Nic Lewis has a new post at Climate Audit that deals with some assumptions that went into IPCC AR4’s use of a uniform prior for estimating climate sensitivity.
He has shown it to be faulty, to the point that would normally be cause for a retraction, but this is Climate Science, where being wrong is simply a shade of grey, not black, nor white.
He writes:
Frame and Allen’s original graph (Figure 1) showed that use of a uniform prior in ECS gives a very high 95% upper bound for climate sensitivity, whereas a uniform prior in Feedback strength (the reciprocal of ECS) – which declines with ECS squared – gives a low 95% bound. A uniform prior in the observable variables (AW and EHC) also gives a 95% bound under half that based on a uniform in ECS prior; using a prior that is uniform in transient climate response (TCR) rather than in AW, and is uniform in EHC, gives an almost identical PDF.
Figure 1: reproduction of Fig. (c) from Frame and Allen ‘Observational Constraints and Prior Assumptions on Climate Sensitivity’, 2004 IPCC Workshop on Climate Sensitivity. Vertical bars show 95% bounds.
However, the Frame et al 2005 claim that high sensitivity, high heat uptake cases cannot be ruled out is incorrect: such cases would give rise to excessive ocean warming relative to the observational uncertainty range. It follows that Frame and Allen’s proposal to use a uniform in ECS prior when it is ECS that is being estimated does not in fact answer the question they posed, as to what the study tells one about ECS given no prior knowledge about it. Of course, I am not the first person to point out that Frame and Allen’s proposal to use a uniform-in-ECS prior when estimating ECS makes no sense. James Annan and Julia Hargreaves did so years ago.
…
The noninformative prior used for method 2 is shown in Figure 3. The prior is very highly peaked the in low ECS, low Kv corner, and by an ECS of 5°C is, at mid-range Kv, under one-hundredth of its peak value . What climate scientist using a Subjective Bayesian approach would choose a joint prior for ECS and Kv looking like that, or even include any prior like it if exploring sensitivity to choice of priors? Most climate scientists would claim I had chosen a ridiculous prior that ruled out a priori the possibility of ECS being high. Yet, as I show in my paper, use of this prior produces identical results to those from applying the transformation of variables formula to the PDFs for AW and EHC that were derived in Frame et al 2005, and almost the same results as using the non-Bayesian profile likelihood method.
Figure 3: Noninformative Jeffreys’ prior for inferring ECS and Kv from the (AW, EHC) likelihood. (The fitted EHC distribution is parameterised differently here than in my paper, but the shape of the prior is almost identical.)
…
Whilst my paper was under review, the Frame et al 2005 authors arranged a corrigendum to Frame et al 2005 in GRL in relation to the likelihood function error and the miscalculation of the ocean heat content change. They did not take the opportunity to withdraw what they had originally written about choice of priors, or their claim about not being able to rule out high ECS values based on 20th century observations. My paper[v] is now available in Early Online Release form, here. The final submitted manuscript is available on my own webpage, here.
The complete Climate Audit post is here: http://climateaudit.org/2014/07/30/paper-justifying-ar4s-use-of-a-uniform-prior-for-estimating-climate-sensitivity-shown-to-be-faulty/
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.”..but this is Climate Science, where being wrong is simply a shade of grey, not black, nor white.”
Being wrong, I’d add, is simply irrelevant, certainly where the IPCC is concerned. As long as the error supports hysterical alarmism. it’s not a problem. Critics of the most risible errors imaginable (as in Himalayan glaciers) instead of being taken seriously, are called practitioners of Voodoo Science and “deniers.” It’s not about being right. It’s about the message, and the perpetuation of their own influence.
What Myles Allen and his people getting things! Wrong never!
Myles Allen and David Stainforth were spot on with their prediction of up 11 degress celsius by the end of this century.
No wait it was their naff software that did it!
And all this proves what? To me he wrote this piece of obfuscation so that …….. ?
Latecommer
Look at the full post on Climate Audit. It explains how the IPCC relied on the Frame paper in their analysis of the possible range of climate senstivitiy.
Was this paper offered to Nature?
They would refuse it, but that would be getting them to dig themselves deeper and deeper into their hole…
I doubt this is a case of an error that requires retraction of the original paper. This seems more like a paper that proposes an improvement on a procedure that will affect a more accurate outcome. That kind of fine-tuning happens all the time in scientific circles without the need for retraction and is indeed how science progresses.
Justification for the use of a uniform prior probability density function (PDF) is lacking in this particular application of Bayes’ theorem. While the uniform prior PDF is uninformative it can be shown that non-uniform prior PDFs of infinite number are equally uninformative. Each of the many uninformative prior PDFs generates a different posterior PDF with consequential violation of the law of non-contradiction. That’s a logical no-no.
So if surface temperatures are less sensitive to GHGs than previously thought, where does all the excess heat go? Wouldn’t most of it go into the oceans, or to melting ice, which then leads to greater ocean acidification, thermal expansion, and sea level rise? Gee, I feel so much better now that these “errors” of the IPCC have been corrected.
They failed to apply: The Golden Rule of Forecasting: Be Conservative
Adding what Pamela Gray said, I’d like to point out that merely being wrong is not grounds for retraction of a paper. Generally retractions are the result of fraud or misconduct of some sort. Occasionally there will be a retraction for a paper’s major conclusions being wrong, but generally this only happens if the conclusions are based on gross misinterpretation of available data (such as using a statistical test that any reasonable scientist knows is inappropriate for what you’re testing), or if they’re based on a horribly faulty premise (Not just an unlikely premise, but one that there is no way it could be true).
Odd.
Sea level rise is not changing, ocean temperatures are not measurably changing, Antarctic sea ice is setting all-time record high levels while Arctic sea ice is within natural variations (within +/- 2 std deviations of its recent mean levels), and ocean acidification is not occurring (the oceans are buffered, and so are not changing pH levels.)
Maybe your theory about CO2 levels and temperatures is wrong?
The whole concept of a noninformative prior is a farce.
How can a prior distribution be noninformative when a choice must be made of the type of distribution and its parameters
Re: Rasey 4:02 pm
The paragraph beginning
The crime against objectivity should be outside the blockquote. It is not in the Wikipedia reference.
As Pamela Gray suggests science is a continuum where correcting errors is part of that continuum. However we are in a political climate where the “science is settled” and whether drought or flooding occurs in California it is due to the scientifically meaningless phrase “Climate Change”.
As far as retraction, it is a matter of degree; fine-tuning will not fix errors or an inappropriate premise.
RACookPE1978,
Sea levels are continuing to rise due to ice melt and thermal expansion of the oceans, which requires heat. Ocean temperatures are rising (where did you get the idea that they are not? See: http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/).
Rising water temperatures leads to acidification (and increases in pH are not negligible, but perhaps you don’t understand logarithmic scales). See this recent article for potential impacts: http://www.newsweek.com/ocean-acidification-alaskan-fisheries-alaska-crab-crabs-climate-change-alaska-261756
Also, it’s well known that Arctic sea ice is decreasing on decadal timescales; meanwhile, Antarctic sea ice may be expanding because Antarctic land ice is melting and refreezing when it reaches the ocean (since it is less dense than seawater and freezes at a higher temperature than seawater)… which adds to sea level rise, since as we all know, melting ice cubes don’t overflow your drink glass, but adding ice certainly may. 🙂
As long as there is a chance someone in academia, government or media will cite it as evidence of doom and gloom retraction must be out of the question.
Why don’t you try some “science” and give me some calculations for that: Give me the increased volume of seawater you claim is increasing due to “ice melt” and “thermal expansion” (when ocean temperatures have not risen but less than hundreds of one degree C since the mid 1970’s, and are not rising faster today (2114) than before.) Show me how much “ice” is needed to melt to cause your claimed increase in the rise of sea levels since 1980-1990. (Sea levels are increasing at the same rate as before the 1940’s – when air temperatures were higher than today’s values, but CO2 much less.)
No, rising ocean temperatures (which are as mentioned, very, very low values) do not cause an decrease in ocean pH. An imagined increase in dissolved CO2 might, but the oceans are strongly buffered, and will not change pH levels any greater than the usual day-to-night change seen every evening in every shallow water worldwide.
Try this “science” thingy, do some math for a change rather than spout your well-memorized propaganda: Arctic sea ice area is within 2 standard deviations of the recent (1970-1980) average level for this date. That means that Arctic ice levels are within the estimated mean for today’s dates recently – which is the only dates that matter in the Arctic. Last year’s ice, 2012’s sea ice, 2011, 2010 sea ice is long gone and has no more influence than Pinatubo.
Continued loss of Arctic sea ice from today’s levels from late August through March will only INCREASE heat loss from the ocean, since the little bit of increased SW radiation absorbed when the low angle sun’s rays hit an open Arctic ocean during those seven months is much more than made up by the increased LOSS of heat energy by conduction, convection, LW radiation into space, and evaporation when the Arctic is ice free rather than ice-covered.
And ice-freezing on the surface CANNOT cause a sea level rise. A Greek named Archimedes figured that out long before your so-called education began.
Let’s try that “science thingy” again: Just how much Antarctic land ice is needed to dilute the Antarctic ocean 500 and 900 kilometers AWAY from the Antarctic coast to cause an increase in sea ice coverage of 2.0 Million square kilometers of 2 meter thick ice? Come on: Give me the mass of “lost ice” required to spread out under 13 million square kilometers of “normal extents” sea ice, then continue to spread out to dilute the ocean water to freeze 2 million MORE kilometers of “excessive” Antarctic sea ice! Give me the distance from shore the edge of the Antarctic sea ice is right now (on average), and tell me how many cubic meters of water must be diluted for your fantasy to be valid.
Oh, by the way: There is no measured ice loss across the Antarctic continent, only a tiny bit on the West Peninsula near the coast. And Arctic temperatures per the DMI at 80 north this year have never even approached the “average” established since 1958: They have not been “above average even ONCE this summer (since the sun rose back near calendar day 120)! And winter air temperatures of -20 and -25 C (even if they are above average) don’t “melt” ice very well.
justsayin says:
RACookPE1978,
Sea levels are continuing to rise due to ice melt and thermal expansion of the oceans, which requires heat. Ocean temperatures are rising (where did you get the idea that they are not? See: http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/).
Wrong. That’s what you get for listening to the NODC. Here is a blink gif of the NODC’s “adjusting” the data. Don’t be naive when the gov’t asserts something. Be skeptical! The government has a vested interest in promoting scares. Don’t believe them. Be a skeptic.
Next, sea level rise is not accelerating. The models are wrong. The Envisat satellite measured sea level rise. This is what it found.
Next, ARGO buoys found that most areas in the deep ocean are cooling. That conflicts with the models. Who ya gonna believe? The models? Or the real world?
The fact is that sea levels have been rising about 1.3 inches per century since the LIA. There is no acceleration in sea level rise. In fact, everything being observed is normal.
RA Cook writes:
Sea level rise is not changing, ocean temperatures are not measurably changing, Antarctic sea ice is setting all-time record high levels while Arctic sea ice is within natural variations (within +/- 2 std deviations of its recent mean levels), and ocean acidification is not occurring (the oceans are buffered, and so are not changing pH levels.)
That is correct. You quote Newsweak. They are sensational, but not scientific. You write:
Rising water temperatures leads to acidification (and increases in pH are not negligible, but perhaps you don’t understand logarithmic scales).
That is wrong. There is no testable, measurable evidence of ocean “acidification”. The ocean intake pipe at the Monterey Bay aquarium tests for pH, and shows there is no change. No changes to ocean pH have been detected here, or here, or here since 1700. And the ocean has been much more acidic in the past. And regarding sea levels, here is a very good data base on the subject.
Next, the ocean “acidification” scare is alarmist nonsense. But don’t take my word for it. Visit this database and learn for yourself. If that is too much info for you, then read David Middleton’s excellent deconstruction of the pH scare here.
Next, you say:
…it’s well known that Arctic sea ice is decreasing on decadal timescales; meanwhile, Antarctic sea ice may be expanding because Antarctic land ice is melting and refreezing when it reaches the ocean (since it is less dense than seawater and freezes at a higher temperature than seawater)… which adds to sea level rise, since as we all know, melting ice cubes don’t overflow your drink glass, but adding ice certainly may.
Wrong again. Sea level rise has not accelerated, as documented above. The ocean heat content [OHC] is not rising fast. See the ARGO data above. Arctic ice was declining until recently, but total global ice cover is at its 30-year average. That is because the Antarctic [which is rarely mentioned by the alarmist crowd] has 10x the ice that the Arctic has, and that ice is increasing.
The climate Null Hypothesis states that nothing unusual or unprecedented is occurring, and the Null Hypothesis has never been falsified. Try to be skeptical. There are lots of self-serving connivers out there, trying to scare you for their own benefit. For the most part, they are lying.
Be skeptical!
“The climate Null Hypothesis states that nothing unusual or unprecedented is occurring, and the Null Hypothesis has never been falsified..
1. This is not a null. There is no quantifiable statement that can be falsified
2. It is not a null that is related to the core issue. to wit, c02 causes warming
I want readers to cast their minds back to the period leading up to the Copenhagen Climate Conference, and what we were being told about the IPCC’s 2007 4th Assessment Report.
It was drummed into us … “gold standard science” … “the science is settled” … “indisputable” … “based solely on peer reviewed literature”.
Visit the newspaper articles and media reports around the world at the time. From British Prime Minister Gordon Brown to Australian Prime Minister Kevin Rudd … from Al Gore to prince Charles … they were all swinging from the same branch.
Well, as we have seen since AR4 was released, it was all propaganda.
AR4 was all about those computer model derived trends reflected in those charts of rising temperature trends based on various rising human activity CO2 emissions scenarios. Remember?
And those charts have now all been debunked by none other than Mother Nature, which has revealed a flat global average temperature trend for almost 18 years.
Mother Nature has rendered IPCC AR4 obsolete. So much for “gold standard science” … “the science is settled” … “indisputable” … “based solely on peer reviewed literature”
“The climate Null Hypothesis states that nothing unusual or unprecedented is occurring, it’s all just natural climate variability”
“Natural climate variability and low climate sensitivity” is the null hypothesis to man made global warming (due to human emissions of CO2)..
dbstealey says:
July 30, 2014 at 6:56 pm
justsayin says:
RACookPE1978,
///////////////////////////
Further to dbstealey’s excellent comments putting facts in context, where does justsayin get the idea that Antarctic land ice is melting (see: justsayin says:July 30, 2014 at 4:57 pm)?
How can Antartic land ice be melting to any significant degree, since by definition, it is not in contact with the ocean (which is warm in relative terms) and therefore not subject to melting from below (powered by the relative warmth of the oceans), and air temperature over the continent is well below freezing? According to Wikipedia “The mean annual temperature of the interior is −57°C (−70°F). The coast is warmer. Monthly means at McMurdo Station range from −26°C (−14.8°F) in August to −3°C (26.6°F) in January.[8] At the South Pole, the highest temperature ever recorded was −12.3°C (9.9°F) on 25 December 2011.[9] ” See generally http://en.wikipedia.org/wiki/Climate_of_Antarctica
Of course, there are small areas around the coast which for relatively short periods of the year are warmer, and are above freezing, but significant melt from these areas cannot be happening since for most of the year they are below freezing. As Wikipedia observes: “Along the Antarctic Peninsula, temperatures as high as 15°C (59°F) have been recorded,[clarification needed] though the summer temperature is below 0°C (32°F) in most time.”
It seems to me that justsayin has got his facts sorely wrong.
Mervyn says:
July 30, 2014 at 8:07 pm
/////////////////
Quite so, but they have not had the guts to say that in AR5.
If the pause continues through to 2018/19, in my opinion, there will not be an AR6 since this will have to fess up and admit that the computer projections are departing too much from reality (they will by then be outside the 95% confidence level), and between now and 2018/19 it is probable that we will be seeing more and more papers suggesting ever lower figures for climate sensitivity.
Presently, the IPCC dodged the issue of sensitivity on the basis that there was no consensus. But should the pause continue through to 2018/19, it is likely that consensus will be that climate sensitivity is unlikely to be above 2 (or much above 2) and the bell curve will be showing significant area towards the 1.3 end.
And should it actually begin to cool between say 2015 and 2018/19, the data sets will show a negative straight linear trend for the entirety of this millenium (may not be significant, but negative nonetheless). The IPCC will face all sorts of problems should, if by then, the pause come have come to an end, and cooling actually begun.
There is a good chance that this farce will not survivve another 5 years. It is a question of how much damage will have been done before then. The only saving grace is that at Rio, China made it clear that it would do nothing before 2020, and the economic problems that the developed world have faced, have prevented the developed nations from rushing as quickly as they had intended towards decarbonising their economies. .
Steven Mosher:
You yet again display your arrogance, ignorance and stupidity when at July 30, 2014 at 7:13 pm you write saying in total.
Oh dear! Those assertions are completely wrong.
This is not the first time you have had this explained to you. Another of your recent excursion into displaying your ignorance of the scientific method was when you asserted there was no scientific Null Hypothesis until the 1930s when Fisher introduced the Null Hypothesis to statistics! But, in your arrogance you refuse to learn and, instead, proclaim your stupidity.
I explain the matter again, and I hope that this time you will read it and do that rare thing for you – learn from it.
The Null Hypothesis says it must be assumed a system has not experienced a change unless there is evidence of a change.
The Null Hypothesis is a fundamental scientific principle and forms the basis of all scientific understanding, investigation and interpretation. Indeed, it is the basic principle of experimental procedure where an input to a system is altered to discern a change: if the system is not observed to respond to the alteration then it has to be assumed the system did not respond to the alteration.
In the case of climate science there is a hypothesis that increased greenhouse gases (GHGs, notably CO2) in the air will increase global temperature. There are good reasons to suppose this hypothesis may be true, but the Null Hypothesis says it must be assumed the GHG changes have no effect unless and until increased GHGs are observed to increase global temperature. That is what the scientific method decrees. It does not matter how certain some people may be that the hypothesis is right because observation of reality (i.e. empiricism) trumps all opinions.
Please note that the Null Hypothesis is a hypothesis which exists to be refuted by empirical observation. It is a rejection of the scientific method to assert that one can “choose” any subjective Null Hypothesis one likes. There is only one Null Hypothesis: i.e. it has to be assumed a system has not changed unless it is observed that the system has changed.
However, deciding a method which would discern a change may require a detailed statistical specification.
In the case of global climate no unprecedented climate behaviours are observed so the Null Hypothesis decrees that the climate system has not changed.
Importantly, an effect may be real but not overcome the Null Hypothesis because it is too trivial for the effect to be observable. Human activities have some effect on global temperature for several reasons. An example of an anthropogenic effect on global temperature is the urban heat island (UHI). Cities are warmer than the land around them, so cities cause some warming. But the temperature rise from cities is too small to be detected when averaged over the entire surface of the planet, although this global warming from cities can be estimated by measuring the warming of all cities and their areas.
Clearly, the Null Hypothesis decrees that UHI is not affecting global temperature although there are good reasons to think UHI has some effect. Similarly, it is very probable that AGW from GHG emissions are too trivial to have observable effects.
The feedbacks in the climate system are negative and, therefore, any effect of increased CO2 will be probably too small to discern because natural climate variability is much, much larger. This concurs with the empirically determined values of low climate sensitivity.
Empirical – n.b. not model-derived – determinations indicate climate sensitivity is less than 1.0°C for a doubling of atmospheric CO2 equivalent. This is indicated by the studies of
Idso from surface measurements
http://www.warwickhughes.com/papers/Idso_CR_1998.pdf
and Lindzen & Choi from ERBE satellite data
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
and Gregory from balloon radiosonde data
http://www.friendsofscience.org/assets/documents/OLR&NGF_June2011.pdf
Indeed, because climate sensitivity is less than 1.0°C for a doubling of CO2 equivalent, it is physically impossible for the man-made global warming to be large enough to be detected (just as the global warming from UHI is too small to be detected). If something exists but is too small to be detected then it only has an abstract existence; it does not have a discernible existence that has effects (observation of the effects would be its detection).
To date there are no discernible effects of AGW. Hence, the Null Hypothesis decrees that AGW does not affect global climate to a discernible degree. That is the ONLY scientific conclusion possible at present.
Richard
“He has shown it to be faulty, to the point that would normally be cause for a retraction, but this is Climate Science, where being wrong is simply a shade of grey, not black, nor white.”
If the results are conform to the political established UNFCCC and IPCC then it’s political correct.