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Discussion > I'll bet not a lot of people know this

I found this site through Paul Homewood’s excellent notalotofpeopleknowthat website. Having read it several times now I have decided to share my ignorance with a wider audience.

In case it’s taken as some sort of spoof the original can be found here.


"GISS Surface Temperature Analysis

The Elusive Absolute Surface Air Temperature (SAT)

The GISTEMP analysis concerns only temperature anomalies, not absolute temperature. Temperature anomalies are computed relative to the base period 1951-1980. The reason to work with anomalies, rather than absolute temperature is that absolute temperature varies markedly in short distances, while monthly or annual temperature anomalies are representative of a much larger region.(Does this even make sense?) Indeed, we have shown (Hansen and Lebedeff, 1987) that temperature anomalies are strongly correlated out to distances of the order of 1000 km.

Q. What exactly do we mean by SAT?

A. I doubt that there is a general agreement how to answer this question. Even at the same location, the temperature near the ground may be very different from the temperature 5 ft above the ground and different again from 10 ft or 50 ft above the ground. Particularly in the presence of vegetation (say in a rain forest), the temperature above the vegetation may be very different from the temperature below the top of the vegetation. A reasonable suggestion might be to use the average temperature of the first 50 ft of air either above ground or above the top of the vegetation. To measure SAT we have to agree on what it is and, as far as I know, no such standard has been suggested or generally adopted. Even if the 50 ft standard were adopted, I cannot imagine that a weather station would build a 50 ft stack of thermometers to be able to find the true SAT at its location.

Q. What do we mean by daily mean SAT?

A. Again, there is no universally accepted correct answer. Should we note the temperature every 6 hours and report the mean, should we do it every 2 hours, hourly, have a machine record it every second, or simply take the average of the highest and lowest temperature of the day? On some days the various methods may lead to drastically different results.

Q. What SAT do the local media report?

A. The media report the reading of 1 particular thermometer of a nearby weather station. This temperature may be very different from the true SAT even at that location and has certainly nothing to do with the true regional SAT. To measure the true regional SAT, we would have to use many 50 ft stacks of thermometers distributed evenly over the whole region, an obvious practical impossibility.

Q. If the reported SATs are not the true SATs, why are they still useful?

A. The reported temperature is truly meaningful only to a person who happens to visit the weather station at the precise moment when the reported temperature is measured, in other words, to nobody. However, in addition to the SAT the reports usually also mention whether the current temperature is unusually high or unusually low, how much it differs from the normal temperature, and that information (the anomaly) is meaningful for the whole region. Also, if we hear a temperature (say 70°F), we instinctively translate it into hot or cold. But our translation key depends on the season and region; the same temperature may be 'hot' in winter and 'cold' in July, since by 'hot' we always mean 'hotter than normal', i.e., we all translate absolute temperatures automatically into anomalies whether we are aware of it or not.

Q. If SATs cannot be measured, how are SAT maps created?

A. This can only be done with the help of computer models, the same models that are used to create the daily weather forecasts. We may start out the model with the few observed data that are available and fill in the rest with guesses (also called extrapolations) and then let the model run long enough so that the initial guesses no longer matter, but not too long in order to avoid that the inaccuracies of the model become relevant. This may be done starting from conditions from many years, so that the average (called a 'climatology') hopefully (my bold) represents a typical map for the particular month or day of the year.

Q. What do I do if I need absolute SATs, not anomalies?

A. In 99.9% of the cases you'll find that anomalies are exactly what you need, not absolute temperatures. In the remaining cases, you have to pick one of the available climatologies and add the anomalies (with respect to the proper base period) to it. For the global mean, the most trusted models produce a value of roughly 14°C, i.e. 57.2°F, but it may easily be anywhere between 56 and 58°F and regionally, let alone locally, the situation is even worse."

Aren't the anomalies generated by taking the average of 30 years of SATS and comparing the current year's average of SATS to the 30 year average.

I'm not able to see how an average derived from crap SATS with guesses added and then compared to another average derived from crap SATS with guesses added is more accurate than the crap SATS.

What am I missing?

Apr 12, 2016 at 8:47 AM | Unregistered Commentergeronimo

What is your actual issue with this? There are numerous reasons for using anomalies, rather than actual temperatures. For example, imagine we average absolute temperatures. If we had perfect measurements with perfect sensors, this might be fine as a metric, even though averaging temperatures is not normally done, given that it's an intrinsic quantity. The problem, however, is that if you lose some data from a region that is very hot (relative to the average) or very cold (relative to the average) this can influence the average (unless you somehow account for this loss of data) (i.e., 30 + 20 + 10 + 0: average = 15; 30 + 20 + 10: average = 20). On the other hand, if we use anomalies for each region, then the value of the data for each region will be quite similar and if some data gets lost, it doesn't affect the average nearly as significantly (1 + 1 + 1 + 1: average = 1; 1 + 1 + 1: average = 1). See this for example.


Aren't the anomalies generated by taking the average of 30 years of SATS and comparing the current year's average of SATS to the 30 year average.

Only for a region, or a station. You have a 30 year average for each location. You then compute the anomaly for that location based on the current measurements (which has to correspond to the same time as the 30 year average) then you average all the anomalies to get you global (or hemispherical) temperature anomaly. You're average the anomalies for each region, not the temperatures for each region and then computing the anomaly.

Apr 12, 2016 at 9:14 AM | Unregistered Commenter...and Then There's Physics

I've been studying an online Philosophy course, and there was a concept explained which (for me) explains the ENTIRE climate debate. It is the idea of Underdetermination.

Underdetermination: Where the data that constitutes all the available evidence for a scientific theory is consistent with two or more theories, which differ with respect to the unobservable entities they recognise, the choice of theory is underdetermined by the data.

This is the problem with the climate debate. The alarmists insist that the observable data fits only one theory. The 'skeptical' viewpoint insists that their explanation is only one of a number of possible models which explain the data. This is why alarmists always get annoyed that the skeptical viewpoint is muddled or self-contradictory - it represents the set of theories which might explain the data - not a single theory.

The 'one theory' idea comes from science itself unfortunately, which always ranks hypotheses and marks the one at #1 as "the best we have, therefore the scientific truth for now". While this may have some utility for the machinations of science, it hassled to the mindset that all the other theories in the underdetermined set are incorrect.

Apr 12, 2016 at 9:45 AM | Unregistered CommenterTheBigYinJames


The 'skeptical' viewpoint insists that their explanation is only one of a number of possible models which explain the data.

Do you mean actual models that we can do actual calculations with, or do you mean ideas that might lead to models with which we could do actual calculations?

Apr 12, 2016 at 11:30 AM | Unregistered Commenter...and Then There's Physics

your actual issue with this?

"I'm not able to see how an average derived from crap SATS with guesses added and then compared to another average derived from crap SATS with guesses added is more accurate than the crap SATS.

What am I missing?"

I fully understand the use of anomalies and their reasons for using them, but can't see how an anomaly derived from two, not just crap, but in their own words valueless data sets can have any meaningful signal.

The reported temperature is truly meaningful only to a person who happens to visit the weather station at the precise moment when the reported temperature is measured, in other words, to nobody.

I'm assuming they're looking to get a meaningful signal out of the data, but the data sets look entropic to me, and there are two of them so they will be jointly entropic, so how could anyone expect to get a meaningful signal from them?

Apr 12, 2016 at 11:41 AM | Unregistered Commentergeronimo

A model is a tool used to express a hypothesis and examine the effects of the hypothesis. So I suppose I'm talking hypotheses now, rather than tools. As far as I know there is no 'skeptical' models (partly because, as I said before, there is no single skeptical hypothesis)

The true skeptical position (as opposed to the crackpot one) is that there are multiple hypotheses which could explain the data, the alarmist one is possible (perhaps even arguably the most probable), but there is a spectrum of hypothesis from 'nothing to see here, just natural' to 'we're frying ourselves' and the data we have underdetermines which of the theories is actually the most accurate.

Part of my annoyance with the alarmist position is not the genuine arguments about likelihood, playing it safe, scientific authority, etc., but its insistence that there is only one theory determined by the observed data. Forget 'denierspeak' for a moment, I'm as derisive of them as anyone of the alarmist side. The admission that the data could quite easily fit other less alarming hypotheses but on careful judgement probably doesn't would go a long way for me. It's this denial (ironically) of the usual scientific norms of competing theories with credibility weights attached that irks me.

Apr 12, 2016 at 11:49 AM | Unregistered CommenterTheBigYinJames

I don't think they're saying that the data is valueless. I think the argument is that using anomalies overcomes many of the issues that they're discussing. If we wanted to use actual temperatures, then there would need to be all sorts of definitions as to what was actually meant, and when and where the measurements were taken. Using anomalies largely overcomes these issues. If two regions took measurements at different times of the day it would certainly matter with respect to reporting the actual temperature, but doesn't really matter if all you're interested in is the anomaly. If two regions took measurements from slightly different altitudes, this would might influence the absolute temperature but not the anomaly (I'm talking about a different of metres, rather than kms, of course).

Apr 12, 2016 at 11:50 AM | Unregistered Commenter...and Then There's Physics


but its insistence that there is only one theory determined by the observed data.

Maybe people shouldn't insist that there is only one, but there is a vast amount of evidence that supports the basic hypothesis associated with anthropogenically-driven warming.


The admission that the data could quite easily fit other less alarming hypotheses but on careful judgement probably doesn't would go a long way for me.

I don't think it is quite easy and I think a lot of careful judgement has gone into this. If you read the actual literature, it is mostly very careful.

Of course, the current scientific position still includes the possibility that climate sensitivity could be low, that we could emit a lot more GHGs without warming much, that the water cycle will not accelerare much, and that extreme events will not increase in intensity and frequency in any particularly significant way. However, it also include that climate sensitivity could be high,...... Also, the best estimates are somewhere in the middle of this (i.e., a TCR of around 1.5 - 2C, and ECS of around 2.5 - 3C, water vapour increasing at 7%/K, and precipitation increasing at 2%/K,.....)

To me there is a vast difference between disputing the basics of the science, or disputing the possibility that the consequence could be severe, and accepting this but making an argument as to why fossil fuels should still dominate our energy provision and should do so without any real investment in carbon storage or negative emission technology.

Apr 12, 2016 at 11:59 AM | Unregistered Commenter...and Then There's Physics

BYIJ - yes. One of the things that characterises 'climate science' as being different from science is that there can be only one true climate theory (the lack of understanding of numerous of its facets notwithstanding). Its acolytes frequently express the idea that if you can't come up with an alternative (preferably peer-reviewed) that explains things better, you have to accept the existing hypothesis as being the truth.

In the paleo thread, EM expressed his belief that there can only be one currently valid theory (of whatever).


.. that climate sceptics can play the " uncertainty" card OR the "the past was warmer" card. Since they contradict each other you cannot play both. [Entropic man]

Why not? If it is not certain which one is correct, both can be put on the table as two alternative (even if exclusive) hypotheses.

Mar 28, 2016 at 9:40 AM Martin A

Alan Kendall put my observation on a firm footing as follows:

Martin A

I offer support for your last point. Geological evidence commonly is insufficient to reach definitive answers (hence this entire thread). Not all the critical evidence required to make determinative conclusions may be preseved. Accordingly geologists may hold to several hypotheses simultaneously to explain the same set of facts. This methodology was first formulated by T.C.. Chamberlin in 1889 (published in 1890) as "The Method of Multiple Working Hypotheses". Knowledge of this seems largely confined to geology, but clearly reflection suggests it is in operation in the cutting edge of most sciences. Clearly not practiced by computer modellers, however.

Chamberlin's methodology ought to be force fed to all climate scientists.
Mar 28, 2016 at 10:13 AM Alan Kendall

Apr 12, 2016 at 12:04 PM | Registered CommenterMartin A

To me there is a vast difference between disputing the basics of the science, or disputing the possibility that the consequence could be severe, and accepting this but making an argument as to why fossil fuels should still dominate our energy provision and should do so without any real investment in carbon storage or negative emission technology.

Yes, I agree there is a vast difference, but although many people do conflate these, not everybody does.

I tend to stay out of the energy discussions here for that reason - I am in general a supporter of getting off fossil fuels as quickly as we can - a general supporter of clean energy development - even if there is not a great economic driver for this. I am not an "economic alarmist". I think it's worth paying more for cleaner energy.

There are multiple reasons why getting away from fossils is a good idea, one of them being the potential climatic impact of continuing their use (whatever the magnitude of this turns out to be), although I think there are more pressing reasons to do so (geopolitics, local pollution and health).

My interest (and the basis of my 'siding' with the skeptic camp) is my nature forbids me from partaking in dogmatic bullying. Even if someone is wrong (and there is a lot of rubbish spouted on both sides of this debate) then they must be debated, argued and shows the error of their ways. I can understand why an individual scientist here has not enough hours in the day to do so (I've wasted too many heartbeats in fruitless discussion with the Dungs of this world) but Science with a capital S has a duty to do so. Like politics, Science is only sustained on the sweat of the brows of the people working and generating taxes, so it has a duty to take their views into consideration even if it thinks they are morons.

Instead it has shirked this responsibility. It has resorted to name calling (deniers) and my 'underdog' gene kicks in. As I've said to EM here, I'm probably 99% of the opinions you are on climate, and people are stupid, and uninformed, and it is a thankless, unrewarded and painful task to being humanity up to speed, but that is what needs to be done. Individual scientists who don't have the gumption to do it should keep their mouths shut.

IMO, of course.

Apr 12, 2016 at 1:11 PM | Unregistered CommenterTheBigYinJames


my nature forbids me from partaking in dogmatic bullying.

Interesting, I wouldn't have guessed from this thread.

Let me make a point (it was going to be a question, but ended up rather convoluted). I'm a scientist (and this isn't intended as some kind of appeal to authority) and I think my general views are similar to many other scientists, both in physics/astronomy and climate science. My job/role is to do research and to present the results of that research in papers, at conferences, and - sometimes - to the public. Whether or not my results turn out to have merit or not (and everything is wrong in some respect, so I just mean helps to improve understanding) doesn't really depend on how I'm perceived. I can be nice, or not. I can speak out, or be quiet. I can get involved in contentious discussions on blogs where I might get frustrated, or not. At the end of the day, the evidence will speak for itself.

And yet, a great deal of the online climate debate revolves around apparent behaviour, as if this tells us something about the actual science. However, whether or not there are potentially severe consequences from emitting more and more CO2 into the atmosphere is not going to depend on whether or not some scientists weren't as nice as maybe they should have been. It won't depend on whether or not some people were called "deniers" or "alarmists". It won't even depend on whether or not some papers were poor and shouldn't have been published. It will really just depend on how our cimate responds to increasing anthropogenic forcings. Also, if it does have severe consequences, excusing our inaction on the fact that some people were called "deniers" will seem rather pathetic, IMO.

IMO, if people could focus more on the science and less on the personalities, the debate would be much improved. That's not to say that scientists couldn't improve/change how they engage publicly, but many have little training in doing so and little time to get such training. Many scientists are not trying to market their research, they're simply trying to explain it to those who might be interested. Some can get rather frustrated by the responses and may say things that maybe they shouldn't. However, they are first and foremost researchers who happen to engage publicly, not politicians who are trying to convince others to vote for them. They're also only human.

Apr 12, 2016 at 1:32 PM | Unregistered Commenter...and Then There's Physics

Interesting, I wouldn't have guessed from this thread.

Aw bless, you remembered it, and had it handy for likning. It's amusing you consider that as me bullying you - instead of me calling out the bully, but hey ho.

Some can get rather frustrated by the responses and may say things that maybe they shouldn't.

And that's it, exactly.

Unfortunately, when someone on the establishment side says something that perhaps they shouldn't then it sets the tone that the establishment position takes. It becomes fair game for clueless journalists, eco-warriors, anyone with a single interest agenda to jump on and use to beat someone up on. It's OK to use terrible language, because the scientists do it, and since science is the pinnacle of human endeavour then it must be ok in absolute terms to do so.

If one scientist says one person is working for Big Oil, whether it is true or just a piqued outburst, then it becomes ok for every official and unofficial outfit to throw out the same accusations about anyone who happens to annoy them.

Science has a duty which it is shirking at the moment, and to fall back on human fallibility as an excuse is just that - an excuse. I expect better.

Apr 12, 2016 at 1:44 PM | Unregistered CommenterTheBigYinJames


It's amusing you consider that as me bullying you - instead of me calling out the bully, but hey ho.

six of one? (although I'm not quite sure who I've been bullying) Also, I just said "I wouldn't have guessed". Now that you've told me, I know ;-)


Science has a duty which it is shirking at the moment, and to fall back on human fallibility as an excuse is just that - an excuse. I expect better.

And you can expect whatever you like. My point is that it's not going to change reality. Also, scientists are human and no amount of expectation on your part (or anyone else's) is going to change that. That's why - ultimately - we should trust the scientific method, not individual scientists, or individual studies. As I've already said, how our climate will respond to increasing anthropogenic forcings is not going to depend on whether or not the behaviour of some scientists was not what you would have expected.

Apr 12, 2016 at 1:54 PM | Unregistered Commenter...and Then There's Physics

As I've already said, how our climate will respond to increasing anthropogenic forcings is not going to depend on whether or not the behaviour of some scientists was not what you would have expected.

And likewise it's not going to depend on citations, peer reviews, editorial sackings, fudged data etc.
What's your point caller?

I don't 'trust' the scientific method - it has proven to be the most useful tool we have found yet for explaining the universe, and on that basis I will continue to use it until we find something better.

But because it is conducted by fallible people, the scientific method embodies some of their flaws, and several of its flaws are combining in the area of climatic physics - lack of competing teams, immaturity of the physics, poor historical observations, politicisation of the outcomes, cause corruption of the participants, and as you say, human nature. This is causing a hiccup in the normal flow of scientific research which is very damaging. Anyone area which promotes a scientific fact by consensus is a very sickly science indeed.

It's not really the business of Joe Pleb, of Creationistville USA to try to critique the science, but because there is nobody in the establishment doing it, it leaves a void which can be filled by... well, we know what by. This is bad. it's bad for everyone, not just science.

So you may be brushing off my concerns, that my desire for integrity within science is not going to happen just because I want it. It's your funeral. You're opening the door for the sort of mediaevalist nonsense that seems to be on the rise. It's your funeral.

Unfortunately it's also ours. So it's not just an expectation ,it's a demand.

Apr 12, 2016 at 2:09 PM | Unregistered CommenterTheBigYinJames


So you may be brushing off my concerns, that my desire for integrity within science is not going to happen just because I want it. It's your funeral. You're opening the door for the sort of mediaevalist nonsense that seems to be on the rise. It's your funeral.

Now you're putting words in my mouth. Let me know if you really want to have this discussion, but if you're going to put words in my mouth, then I'm going to assume that you don't and that your desire for integrity applies to others, but not yourself.


Unfortunately it's also ours. So it's not just an expectation ,it's a demand.

Demand away. It still doesn't change my overall point.

Apr 12, 2016 at 2:15 PM | Unregistered Commenter...and Then There's Physics

First of all, let me agree with ATTP's statement "Let me make a point etc ..." — Just so we know where we are starting from!
In fact I pretty much agree with the rest of it as well, which will probably start to worry him!
My position has always been much like BigYin's — I would be much happier to accept the possibilities of AGW if its proponents weren't so bloody arrogant about it. Either agree 100% with the Message or be vilified. In my experience in other fields that is usually a sure sign that the evidence for the Message is weak!
Remember Carl Sandburg"s advice:

If the facts are against you, argue the law. If the law is against you, argue the facts. If the law and the facts are against you, pound the table and yell like hell.

I made the argument yesterday, in response to ATTP, that assuming that the climate change "debate" (which we all know was decided before any of us were allowed to join it) was all about science is a fallacy. There are indeed several hypotheses out there but only one that persistently lays the blame for modern warming on CO2, and to all intents and purposes on nothing else.
This is the one that has been adopted by the climate establishment even though there is strong evidence that CO2 lags temperature by anything up to 800 years and that the correlation between CO2 and temperature during the 20th century only works if you cherry pick the data.
In most other branches of science (including, I imagine, astrophysics?) these anomalies would be sufficient to at least open the door to alternative hypotheses.
I agree that scientists are human and fallible which is one more reason why the declarations of infallibility coming out of the climate establishment are not acceptable. And sceptics are quite happy to accept the scientific method which starts from the point that what the climate has been doing for the last several millennia has been only very marginally influenced by human activity and that any changes that are occurring now are likewise only very marginally influenced by humanity in the absence of very strong evidence to the contrary. And computer models are not evidence and running computer programs is not experimentation.
And to echo BigYin's last point, the outcome of the climate debate, regardless of what happens to the climate, is going to have a profound effect on virtually the whole of humanity because — like it or not — it has been "stolen" by the eco-extremists and by the control freaks at the UN and various other socio-political activists and if the scientific establishment is not able or willing to argue against the abuse of their science and the media have become too dim or too venal to pay attention then it is going to have to be done by bloggers.
Many of whom would much rather be doing a host of other things which are a lot more fun.

Apr 12, 2016 at 2:32 PM | Registered CommenterMike Jackson

Alarum scarum,
Toil and trouble;
All that fear
Was just a bubble.
=============

Apr 12, 2016 at 2:43 PM | Unregistered Commenterkim

Demand away

Thus this blog.

BTW, accusations of not being serious simply because I refuse to accept your terms is cowardice.

Apr 12, 2016 at 3:04 PM | Unregistered CommenterTheBigYinJames


BTW, accusations of not being serious simply because I refuse to accept your terms is cowardice.

I suggested you weren't being serious because you were misrepresenting what I said, as you've just done again. FWIW, it is hard to take someone's demands for integrity seriously when they appear lacking in it themselves.

Apr 12, 2016 at 3:11 PM | Unregistered Commenter...and Then There's Physics

And there we go. ATTP's modus operandi....

*cluck cluck*

Apr 12, 2016 at 3:36 PM | Unregistered CommenterTheBigYinJames

"I don't think they're saying that the data is valueless."

"Q. What exactly do we mean by SAT?

A. I doubt that there is a general agreement how to answer this question...

"Q. What do we mean by daily mean SAT?

A. Again, there is no universally accepted correct answer."

"Q. If the reported SATs are not the true SATs, why are they still useful?

A. The reported temperature is truly meaningful only to a person who happens to visit the weather station at the precise moment when the reported temperature is measured, in other words, to nobody. However, in addition to the SAT the reports usually also mention whether the current temperature is unusually high or unusually low, how much it differs from the normal temperature, and that information (the anomaly) is meaningful for the whole region..."

Q. If SATs cannot be measured, </b?how are SAT maps created?

A. This can only be done with the help of computer models, the same models that are used to create the daily weather forecasts. We may start out the model with the few observed data that are available and fill in the rest with guesses (also called extrapolations) and then let the model run long enough so that the initial guesses no longer matter, but not too long in order to avoid that the inaccuracies of the model become relevant. This may be done starting from conditions from many years, so that the average (called a 'climatology') hopefully (my bold) represents a typical map for the particular month or day of the year.

You're technically right, they're not saying they're valueless - I said that - they're saying they can't be measured, which I translated into "valueless" in my pedantic way.

They go on to say they produce SAT maps presumably using the measurements from the unmeasurable data, and making further "guesses" - their word. I know they run algorithms to iron out known problems with the weather stations and adjust it accordingly but they have to use the "unmeasurable" (i.e. entropic) data from the SATs.

Apr 12, 2016 at 3:38 PM | Unregistered Commentergeronimo

BYJ,
What you are describing quite well in multiple posts on this thread regarding how the climate concerned behave is something like a social mania, not a well informed scientific movement.

ATTP,
You have the gall to complain about bullying- that is at once pathetic and hilarious.

Apr 12, 2016 at 4:15 PM | Unregistered Commenterhunter


You have the gall to complain about bullying- that is at once pathetic and hilarious.

Firstly, I wasn't. I was simply indicating surprise. Secondly, maybe you can tell me who I've been bullying. So, who do I bully and how?

Apr 12, 2016 at 4:31 PM | Unregistered Commenter...and Then There's Physics

ATTP,
Your pathetic website is all the evidence needed.

Apr 12, 2016 at 5:23 PM | Unregistered Commenterhunter


Your pathetic website is all the evidence needed.

So, no actual examples? Just my website? What about it? Anything specific, or do you simply object to other having websites that say things with which you disagree?

Apr 12, 2016 at 5:46 PM | Unregistered Commenter...and Then There's Physics