Also, in yesterday’s Fin, Geoffrey Barker accused Abbott of going for the bogan vote (paywalled), where bogan is taken to mean ignorant. Leaving aside the class/cultural analysis implicit in the term “bogan”, which I think is wrong, the argument is the same as I made in my post on agnotology, as his characterization of Rudd as a technocrat, not really at ease with the kind of politics that includes demands for authenticity and so on. Coming back to “bogan”, the big issue in agnotology is not ignorance in the ordinary sense of the term (people who don’t know much about political issues, and don’t care to learn – that is certainly part of the stereotypical bogan image, and may perhaps be descriptive of the actual demographic groups commonly associated with the term, though I don’t know of any evidence of this).
The ignorance associated with climate change delusionism and other rightwing factoids is metacognitive and has much more to do with the Dunning-Kruger effect of overestimating one’s own competence. The classic example is the kind of person who eagerly circulates reports that there has been no statistically significant warming since 1995. The only information content in such a report is that the person doing the reporting doesn’t understand the concept of statistical significance[1], and therefore is incapable of assessing any issue involving statistical analysis, of which climate change is a prime example.
The stereotypical candidate, in relation to climate change, is that of a 50+ male[2] with a business background in engineering or some similar field where practical judgement is accorded more value than theoretical expertise, and where a willingness to push on regardless is an important element of success. Journalists and opinion columnists[3], accustomed to “mastering a brief” at short notice are also highly susceptible – lawyers who may actually have to master briefs involving technical issues seem mostly to recognise that this is the kind of problem where expert judgement is required, as does the more sensible kind of economist[4]
fn1. Note for pedants. A Bayesian statistician would say that confusion over the concept of significance reflects the logical problems of the concept and the underlying classical theory of statistics. But that only makes sloppy misuse of the concept even worse. I’ll have more to say on this soon, I hope.
fn2. A demographic group to which I belong
fn3. This one, too.
fn4. This one, too, I hope.
John Quiggin 
“Generally that includes a solid understanding of what statistical significance means”
So, I take it you understand that the claim “there has been no statistically significant warming since 1995” is merely an indication of the speaker’s ignorance of this meaning, and are happy to acknowledge that those on the “sceptical” side of the debate who parrot such claims don’t know what they are talking about.
@E.M.H I trust you can specify which part of the science behind the theory of Anthropogenic Global Warming is questionable. Very eager to see you provide even some links.
When you understand the science and all that underpins it then the tendency is indeed to look at deniers as er . . . less than competent and laugh a little behind your hand.
The problem with picking the data from 1995 has little to do with “statistical significance” ( well I suppose in a way it has, there isn’t enough data to get a decent result) and a lot to do with using short term data to model long term trends. But if you want to run a particular argument and there are enough suckers to fall for it; well; the goal is dreams into reality. I assume someone is paying for the deception.
Lets be honest, the whole “it ain’t getting warmer” thing has gathered it’s own momentum, it doesn’t really require professional input to keep the ball rolling. Look no further than some of the comments. Bet there isn’t an engineering qualification behind the lot of them.
Is it morally reprehensible, yes, but seriously, a lot of rot that comes out of the economic profession also. You next post details some of it. I don’t believe all of it is due to professional stupidity; I assume someone is paying.
You do however have to be careful dismissing the short term trend, as I pointed out, if you look at all previous events over the last million years the temperature goes up, reaches a peak and then falls very quickly.
“So what if anything do you think should be done?”
Well, if you look at the historical data, the last 10000 years have been pretty unusual. My view is the weather is in a particularly unstable state and if we move out of that state we are not going to get back there very easily. It very much looks as if the CO2 level is the controlling mechanism. The graph showing the temp and CO2 level follow each other pretty well. The the theory as to why the CO2 level matters looks pretty sound to me.
In my view we have two options; use our brains, control the level of CO2 and extend the current state further; or let it go and adapt to the changes. We will do one or the other, I suspect it will be the later.
‘well I suppose in a way it has, there isn’t enough data to get a decent result’
More precisely, whoever started this ball rolling picked 1995, precisely because it’s as far back as you can go from the present without having enough data to derive a statistically significant trend. Next year, they’ll either have to change the date or (more likely) move on to yet another talking point.
No John, they went back to 1995 because that is as far back you can go and get a line fit that has the temperature going down instead of up. Including a few more years changes the line direction, makes the result a little more robust, but from a statistical point of view is almost irrelevant. Twelve years or 20 years of data being used to represent data collected over 100’s of years, what does it matter, and as you have the 100’s of years of data why would you do it? Well unless you wanted to spread a bit of confusion.
Fit a second order polynomial to the last 30 years of data, I bet the future tail will be pointing down. More years, higher order polynomial, should be better hay? If the tail is pointing down the future prediction will have us freezing in 100 years.
“Next year, they’ll either have to change the date or (more likely) move on to yet another talking point.”
It has been a pretty cold winter in the Northern Hemisphere ( and it is the yearly average that matters when it comes to putting a point on this line) our summer hasn’t been that hot; we are now getting tropical weather in Victoria ( hot wet instead of hot dry).
I suspect you are going to have another year of pain.
My view is both groups are focusing on the wrong thing, in other words you have been sucker punched by those spreading confusion and deceit. The real evidence is a solid theory on why CO2 matters; and the close correlation between CO2 and planet temperature found in the ice cores.
My worry is the ice core results; every hot event has been immediately followed by a freeze. If we are lucky the hot event encouraged plant growth, the CO2 was removed and we froze. That won’t happen this time because we are still converting C and CH? into CO2.
What if a temperature rise flips the ocean currents and what if it takes another freeze to flip them back again. People banging on about global warming are going to look silly, going to suffer years of pain because the long term trend is up, while the short term trend is down. Better to talk about climate change, and focus on the science that matters.
And while I’m being a grumpy +50 engineer. Statistics is pretty much based on the random selection from a population and the tests of statistical significance generally tend to be based on the assumption that the population is normally distributed ( gaussian if your into hiding simple ideas behind the names of dead mathematicians). If you want to go a little deeper statistics uses a few values to represent a probability density functions; with the normal distribution done to death.
I find it difficult to see how any of the assumptions are met when your talking about the behaviour of a complex non linear system.
Why is EMH trying to challenge commenters here with his “deniars are those that are willing to ask questions, research and form their own opionions” vs “those on the left who accept the highly questionable science because it conforms nicely with their progressive, big goverment ideology” assertions rather than challenge the scientists at the CSIRO or BOM or NCAR or NASA or NOAA or Hadley CRU … or any relevant department of any leading university?
When it comes to the complex I don’t see anything wrong with looking to those with relevant expertise. If there were serious disagreements and competing schools of thought within climate science the layperson might have cause to step back and conclude there were serious fundamental issues to be resolved, but that isn’t the case with regard to climate – although there have been serious PR efforts to encourage people to believe that’s the case.
I am very suspicious of the conclusions of amateurs when they are the direct opposite of almost the entire body of actual experts.
When it comes to stuff that really matters I’ll take the experts over all the amatuers every time.
“No John, they went back to 1995 because that is as far back you can go and get a line fit that has the temperature going down instead of up.”
Have you looked at a graph of the data? Temperatures have risen since 1995, not fallen. They’ve been rising since 1970. The difference is that the increase since 1995 is (barely) statistically not significant, because there is not quite enough data to reject the null hypothesis of stability + random variation. (WordPress won’t let me post an image, but you can see it here
If you use data for the last forty years, the null hypothesis of no change in temperatures is strongly rejected in favour of the alternative of an increasing trend.
But, a better test in many ways is to look at the data since 1988 when the IPCC was established. Since there was already enough evidence to suggest the hypothesis of global warming was worth studying, this test is free of the problem of data mining (or, more pejoratively, cherry picking) evident in virtually everything done on the anti-science side of the debate.
I now have; yes your right (a bow down before you a humbler man), abuse of statistics has been taken to a new level. The null hypothesis test ( both t and z) assumes you are sampling a normal data distribution. Very hard to see how you would pin that assumption down without enough error terms to check the assumption ( and I don’t see 1988 as much better) in fact if you look at the graph it’s pretty obvious that a linear fit is not appropriate as the error term is far from random.
I would have gone for 1998 and shown that a linear fit has the temperature falling, and argued the global warming crowd are out of their tree. Opps been done, nothing new:
http://news.bbc.co.uk/2/hi/8299079.stm
Or perhaps gone back to 1995 and fitted a second order polynomial, that would have us freezing out but off in no time.
I’m not sure if you are being ironic here Charles. Obviously, picking 1998 ex post as a starting point is dishonest cherry picking, but marginally harder to nail than the absurd error involved in the 1995 claim. The delusionists would have been better advise to stick with that one.
As for higher-order polynomials I think Spencer of UAH has tested this approach to destruction.
As regards the normality assumptions, they are problematic as usual, but given the length of the warming trend, you can use robust or non-parametric tests and you’ll get the same answer. Only someone who hasn’t looked at the data will reject the hypothesis of an increasing trend.
No I just thinking about how I would run the denial campaign if it was my job, perhaps your right, 1998 would be too obvious. But I think I would go for the obvious.
Wasn’t Fielding sucked in by the 1998 story?
All that aside, we are talking about the output of a complex non linear system, the worst assumption you can make about such systems is that the output will be a linear response to the forcing function. Fitting linear functions to historic data makes that assumption.
I think fielding is a special case, to stay in parliament after the next election he has to find a block of votes. Climate change denialists represent such a block and in the past few seemed to be willing to collect. Abbott seems willing, so I don’t know where that leaves Fielding.
Charles I don’t think Fielding is a special case the no heating since 1998 argument gets trotted out by “sceptics” fairly regularly.
Water vapour caused one-third of global warming in 1990s, study reveals
“The research, led by one of the world’s top climate scientists, suggests that almost one-third of the global warming recorded during the 1990s was due to an increase in water vapour in the high atmosphere, not human emissions of greenhouse gases. A subsequent decline in water vapour after 2000 could explain a recent slowdown in global temperature rise, the scientists add……..
The new research, led by Susan Solomon, at the US National Oceanic and Atmospheric Administration, who co-chaired the 2007 IPCC report on the science of global warming, is published today in the journal Science, one of the most respected in the world…..
“What I will say, is that this [new study] shows there are climate scientists round the world who are trying very hard to understand and to explain to people openly and honestly what has happened over the last decade.
Solomon said: “We call this the 10, 10, 10 problem. A 10% drop in water vapour, 10 miles up has had an effect on global warming over the last 10 years.” Until now, scientists have struggled to explain the temperature slowdown in the years since 2000, a problem climate sceptics have exploited.
http://www.guardian.co.uk/environment/2010/jan/29/water-vapour-climate-change
Chris Warren #40 does not get my point #39 and does not seem interested in doing so.
Grim #46 does get the main point I was trying to make in the passage cited, which I should remind people was written (a) for publication in a newspaper whose readership includes a large number of people who we’ve yet to convince and (b) was written in an attempt to engage with someone who was seeking to argue in terms of probabilities and was suggesting that a 30% likelihood that AGW is happening or will happen is not really something to worry about.
Perhaps I could have chosen my words more carefully to avoid the phrase “dogmatically insist” and to avoid implying an equivalence between those who are convinced by the core science (which, for all practical purposes, includes myself) and the likes of Andrew Bolt, but to get one’s knickers in a twist over that phrase whilst ignoring my main argument is a serious misreading of my post – or, given Chris Warren’s background, a symptomatic reading of ym post.
@Tony G
And what, pray tell, determines the amount of water vapour in the atmosphere? Wouldn’t have anything to do with temperature, would it?
Tony’s comment illustrates the problem I’m talking about, and is typical of delusionists in general. Most of what they write requires the hypothesis that the entire scientific community (minus a few Galileos like Plimer and (!) Monckton) is engaged in a conspiracy to promote a bogus theory. But anytime the results of a study come out in a way that seems to suit their case (it doesn’t really, but we’re talking about people who don’t understand basic stats and can’t be bothered learning) they cite it as if peer-reviewed research was indeed the gold standard.
charles:
Not true for HadCrut3 any more (just). And it hasn’t been true for a long time with an estimator that includes the Arctic and Antarctic (GISS).
No doubt it will be a long time before the anti-scientists stop saying that it’s been cooling since 1998 because there are still some clowns claiming it’s been cooling for the past decade.
@sdfc
I remember Senator Fielding holding up the ‘inconvenient fact’ graph, that supposedly showed that warming had stopped whilst CO2 levels kept going up. If the rest of the graph (rather than the cherry picked small segment) was there at the same scale he’d have probably been about 3m up in the air!
Actually Fielding’s use of that graph is quite informative of how denialist arguments are framed – the selected bit of a selected graph (and don’t mention the fastest warming region on the planet being left out of that data set), or the complete passing over of short term variability vs longer term trends, or the other measures and indicators of climate change from ocean heat content and sea levels to changes in ice sheets and minimum sea ice levels, or the passing over of issues like lag time between emissions and effects on temperatures… etc.
When it’s about selected ‘facts’ in isolation rather than looking at every fact available – especially when the selections show the opposite to the whole – I think there is cause to get suspicious.
Chris
“variance adjusted local mean”? What variance have we accounted for in doing our adjustment (seriously I am curious if you know)? I assume it is something generated from the series before 1998.
Try the unadjusted global mean:
http://www.woodfortrees.org/plot/hadcrut3gl/from:1998/trend, note that it is down unlike 1997 and 1996 and 1995.
JQ said @20;
“to promote a bogus theory. ”
It is not I who is calling into question your scientific “theory”. In the above case “Susan Solomon, at the US National Oceanic and Atmospheric Administration, who co-chaired the 2007 IPCC report on the science of global warming,” who is .
JQ, it is delusional to say that the science is settled, especially when people like the IPCC’s co-chair Susan Solomon admit “there are climate scientists round the world who are TRYING VERY HARD TO UNDERSTAND and to explain to people openly and honestly what has happened over the last decade”. see my above link again.
Chris ‘O’
You have a degree and I don’t.
Can you please elaborate on what you mean by this?;
“And what, pray tell, determines the amount of water vapour in the atmosphere? Wouldn’t have anything to do with temperature, would it?”
@charles
You’ll have to look in Jones et al. (2001).
Yes, they can still say that. Any cherry-pick is a good cherry-pick. Of course, the trend is not significantly different from zero in either case with HadCrut3. And of course, that doesn’t stop the anti-scientists from saying things like “no warming since 1995” and also trying things like “it’s been cooling since 1998” even though statistical significance is absent in either case, especially with the cooling since 1998 claim.
@Tony G
In that case they’re trying to explain the weather because that’s the only thing we can detect a change in within a decade.
Pretty simple, the warmer the oceans and the atmosphere, the faster water evaporates from the oceans and the more water vapor the atmosphere can hold => more greenhouse effect from water vapor in the atmosphere. This feeds back into ocean and atmosphere temperatures so a positive feedback loop occurs. Fortunately that feedback loop is stable at existing temperatures but if the ocean ever exceeded 60°C then that loop is expected to go unstable.
Chris O’ Said;
“from water vapor IN the atmosphere.”
Chris, it is a misconception that the air holds water; air simply acts as a transporter of water vapour and is not a holder of it.
“The thermophysical properties of water-air mixtures encountered at atmospheric conditions are reasonably approximated by assuming they behave as a mixture of ideal gases. For many practical purposes the assumption that both components (air and water) behave independently of each other is reasonable. Therefore the physical properties of an air-water mixture can be estimated by considering the physical properties of each component separately.”
CHris O’
What you are saying put “pretty simpl[y]” is “the warmer the oceans and the atmosphere [get] the more water vapor [the] more greenhouse effect from water vapor in the atmosphere.”
You seem to be implying that if it gets hotter the more water vapor IN the atmosphere. I disagree with this assertion.
In an air-water vapour mixture the amount of water vapour can fall with rising temperatures. The amount of water vapour can also go up with a falling temperature. The amount of water vapour can stay the same or on some occasions, rise with increasing temperatures.
What drives the amount of water vapour in air is the absolute pressure. i.e.
Pressure 101.325kpa; T 70C = 50%
Pressure 101.325kpa; T 80c = 32.9%
Warmer temperatures do not necessarily translate to more water vapour in an air-water vapour mixture, Chris please explain how “warmer the oceans and the atmosphere” equate to “more greenhouse effect from water vapour in the atmosphere.” Considering warmer temperatures do not automatically equate to more water vapour in the atmosphere?
@Tony G
And how, pray tell, is that inconsistent with saying water vapor that water vapor is in the atmosphere?
It’s not an assertion, it’s an observed fact.
We’d be rather unlucky if it didn’t. Otherwise rainfall would take a major hit with a less humid atmosphere. It normally doesn’t start raining until humidity reaches 100%.
Chris O’Neill
It would be interesting to see your observed fact, but I can’t your link to work.
“You’ll have to look in Jones et al. (2001).”
This simple quote underlines many things wrong with the current debate.
1) The discussion started with the Chris asserting: “there are still some clowns claiming it’s been cooling for the past decade”.
And the proof was a link to a graph that uses a “variance adjusted mean”. I asked for details of what variance was used to adjust the mean ( I assume generalised least squares is being used in some way, I am curious as to how). Instead of an explanation I got from the person willing to call others clowns a link to a paper. A a paper that looks very interesting (based on the snippets I can find on the web); but:
2)The paper is behind a paywall, normally this wouldn’t be an issue as I would be studing something and be able to get at it through the library, but this year I am a normal joe. Interested or not I have to pay to find out why Chris feels he can assert that those using the raw value are fools ( given I got a link and not an explanation I suspect Chris is using blind faith in the hope that the faith is well placed), or, without reading the paper believe or dismiss Chris’s claim.
I’m not willing to pay, dismiss the claim or accept it, I am left ignorant and once again cursing the mess that scientific publishing has got itself into. Expecting people to have blind faith in journals ( peer reviewed or not) is not the way forward. Nor is calling people clowns because they are a little sceptical. Using sophisticated statistical methods does not make the answer right. To make a judgement you need more than the assertion that your a clown.
(minus a few Galileos like Plimer )
Interesting turn of phrase. The church has come out and apologised for what they did.
http://4thefirsttime.blogspot.com/2007/09/1992-catholic-church-apologizes-to.html
I wouldn’t be casting Plimer as Galileo as that would make him right and the his opponents wrong.
Sarcasm – useful for detecting dementia.
@charles
Sarcasm entirely warranted Michael when faced with comments like this one
“Nor is calling people clowns because they are a little sceptical. ”
If they would like to wait a while longer they will be called things far worse than clowns. Try imbeciles for example. Clowns is fairly mild I would suggest.
Alice
Interesting comment. So that is what it has come down to, name calling?
@charles
What is your opinion of Plimer’s contribution to the debate? Did you think JQ was being serious casting Plimer as a Galileo?
Tony G:
I should point out before citing the observed relationship between variations in atmospheric temperature and water vapor that it is a simple physical property of water that it’s vapor pressure above water in a confined space increases with temperature. There would have to be something pretty strange going on for the atmosphere not to follow this to some degree. Anyway here is the observed relationship between variations in atmospheric temperature and water vapor.
BTW, Tony G, how, pray tell, is saying that water vapor is in the atmosphere inconsistent with your following quote?
charles:
No, the linked graph was for the trend since 1998, not the last decade which is where the clown reference was made. If you check the graph for the last decade, you’ll find the unajusted mean has a clear positive trend. This is why I call people who still say it’s been cooling for the past decade, clowns. I think your misunderstanding underlines one thing wrong with the current debate. People are not careful to get their facts right.
@charles
Presumably, if you look at the paper you will find the answer or a reference to the technique used. If I was Jones, I too would, by this stage, be labeling these people clowns – an entirely appropriate appellation that could only be faulted for its charity.
Chris ‘O @ 36;
“it is a simple physical property of water that it’s vapor pressure above water in a CONFINED SPACE increases with temperature.”
Chris, are you classifying the atmosphere as a confined space?
“it is a simple physical property of water that it’s vapor pressure above water in a CONFINED SPACE increases with temperature.”
Tony G:
Anyone with at least normal intelligence might have guessed what I was implying from my sentence that followed the above:
“There would have to be something pretty strange going on for the atmosphere not to follow this to some degree.”
“something pretty strange going on for the atmosphere not to follow this to some degree.”
So explain to me Chris, “how, pray tell,” YOU can have our atmosphere behaving with”some degree” of a confined space?
Here is a question that someone with at least normal intelligence could answer with a simple yes or no;
Do you classify the atmosphere as a “confined space’? Yes or No.
Tony G:
Here is a question that someone with at least normal intelligence could answer with a simple yes or no;
Have you stopped beating your wife? Yes or No.
CHris O
Your lucky I cant retort, JQ seems to be blocking my posts Tony G.
Paranoia, I’m afraid, TG. I haven’t changed anything, and you’re not in the moderation queue, so you’ve probably used one of the Forbidden Words, like c@sino, or soCI@LISm.
Test
wasn’t working yesterday so I will try again today
Chris, just because you’re into “confined spaces” and “beating” doesn’t mean others share your passionate enthusiasm for such solitary endeavours.
It is understandable you need to change the subject, considering you are wrong to assert that warming simply equates to more water vapour in the atmosphere. You neglect the fundamental fact that the relative humidity is “pressure dependent” and so relative humidity can also rise or fall independent of temperature fluctuations.
See wiki relative humidity ‘pressure dependence’.
Are you also still trumpeting the success of the solar panel scheme? I’m still LoL on that one.
“the latest government green scheme to descend into farce, hot on the heels of the solar panel and insulation rebates.”
For the record Tony, on of my posts, — a response to Strocchi — went into moderation for 24 hours so I doubt it has anything to do with you. PrQ always says when he is moderating someone, so I assume it is technical.
@Tony G
The article you link to is over a month old and is mainly cheap shots rather than a sober analysis of the scheme. The interesting thing to note about all these green schemes is that there is a lot of unmet demand for these services. I had a house assessment done and it was very useful. The assessor was able to point out a few things I had over-looked, some of which I can do without spending much money. I didn’t apply for the loan because most of the other things that remain to be done are large projects I’m not ready to start yet.