Bishop Hill Conveying truth 3
Jan 17, 2012 Climate: MetOffice Climate: Surface With nothing of any great import on the newswires today, I'm going to return to the subject of the Met Office's 2010 briefing to central government. The next statement I want address is this one:
Over the last 100 years the Earth has warmed by about 0.75 degrees Celsius and that warming is accelerating.
This is supported by a figure (click for full size):
;)
The original caption reads:
Past, current and future changes in northern hemisphere temperatures relative to 2000.
I think the first part of the statement is supportable (although perhaps with caveats), but is there any evidence to support the second part? Surely the words above grossly misrepresent the temperature history of the last half century? Surely the graph lends no support to the statement made at all? I don't think my saying so is even controversial - some readers may have seen James Annan's recent observation that 'there is little sign of the acceleration in warming that most models had predicted'.
We've all let off steam about the quality of this briefing on the earlier threads, so I'd be grateful if readers could refrain here, and stick to considering how recent temperature history should be described?
Reader Comments (76)
Jeremy Harvey
The bit about the error on the mean being lower that the error on an individual measurement was not an aside.
Not in my statistics book. I do not care for Bayesian statistics or its wishful thinking. You can not measure one inch with an unmarked piece of wood that is "sorta a foot long" no matter how many times you try it.
And once again I point to the fact that there are countless thermometers involved, all of which have unknown accuracies. And that is just the instrument issues. The procedural issues are far sloppier.
cosmic
You clearly understand the difference between "doing the math" of taking an average of a set of numbers and what that average means. You are right that the confidence limits are what matter. Your examples are quite right. You really want to have 10 times the precision of the measurement taken. That is, I would have some trust in the board being nearly 1 foot long if measured by an one inch ruler than measuring a one inch long board with one marked only in feet.
mydogsgotnonose Jan 17, 2012 at 1:42 PM
My understanding is that Prevost's principle of thermal equilibrium is that a set of bodies exchanging radiation adjust their temperatures so that, when they eventually reach thermal equilibrium, the power being radiated from body i to body j equals the power radiated from body j to body i.
Is this the same as 'Prevost Exchange energy' that you mention in your comments from time to time?
Martin A
Stephen Richards Jan 17, 2012 at 9:47 PM
What and disregard the Bish's injunction?
No fear!
Jan 17, 2012 at 3:15 PM | Don Pablo de la Sierra
"Next we look at the procedural inaccuracies. At what time of day and year were the measurements made? At what altitude, weather conditions and locations relative to heat sources such as cities, industrial plants, etc.None of this is controlled at all and we are told that they can somehow do this accurately?Yes, your brother is being kind. The 0.75°C claim is far more than laughable -- it is an outright deception."
Yep, give a Warmist any two temperature readings and they are perfectly comparable. Not one of these statistical geniuses can define his "event space" for temperature readings. I doubt that one of them even knows what the phrase means.
Jan 17, 2012 at 3:15 PM | Don Pablo de la Sierra
@cosmic and @don... see Fred Dibnah isn't such a fool. Thanks. Using common sense? Anti-science deniers the both of you.
Thanks to BH and to Green Sands for highlighting the two graphs.
As a UK taxpayer, I am disgusted with the Met Office who it seems are overtly misleading UK policy makers with the above graph and assertion that the rate of warming is accelerating, when the relevant graph on their own website clearly shows that temperatures have actually stabilised in recent years and even suggests that they are now in decline.
This mendacious propaganda for the WWF/Greenpeace/Hockeystick team cause has to stop if the Met Office wishes to regain any credibility.
My guess is that the "accelerating" statement that BH highlights probably arose from this figure from IPCC AR4 published in 2007, with linear fits to the global mean temperature data over different time periods, pointing out that the linear trend for the 25 years from 1981-2005 was steeper than that over longer periods.
Clearly the AR4 figure is now out of date.
The same false claim is made on the Met Office web site.
Later in the same page is another
I have emailed Richard to ask if he can get these changed.liefalse statement:Richard
The statement must have been out of date in 2010 too.
Richard, thank you for linking to that graph, one of the most blatant attempts by the IPCC to deceive readers as discussed here.
Dr Betts --
Although it's not the topic of this post, would you care to comment on the depiction in the cited figure of the "envelope of IPCC paleo records"? I found this to be misleading, see my comment on 17 Jan 1:42 PM.
Richard Betts:
If the Met Office statement was referring to that figure, why did it not say so? Can you not find out for us what data the statement was using?
I note that the acceleration was even greater in the period 1910 to 1940. It's a good job the Met Office wasn't in full alarmist mode back in 1940 or we'd have lost the war.
Martin A: the definitive experiment was done recently in Holland. The investigator climbed up a radio mast at night and measured Up-Down energy as a function of height up to 800 feet. Above ~100 feet, the signal had fallen exponentially to zero, proof of the Beer-Lambert Law for the IR emitted from the Earth's higher temperature surface.
The Oxymoronic Climate Scientist thinks that the Down signal ['DLR'] is evidence of an energy source and this heats up the Earth's surface a bit so that atmospheric temperature in the absorption zone rises iteratively by positive feedback dependent on GHG concentration, assumed to be a variable because the warmer air will hold more H2O.
In reality the DLR can do no thermodynamic work because it is exactly offset by part of the S-B total emitted energy from the Earth's surface. This is why the climate models predict 3-5 times real warming [if assumed mainly from extra CO2 and associated rise in H2O] and the modellers invoke twice real cloud optical depth and imaginarily high net AIE to offset it to the present zero level, no Null Hypothesis.
This is an affront to science because the OCS claims it is justified by peer review implicitly within the OCS sub-discipline when in ALL other disciplines, such a claim would be rejected because the majority peer review process has rejected incorrect scientific thought. Thus OCS is a scientific parasite which must be killed off before it consumes the whole body, the apparent aim of those who are funding this Lysenkoism..and the new 'back radiation' Phlogiston!
@Don Pablo
"Not in my statistics book. I do not care for Bayesian statistics or its wishful thinking..." There was nothing Bayesian in what Jeremy said: "The bit about the error on the mean being lower that the error on an individual measurement was not an aside." The error of the mean is 1/sqrt(N) times the error (standard deviation) of the population, N being the size of the sample. So your measuerments will spread widely around the correct value, but the mean of the measurments will be closer by the factor just given. I think this must assume that there is no systematic bias in the measurments which is where all the stuff about UHI came from that so exercised Anthony Watts. Myself I don't see what alternative there is to the 0.75 figure, it's the best we can do.
Richard Betts` link to the IPCC graph (@ jan18 2012 at 9.21am) is a reminder that these records are corrupted by the many land temperature station changes that were implemented c1990. These changes removed temperature stations at higher altitudes, removed several thousand stations with little direct overlap between those used before and after the change, focussed more on near sea level stations and, on average, marked a location shift away from the poles towards the equator. The implications of these changes were, as far as I am aware, dodged by the Muir Russell and Oxburgh enquiries (although invited to do so) and have been ignored ever since.
Thanks Peter. Indeed, nothing Bayesian. I did caveat my first comment on this point (yesterady at 3:42 pm) saying that if the pattern - in space and time - of measurement errors would need to be rather unusual to make the trend impossible to determine. I also readily acknowledge that an increasing UHI effect can perhaps account for some of the 0.75.
"You can not measure one inch with an unmarked piece of wood that is "sorta a foot long" no matter how many times you try it."
No, but if its length increases you can measure the increase.
As peter2108 has pointed out the accuracy of the increases is related to the number of inaccurate measurments taken.
But why the big debate about 0.75 DegC? I thought this was accepted as being about the rate of warming since the LIA?
It's the 'rate of increase' bit that's bollocks.
@ peter2108,
It may be the best we can do, but it's misleading to state the figure without reference to the uncertainty. The inherent uncertainty is increased by changes in station numbers and siting, including the UHI which also puts in an upward bias.
It invites assumptions, such as the figure being arrived at with instruments accurate to +/- 0.1C.
Nial,
The guesswork projections are another obvious load of bollocks.
Bearing in mind this was presented in 2010, it seems as if by 2000 they had an attractive narrative to present, and they found it convenient not to update it.
peter2108
Bayesian statistics is based on the philosophic position that you can repeatedly improve the confidence of the determination by trying it again and again, without actually improving the PRECISION of your measurements. It is a point of view many subscribe to. I do not.
You clearly know the MATHEMATICS of statistics from at least the formula level. As I noted to cosmic
cosmic clearly states that again in his recent post again. I suggest you stop thinking about the mathematics of statistics and start thinking about the meaning of statistics.
Given that a weather thermometer has to measure the range of -50C to +80C you are saying that you can determine something to the 0.75 /(130) or .577% level over a 100 year period. BOLLOCKS!
You can not accurately measure a bit of wood one inch long with another marked only in feet. You can approximate it, but not to the .577% accuracy. Why are you claiming that you can do the same with temperatures over 100 years?
@Don Pablo
One thing I have come to believe after many hours viewing climate blogs is that discussions that avoid mathematics and equations are non-terminating, indecisive, and eventually bad tempered. The great philosopher Thomas Hobbes wrote "For who is so stupid, as both to mistake in Geometry, and also to persist in it, when another detects his error to him?" and it does seem that there is a hope of settling an argument when it is supported by equations (not a guarantee of course - there are none of those. Hobbes himself engaged in a long argument with an Oxford mathematician over Hobbes' defective proof that the circle coud be squared). That's why I will decline your invitation to leave the mathematics of statistics and consider it's meaning. I'll try and to do both, though it is far from easy.
peter2108
if you stand back and consider the concept of a global temperature, what does it mean? Instantaneous measurement of every point on the surface of the planet? How many such points do you need to measure?
What we have is a bunch of proxies for that.
In the UK, temperature varies by about 30C in the course of a year. In places like Siberia or Nebraska, the range is more like 50 or 60 C. In the UK, the daily range varies from about 5C in the Winter to about 15C in Summer. The global proxies use an average temperature - sometimes just a crude mid-range measure. Things such as UHI can show up as an increase in Tmin and a reduction in Tmax, which might therefore be undetectable in Tavg.
Given the extent of this normal variation, how can we reliably detect a systematic change of about 2C over the course of a century. Would anyone even notice it?
I think the point is that we are looking at a piece of sales literature for a somewhat controversial product and prepared for a specific audience of loyal buyers.
There's no point getting too worked up about, and then sidetracked by, the technicalities.
If you say 'warming is accelerating', doesn't that mean the third derivative is positive?
Shouldn't it just be the temperature is accelerating?
Am I the only one who thinks that the graph is showing the year 2000 was 0.5°C cooler than the year 2000?
Once again, cosmic you have hit the nail squarely on the head.
I leave peter2108 with the following.
You go to the doctor, who diagnosis you with a serious, indeed fatal disease. However, the good news is he has the correct medicine to keep you alive. All he needs is to inject you with 1.5 cc of it, but he must be careful for too little will not cure you and too much will kill you. But all he has is a 50 cc syringe. So he takes it out and eyeballs the syringe as he draws out the drug, careful estimating where 1.5 cc would be on the syringe which is marked only in 5 cc increments.
Then he injects you with the assurance the "Statistically, over enough injections, it should be 1.5000 ccs".
So much for mathematics. I would much prefer a more precise syringe, myself.