Sorry Stephane but I must take issue with the wording your have on your time line:
” the IPCC was 90% certain that human activity was responsible for more than half of the observed warming in 2007, it is not surprising that the confidence level for this same proportion has now risen to 95%.”
In 2007 that is not what they said (please see the original quote if you can). They said they were 90% certain that human activity was responsible for ‘most’ of the observed recent warming.
In 2013 they reduced the proportion from ‘most’ to ‘more than half’. They are more certain but only about a smaller fraction of it. They did not say their increase in confidence was for the same ‘most’ fraction. This subtle difference was pointed out to me by one of the AR5 expert reviewers.
In another thread we are talking about prestidigitation. This is another example. They are emphasizing the increase in confidence level (the Red Scarf), but quickly and quietly changing the thing in which they have so much confidence. I am 95% confident they think we will not notice the swaperoo.
imagine two lines intersecting at right angles. It is easy to find the intersection rather precisely, even allowing for some error in the lines. Now imagine the lines are nearly parallel. Even a small error will through the point of intersection way out. As such, near parallel lines are poorly behaved when it comes to solving for intersections. Similar problems occur with systems of with non-linear equations such as climate models are trying to solve. Very small errors in the data lead to large errors in the results, due to the difficulties in solving poorly behaved problems.
Confidence Game. Also, confidence trick; con game.
def. – A swindle in which the victim is defrauded after his or her trust has been won.
The swindle continues….. with higher confidence.
Science par excellence at work.
But what the “more than half” with the 95% confidence actually means? The GISTEMPS >0.3C or the HADCRUT4 >0.23C (they actually differ 23%) or the HADSST3 >0.15C (which actually differs 34% from the HADCRUT4 and 50% from the GISTEMP)
Now, I’m lost, when trying to get back to the 95% confidence with 97% consensus my probability calculation apparatus just crashed and doesn’t seem wanting to reboot anymore likely overwhelmed by the weight of the truths.
So if it actually cools in the future but the confidence in the human contribution is rised over the 100%, wouldn’t it paradoxicly mean the contribution is having negative cooling effect just to confirm the Lenin’s negation of negation thesis and show the leftist hyppeies are right anyway after all, while the rightist fascist deniers are left emptyhanded again in their SUVs and small jets?
@Crispin in Waterloo but really in Ulaanbaatar:
If this was true, I guess we could call it a nasty way to confuse policy-makers, and it would be a shame for the IPCC, as they are supposed to speak clearly to non-specialists.
If I look at the image at the beginning of the article, what is written does not reflect what the expert you are talking about is saying.
If there is one event that is capable of stopping the AGW nonsense real quick, it’s this:
http://rt.com/news/climate-change-walkout-warsaw-050/
My bets are that within coming weeks many Pro western AGW government spokespersons will be starting to quote “the Pause” and maybe “It ain’t all that bad after all”. Who knows by some miracle they may even start quoting WUWT, CA, Roy Spencer PhD, Dyson Freeman ect?
It boils down to money #### the science! LOL
It’s called the Little Red Choo Choo effect and concerns the acquisition of super tanker quantities of money and power and control and authority and grandeur and legacy and… Oh, did I say money? Anyway, it’s the belief by the UN that it can acquire these things through the AGW scare and its naughty child, the IPCC, if only it thinks it can. And, with each day, it thinks it can a little bit more. And if it only thinks it can more today than it thought it could yesterday it may find that it’s getting closer to having thought it could enough to where if it thinks it can tomorrow and then thinks it can more on the day after tomorrow it may have thought it could enough to finally get near the crest of that hill of peasant resistance so that with a little bit more of thinking it can it may have thought it can (this is really getting hard) enough to get over the hill if only it thinks it can.
Now, if one converts, “I think I can,” to percentage points agreement you have the same thing. This is also related to the Alice in Wonderland effect, the Humpty Dumpty effect, the reverse Robin Hood effect, and Larry Flynt.
Looks like the ipcc confidence men (and women) are filled to the eyeballs with “confidence”. Or something else.
well you should focus on the form…
in real science they would give maximum natural variability with errors bars
warming with errors bars…
and then it would be up to you to think is is very likely or not…
this way they can t be wrong.but unlucky…
well if i tell you tomorrow it will rain from 0 to 10 mm i can be wrong
if i tell you tomorrow the probabilty that it rains more than 5 mm is 95% and it actually rain 4 …i am not wrong but unlucky…
It is not science it is expertise…
@Stephane
>If this was true, I guess we could call it a nasty way to confuse policy-makers, and it would be a shame for the IPCC, as they are supposed to speak clearly to non-specialists.
This was discussed in a thread about two months ago and someone looked up and cited the actual wording. At the time, the press were reporting that AR5 was saying that the 95% confidence was in the AR4 2007 wording. The clip you have above has them saying AR4’s 90% confidence is in the AR5 wording – the opposite case and clearly impossible without time travel.
The texts are different. Simple as that. There is clearly a plan to deceive. The MSM lapped up both of course – after all what would a wordsmith know about verbal weaseling and misdirection?
A good point of confidence: belief in smarts and belief in model will be unchanged with time as along as you allow a variable such as “nature” to have an unknown impact at any given time. Observation then “proves”, really, not your smarts or model, but quantifies the natural portion. If today the temperatures are holding steady, but smarts and model say they should be going up, then observation proves there is a natural cooling force equal to your models warming forces.
The genie in this IPCC narrative is the unstated natural variable. When it is warming – 1975 to 2001 – they can say that the natural warming MAY be zero or even slightly negative ((which is what their models assume). All temperatures that rise represent the effect of CO2. After 2001, due to aerosols or aerosol-induced clouds, the natural cooling PROBABLY is greater than before, so temperatures that don’t rise represent the negative forces equal the positive forces.
It is a brilliant set-up. It is just like stockbrokers and the market: when they make you money, it is because they are brilliant, farsighted and your money has been invested wisely. When they lose your money, the market went south due to unknown political or hidden economic parameters (nature), however the FUNDAMENTAL forces of market growth still exist (the US is strong and resilient, and China and India are industrializing), so you should give the ‘broker your money because the future will be very, very profitable.
Military historians would probably recognize this also. The victories are due to planning and brilliance, the loses due to hidden, uncontrollable forces (like Russian weather). Never is the planning and brilliance in question.
This view does not bode well for mankind. Forever stepping on our own bootlaces and blaming the irregularity of the ground for our pratfalls.
From the graphic, by 1995 they had only stepped in it. By 2013 they are almost completely full of it.
Oh Look! A lovely graphic depicting the level of Radiative Kool-Aid in the average climate alarmist, over time. Very nice, thank you UNEPt.
I don’t believe people are using the correct definition of confidence in this discussion. It’s not that they are believing they’re confident, the science is now more to be held in confidence. Meaning they are now 95% sure they will hold the science that applies in much stricter confidence. They will be much more secret now than in the past.
And kindly note, since 2001, only gases emitted by Humans, in a UN certified greenhouse, need apply.
How much warming could a warmer warm if a warmer could warm worlds?
I find the the most ludicrous aspect to be the growth in claims of “we are already seeing changes to….” . ………everything? everywhere?
The heap of imagined and always terribly worrisome changes attributed to the observed minuscule temperature change has been a lesson in mass delirium unequaled in human history.
There are literally millions of people having hallucinations triggered by a steady flow of higher authority misinformation and a cause too inflated to fail.
This far reaching parasite of confusion spreads like a mental pandemic infecting more at a pace
truth cannot reverse.
Those IPCC silhouettes above might as well have hockey masks on.
And with so most of academia and the media making the AGW boogeyman look so real we’re in for many sequels for years to come.
Let us model very simply the probability of the behaviour of the average temperature of the climate system over a 15 year period as follows:
Temp AGW NGW
Increase 40% 25%
Pause 40% 50%
Decrease 20% 25%
The numbers in the left hand column (AGW) indicate the probability of the climatic temperature increasing, pausing or decreasing over the period if anthropogenic global warming were occurring. The numbers on the right indicate the same probabilities if recent warming were a random natural event (NGW). As you can see, the probabilities are skewed towards warming in the AGW scenario, and since in none of the climate models was there the suggestion that the climate would pause, we have conservatively assumed a slightly lower probability of a pause.
In the NGW scenario we have no reason to believe temperature would go up or down, and our best guess is that it will remain broadly stable.
We also set out current belief that the AGW scenario is the correct one at 90%, and thus in NGW it is 10%.
Now we bring in the good Reverend Bayes’ theorem. This updates our belief based on the fact that a pause in fact occurred during the 15 year period.
Probability
P (Pause │ AGW) 40%
P (AGW) 90%
P (Pause │ AGW) x P (AGW) 36%
P (Pause │ NGW) 50%
P (NGW) 10%
P (Pause │ NGW) x P (NGW) 5%
P (AGW │ Pause) = P (Pause │ AGW) x P (AGW) / [P (Pause │ AGW) x P (AGW) + P (Pause │ NGW) x P (NGW)] 88%
So under the conditions defined, our belief that AGW is the true scenario has decreased by 2% given that a pause occurred!
If you play around with these numbers on a spreadsheet so that the probability of a pause in the AGW scenario was only 30%, then the decrease in our belief is 6%.
I therefore pose to you the question of how an event that is less likely under an AGW scenario than an NGW scenario, and then in fact occurs, can increase our confidence in the AGW scenario by 5%.
Tim: “If you play around with these numbers on a spreadsheet so that the probability of a pause in the AGW scenario was only 30%, then the decrease in our belief is 6%.”
Not that I don’t understand your point. But it’s worth noting that experimental results are not contingent on belief.
How IPCC claims can be at the same time consistent and absurd.
Simply put no AGW no IPCC , they are parasitic organisation whose very existence depends on its ability to feed of ‘the cause’
They really had no choice but to be ‘more certain’ , they cannot ever be less certain or their ‘dead meat’
That is actual normal practice for UN bodies , so to be fair to them although the scale if far bigger , the actual approach is standard.
I believe the mann bar charts refelect the situation accurately. The only problem I see is that they were done in blue. A more accurate color would have been brown.