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« Met insignificance | Main | Significantly Met O££ice - Josh 223 »

Met Office admits claims of significant temperature rise untenable

This is a guest post by Doug Keenan.

It has been widely claimed that the increase in global temperatures since the late 1800s is too large to be reasonably attributed to natural random variation. Moreover, that claim is arguably the biggest reason for concern about global warming. The basis for the claim has recently been discussed in the UK Parliament. It turns out that the claim has no basis, and scientists at the Met Office have been trying to cover that up.

The Parliamentary Question that started this was put by Lord Donoughue on 8 November 2012. The Question is as follows.

To ask Her Majesty’s Government … whether they consider a rise in global temperature of 0.8 degrees Celsius since 1880 to be significant. [HL3050]

The Answer claimed that “the temperature rise since about 1880 is statistically significant”. This means that the temperature rise could not be reasonably attributed to natural random variation — i.e. global warming is real.

In statistics, significance can only be determined via a statistical model. As a simple example, suppose that we toss a coin 10 times and get heads each time. Here are two possible explanations.

  • Explanation 1: the coin is a trick coin, with a head on each side.
  • Explanation 2: the coin is a fair coin, and it came up heads every time just by chance.

(Other explanations are possible, of course.)

Intuitively, getting heads 10 out of 10 times is very implausible. If we have only those two explanations to consider, and have no other information, then we would conclude that Explanation 1 is far more likely than Explanation 2.

A statistician would call each explanation a “statistical model” (roughly). Using statistics, it could then be shown that Explanation 1 is about a thousand times more likely than Explanation 2; that is, statistical analysis allows us to quantify how much more likely one explanation (model) is than the other. In strict statistical terminology, the conclusion would be stated like this: “the relative likelihood of Model 2 with respect to Model 1 is 0.001”.

A proper Answer to the above Parliamentary Question must not only state Yes or No, it must also specify what statistical model was used to determine significance. The Answer does indeed specify a statistical model, at least to some extent. It states that they used a “linear trend” and that the “statistical model used allows for persistence in departures using an autoregressive process”.

If you are unfamiliar with trending autoregressive processes, that does not matter here. What is important is that HM Government recognized, in its Answer, that some statistical model must be specified. There is, however, still something missing: is their choice of statistical model reasonable? Might there be other, more likely, statistical models?

(There is also a minor ambiguity in the Answer, because there many types of autoregressive processes. The ambiguity is effectively resolved in a related Question, from 3 December 2012, which discussed “autoregressive (AR1) processes” [HL3706]; other Answers, discussed below, confirmed that the process was of the first order.)

I found out about the Question (HL3050) put by Lord Donoughue via the Bishop Hill post “Parliamentarians do statistical significance”. I then discussed the choice of statistical model with Lord Donoughue. I pointed out that there were other models that had a far greater likelihood than the trending autoregressive model used by the Answer. In other words, the basis for the Answer to the Question was untenable.

Moreover, I had published an op-ed piece discussing this, and related issues, in the Wall Street Journal, on 5 April 2011. The op-ed piece includes a technical supplement, which describes one other statistical model in particular: a driftless ARIMA(3,1,0) model (again, unfamiliarity with the model does not matter here). The supplement demonstrates that the likelihood of the driftless model is about 1000 times that of the trending autoregressive model. Thus the model used by HM Government should be rejected, in favor of the driftless model. With the driftless model, however, the rise in temperatures since 1880 is not significant. In other words, the correct Answer to the Question (HL3050) might be No.

Lord Donoughue then tabled a Parliamentary Question asking HM Government for their assessment of the likelihood of the trending autoregressive model relative to the driftless model. HM Government did not answer. Lord Donoughue asked a second time. They did not answer. He asked a third time. Again they did not answer. He then asked a fourth time.

A Parliamentary Question that has been tabled in the House of Lords is formally answered by HM Government as a whole. In practice, HM Government assigns the Question to a relevant ministry or department. In our case, the Questions have been assigned to the Department of Energy and Climate Change; the designated minister is the Parliamentary Under Secretary of State, Baroness Verma. Verma obtains answers from the Met Office. The person at the Met Office with final authority is the Chief Executive Officer, John Hirst. In practice, Hirst delegates authority to the Chief Scientist at the Met Office, Julia Slingo. Thus, it is actually Slingo who was refusing to answer the Parliamentary Questions, with Hirst and Verma backing her (perhaps without thinking).

I have had a few e-mail exchanges with Slingo in the past. Slingo has never really addressed the issues that I raised. Instead, she has replied largely with rhetoric and a display of gross ignorance about undergraduate-level statistics; for an example, see the Bishop Hill post “Climate correspondents”. Thus, I decided that trying to talk directly with Slingo about the Parliamentary Questions would be a waste of time. Hence, I tried talking with Hirst. My message to Hirst included the following.

Last week, Lord Donoughue tabled Parliamentary Question HL6132, about statistical models of global temperature data. HL6132 is essentially the same as HL5359, which the Met Office refused to answer. The Met Office Chief Scientist does not have the statistical skills required to answer the Question; there is, however, at least one scientist at the Met Office who does have the skills—Doug McNeall. I ask you to ensure that the Question is answered.

Doug McNeall is a statistician. He and I have had cordial e-mail discussions in the past. In particular, after my op-ed piece in WSJ appeared, on 12 August 2011, McNeall sent me an e-mail stating that the trending autoregressive model is “simply inadequate”. Indeed, that would be obvious to anyone who has studied statistical time series at the undergraduate level. Note that this implies that a statistician at the Met Office has stated that the Answer given to the original Parliamentary Question (HL3050) is unfounded.

Lord Donoughue’s fourth Question was, as before, refused an answer. Afterwards, I received the following message from Hirst.

I would like to assure you that the Met Office has not refused to answer any questions. The questions you refer to were answered by Baroness Verma, Parliamentary Under-Secretary of State at the Department of Energy and Climate Change.

I note that in her response to HL5359 and HL6132, and a number of other questions from Lord Donoughue, Baroness Verma has offered for him to meet officials to discuss this and related matters in more detail.

Afterwards, Lord Donoughue asked the question a fifth time. And I sent the following message to Hirst.

I do not know whether your message is serious or just your way of telling me to get lost. In case of the former, some elaboration follows.

The question that Lord Donoughue has been asking requires the calculation of a single number. The calculation is purely arithmetical: there is no opinion or judgment involved (nor is background in climate needed). Furthermore, the calculation is easy enough that it could be done in minutes, by someone with the appropriate statistical skills. You could think of it as being similar to finding the total of a column of integers.

The number that Lord Donoughue is asking for is 0.001, according to my calculation. (Yes, it is that simple.) Lord Donoughue, though, would like the number calculated by an official body. He therefore tabled Parliamentary Questions asking HM Government for the number.

Lord Donoughue has now received Written Answers to four such Parliamentary Questions: HL4414, HL5031, HL5359, HL6132. None of those Answers give the number. Instead, the Answers make excuses as to why the number is not given. The main excuse seems to be that the number is not important. The importance of the number, however, is a separate issue: even if the number has no importance at all, the arithmetical calculation can still be done, and the number can still be given.

HM Government has been relying upon the Met Office, to supply them with the number; the Met Office has refused to do this. In other words, the Met Office has refused to answer the question—contrary to the claim in your message. What reason does the Met Office have for refusing to supply the number? The required time would be less than the amount of time that the Met Office has spent in refusing.

Parliamentary Questions have a history going back centuries. I do not have expertise in this area, but it is my understanding that HM Government is obliged to either provide an Answer to a Question or else give a valid reason for not providing an Answer. The refusal of the Met Office to supply the number would thus seem to be leading to a violation of a centuries-old parliamentary convention. Indeed, I have now talked with other members of the House of Lords and the Commons about this: there is real concern, and apparently also by parliamentary officials.

Lord Donoughue has now asked for the number a fifth time. The tabled Question is as follows (HL6620).

To ask Her Majesty’s Government … whether they will ensure that their assessment of [the number] is published in the Official Report; and, if not, why not.

The Answer is due by April 12th. My hope is that if the Met Office continues to refuse to supply the number, HM Government will get the number from elsewhere.

There was no immediate response to that. I did, however, receive an invitation from Doug McNeall to visit the Met Office and discuss the statistics of trends in global temperatures. I replied as follows.

Kind thanks for this. In principle, such a meeting would surely be valuable. The Met Office, however, is refusing to answer a simple arithmetical question, and moreover, is presenting dishonest reasons for doing so. Given that, I do not have confidence that discussion could be in good faith.

Hence, I respectfully decline. If the Met Office supplies the number, I would be happy to discuss this further.

A week later, the fifth Question (HL6620) was answered as follows.

As indicated in a previous Written Answer given … to the noble Lord on 14 January 2013 (Official Report, col. WA110), it is the role of the scientific community to assess and decide between various methods for studying global temperature time series. It is also for the scientific community to publish the findings of such work, in the peer-reviewed scientific literature.

Thus, in the opinion of the Met Office, Parliament has no right to ask scientific questions of government scientists.

A few days later, I received the following message from Hirst.

I’m sorry for the delay in replying; I have been away from the office.

I’m sorry if my previous e-mail gave you the impression I did not wish to discuss this matter further. That was not my intention. Indeed, if you are not satisfied with the answers that have been given to Lord Donoughue’s Parliamentary Questions, I would be more than happy for us to debate your concerns, as part of a detailed scientific discussion about the statistical modelling of global mean temperatures.  

I understand Doug McNeall has offered to arrange a meeting with you and other Met Office scientists who work in this area. I feel this would be a sensible way forward and, although our views may differ in some respects, can assure you we would approach this meeting in good faith.

I look forward to hearing from you.

Hirst is clearly supporting the obstructionism. I decided that there was no point in replying.

Under the rules of Parliament, the person with responsibility for a Parliamentary Question is the government minister who delivers the Answer. In our case, that minister is Baroness Verma. According to the Companion to the Standing Orders and Guide to the Proceedings of the House of Lords, §4.68 Ministerial Responsibility, “Ministers should be as open as possible with Parliament, refusing to provide information only when disclosure would not be in the public interest” and “Ministers who knowingly mislead Parliament will be expected to offer their resignation to the Prime Minister”.

Lord Donoughue then sent a strongly-worded letter to Under Secretary Verma, citing the section on Ministerial Responsibility, and adding “I trust we will not reach that point since you are clearly not behind the wilful refusal to answer the Question”. Indeed, Verma seems to have been trusting that the Answers supplied to her by the Met Office were written in good faith.

Then Lord Donoughue asked the question a sixth time (HL62). The Answer, this time, included the relative likelihood. The full Answer (excluding footnotes) was as follows.

There are many ways to analyse time series, including the use of physical and statistical models. The relevance of any technique depends on the question asked about the data. The Met Office has compared the likelihood of the two specified models for fitting the three main independent global near-surface temperature time series (originating from UK Met Office and NASA and NOAA in the US), using a standard approach.

The statistical comparison of the model fits shows the likelihood of a linear trend model with first-order autoregressive noise in representing the evolution of global annual average surface temperature anomalies since 1900, ranges from 0.08 (Met Office data) to 0.32 (NOAA data), relative to the fit for a driftless third-order autoregressive integrated model. The likelihood is 0.001 if the start date is extended back for example to 1850 (Met Office data). These findings demonstrate that this parameter is very sensitive to the data period chosen and to the dataset chosen for a given time period, for such a statistical model.

A high value of relative likelihood does not necessarily mean that a model is useful or relevant. The climate is a highly complex physical system; to model it requires an understanding of physical and chemical processes in the atmosphere and oceans, natural variability and external forcings, i.e. with physically-based models. Work undertaken at the Met Office on the detection of climate change from temperature observations is based on formal detection and attribution methods, using physical climate models and not purely statistical models, as discussed in Chapter 9 of the Contribution of Working Group I to the IPCC’s Fourth Assessment Report, 2007.

The second paragraph gives the relative likelihood of the trending autoregressive model with respect to the driftless model. The relative likelihood is 0.08, if we analyze years 1900–2012 , and it is 0.001, if we analyze years 1850–2012 (using Met Office data). In either case, then, the trending autoregressive model is much less likely than the driftless model to be the better model of the data. Hence, the statistical model that was relied upon in the Answer to the original Question (HL3050) is untenable.

Most of the third paragraph is verbiage. In particular, the cited “physical climate models”, which the Met Office runs on its supercomputer, do indeed provide some evidence for global warming. Physical climate models and statistical models are both known as “models”, but they are different things. It is only the statistical models that are relevant to the Question. The physical climate models, though impressive in many ways, do not provide observational evidence for global warming.

The issue here is the claim that “the temperature rise since about 1880 is statistically significant”, which was made by the Met Office in response to the original Question (HL3050). The basis for that claim has now been effectively acknowledged to be untenable. Possibly there is some other basis for the claim, but that seems extremely implausible: the claim does not seem to have any valid basis.

Plainly, then, the Met Office should now publicly withdraw the claim. That is, the Met Office should admit that the warming shown by the global-temperature record since 1880 (or indeed 1850) might be reasonably attributed to natural random variation. Additionally, the Met Office needs to reassess other claims that it has made about statistically significant climatic changes.

Lastly, it is not only the Met Office that has claimed that the increase in global temperatures is statistically significant: the IPCC has as well. Moreover, the IPCC used the same statistical model as the Met Office, in its most-recent Assessment Report (2007). The Assessment Report discusses the choice of model in Volume I, Appendix 3.A. The Appendix correctly acknowledges that, concerning statistical significance, “the results depend on the statistical model used”.

What justification does the Appendix give for choosing the trending autoregressive model? None. In other words, the model used by the IPCC is just adopted by proclamation. Science is supposed to be based on evidence and logic. The failure of the IPCC to present any evidence or logic to support its choice of model is a serious violation of basic scientific principles — indeed, it means that what the IPCC has done is not science.

To conclude, the primary basis for global-warming alarmism is unfounded. The Met Office has been making false claims about the significance of climatic changes to Parliament—as well as to the government, the media, and others — claims which have seriously affected both policies and opinions. When questioned about those claims in Parliament, the Met Office did everything feasible to avoid telling the truth.


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  • Response
    All right you knuckle-draggin', science-ignoring, global warming denialists! Here's your morning read. If you have a progressive friend on Facebook who watches Jon Stewart all the time, she'll be able to help you with the big words. The Parliamentary Question...

Reader Comments (160)

Congrats to Doug on his tenacity.

The Met's performance over this matter and over, for example, the matter of David Holland's FOI requests suggests that, when its back's to the wall, it's hardly a paragon of virtue.

May 27, 2013 at 8:23 AM | Unregistered CommenterRichieRich

Bravo. Well done.

May 27, 2013 at 8:34 AM | Registered CommenterMique

The MET , and particular its leaders , is all in on AGW for its brought them the type of funding and political attention that they could otherwise only dream about . Add to that that is also has some 'true believers ' on board , looking like others to 'use ' the fear of AGW to push a political agenda . And you can see how its works, and its a situation that will not change until its leaders have gone becasue it is under their watch its gone this way.

May 27, 2013 at 8:41 AM | Unregistered CommenterKnR

Must Evade Truth the real meaning of the MET office.

May 27, 2013 at 8:45 AM | Unregistered CommenterPeter Whale

At last the excrement hits the turbine. Terrific!

May 27, 2013 at 8:49 AM | Unregistered CommenterMartyn

Indeed Doug and well argued [thank you] but all the time - the supposition - that MMCO2 = runaway warming was pure claptrap, even the idea of mm CO2 was the significant adding any 'warming' was a preposterous hypothesis notwithstanding Arhenius and his two dimensional lab results.

So it has proved, or not proven as it were.

This is a remarkable week, the Max Planck institute has come up with some pretty similar statements, this is remarkable because it marks the climb down of the Met Off and the German link/PIK - two organisations central and complicit to the global warming carcrash.

Max Planck said:

“These prognoses confirm that the climate models correctly forecast global warming trend over multiple decades, that is until the middle or the end of the 21st century.”

Doh, when is the twelfth of never?

Scientific CLIMB DOWN

NOW we ask - why is the British Government still pursuing the economically illiterate green agenda policies which will cause our industrial and manufacturing to offshore - and thus pushing the country into financial meltdown - policies which no other westernized democracy still believes in - or pursues?


May 27, 2013 at 8:53 AM | Unregistered CommenterAthelstan.

Very well done Doug.

May 27, 2013 at 8:56 AM | Unregistered Commenternot banned yet

Question for Doug... do you now intend to meet Doug McNeall at the Met Office to discuss the implications of this answer?

May 27, 2013 at 9:07 AM | Unregistered CommenterJohn Brady

Doug Keenan is a very formidable opponent.
At the great debate chaired by Monbiot on 14th July 2010 Doug. Fred Pearce and Steve McIntyre totally destroyed the reputation of the UEA, sending Prof Trevor Davies (Phil Jones' boss) home with his tail between his legs.
Doug is reminiscent of the sheriff in 'Butch Cassidy & the Sundance Kid' - he'll never give up until he's got his man.

May 27, 2013 at 9:07 AM | Unregistered Commentertoad

It would be good to see Julia Slingo and Doug McNeall summoned together before the DECC select committee once Peter Lilley is in the loop.

May 27, 2013 at 9:11 AM | Unregistered CommenterJohn Page

You've got to admire Doug Keenan's persistence and tenacity in pursuing this. Lord Donoughue deserves a gong as well.

May 27, 2013 at 9:12 AM | Unregistered CommenterCapell

er...why are my ears bleeding. I think it's because there has been an explosion of such massive proportions that my ear drums are perforated. This is surely the moment people, when 'AGW' was detonated. I can almost here questions being asked in the house such as ' if AGW is a fiction why are we spending billions of pounds trying to stop some fantasy or why are we allowing 20,000 extra deaths a year because of fuel poverty ?

May 27, 2013 at 9:14 AM | Unregistered Commenterconfused

Great chasing Doug. Now you have your teeth in the arses (figuratively of course) don't let go.

May 27, 2013 at 9:14 AM | Unregistered CommenterStephen Richards

Excellent news

What is the chance of main stream media picking this up

Perhaps we should all email this to our mp's

Incidentally some people have been arguing for some years the apparent temperature rise was not real, being due to

1 urban heat effect
2 resiting of weather stations
3 adjustments to the data

here are a few

Ross McKitrick noted there was a jump of about 1C around 1990 when a large number of weather stations stopped being used.

Ross' graphs makes it very difficult if not impossible to interpret as other than the temperature records are not correctly recording world temperature what ever that is

If temperature change (whatever that has been) is due to natural variation, then it isn't due to risiing CO2 levels. This means "climate sensitivity" is not something which exists in the real world.

And if climate sensitivty doesnt exist in the real world any predicitions of future temperature (or past ones for that matter) will just be rubbish.

May 27, 2013 at 9:20 AM | Unregistered CommenterJeremy Shiers

Isn't this the most significant turn of events in the whole sorry mess that is AGW ? or am i being a drama queen. ?

May 27, 2013 at 9:24 AM | Unregistered CommenterStephen Richards

On further reflection:

The headline of this thread is wrong. the MET Office has not admitted

"claims of significant temperature rise untenable ".

What the MET Office has said is:

"The statistical comparison of the model fits shows the likelihood of a linear trend model with first-order autoregressive noise in representing the evolution of global annual average surface temperature anomalies since 1900, ranges from 0.08 (Met Office data) to 0.32 (NOAA data), relative to the fit for a driftless third-order autoregressive integrated model. The likelihood is 0.001 if the start date is extended back for example to 1850 (Met Office data). These findings demonstrate that this parameter is very sensitive to the data period chosen and to the dataset chosen for a given time period, for such a statistical model."

We might all see that this means that the thread headline is correct, but the MET Office will not give up that easily. Would that Josh's cartoon were true, but it hasn't happened; Slingo has not apologised, and I doubt she ever will. I suspect that the MET Office will sit on its hands, confident that the majority of Lords and MPs haven't got a clue about the significance of this answer.

May 27, 2013 at 9:24 AM | Unregistered CommenterCapell

I would like to extend my congradulations to Doug. It is like squeezing blood from a stone. To have to ask a Parliamentary question 6 times before one receives even a partial answer makes the stonewalling appear to me as an abuse of process.

We really need to know what advice the Met Office has been supplying to the Government in the run up to the passing of the Climate Change Act, and of course during the course of this century that has left government and local government so badly prepared for the harsh winters that the UK has experienced since 2009.

One of my bug bears is the globalisation of all of this. There is no such thing as global warming. Some regions are warming, some are cooling and some show no real change.

As far as the UK is concerned, since 2000, the UK has been cooling. CET shows about 0.5degC drop this century. Perhaps of much more significance, CET shows a drop of about 1.5degC in winter temperatures.

Does the government know this? If not why not? If it does know that the UK is cooling (and cooling at a large rate during the winter months), how is it preparing to meet the challenges that that trend will cause should that trend continue.

Has the Government asked the Met Office to comment on that trend and to analyse the statistical likelihood that that trend will continue. If not, why not? If so, what has the Met Office advised?

Whether global warming is a problem and whether the UK should play a role in addressing any perceived global problem is one matter, but quite a different matter is how the UK climate is behaving. The Government certainly needs to be aware of how the UK climate is behaving and to put in place measures that will deal with how the UK climate is behaving.

The present energy policies are madness, but particularly so giving the present trend for cooler winters in the UK, and the increased likelihood that in winter there may well be blocking highs sitting over the UK/Northern Europe that will bring calm conditions rendering windfarms particualry ineffective.

Proper questions need to be asked. .

May 27, 2013 at 9:37 AM | Unregistered Commenterrichard verney

Athelstan at 8:53 AM asks "WHY?"

I venture to suggest:

'The longterm support by leading research scientists, basing their claims and beliefs on scientific evidence, for the discredited Eugenics movement from the 19th well into the 20th century (until WW2) is a classic case of the interdependence of science and cultural beliefs'

In the case of CAGW / AGW / Anthropogenic Climate Change (ACC), the Progressive toxic Greenist MSM have forced a cultural compliance based upon the notion of 'save the planet', a notion that no politician or institution may be seen to disagree with (thanks largely to a pervasive and inviolate foundation of politically correctness among the chattering intelligentsia), and QED much of science also 'supports' for reasons largely related to self-interest.

Only, it's gradually becoming less about science now, more about the wallet and thence political survival.

May 27, 2013 at 9:37 AM | Unregistered CommenterManfred

I'm struggling a bit with the plain language interpretation the response to the final parliamentary question.

Is the implication that warming has occurred since 1850, but not outside the amount that might be expected by natural variation. However the warming since 1900 is outside the amount that might be expected by natural variation?

If that is right, what have the Met Office actually admitted? Merely that warming started after 1850.

May 27, 2013 at 9:39 AM | Unregistered CommenterAndyL

Further to the comment made by Jeremy Shiers (May 27, 2013 at 9:20 AM ), the satellite data shows no, or all but no, warming between 1979 and 1996/7 and this therefore suggests that the warming between 1979 to say 1997 seen in the land based thermometer record may be nothing more than an artefact of polluted data in that record, such as a bias brought about by station drop out, poor station siting, UHI and the like.

May 27, 2013 at 9:55 AM | Unregistered Commenterrichard verney

Sorry for being a dumb arse but does this mean the likelihood warming is Mann made is .0001?



May 27, 2013 at 10:06 AM | Unregistered CommenterMailman

Congratulations to Doug on dragging this out from them. The acknowledgement that what warming has taken place is not yet significant is a very important one, particularly that it's more true over the longer timescale.

The part of the article that angers me most however, is “Ministers who knowingly mislead Parliament will be expected to offer their resignation to the Prime Minister”. I assume that this wording is used so that the Minister involved can step aside gracefully and not lose contractual benefits. If anyone who worked for me mislead me knowingly it would be gross misconduct and out the door sharpish with statutory rights only.

May 27, 2013 at 10:11 AM | Unregistered CommenterCumbrian Lad

Mailman - whether man has contributed to the warming seen since 1850 or rather since 1950 is still an open question. The question that Doug Keenan and Lord Donoughue are asking is whether the temperature rise is significant so that a human signal can be detected amongst the noise. The answer to that question currently is no.

May 27, 2013 at 10:21 AM | Unregistered CommenterLiT

This is a great story but, IMO, presented too lengthily and technically to get widespread public attention.

If it could be compressed to,say, 4 paras, with the essential points easily graspable by educated laypeople it would be very he;pful

May 27, 2013 at 10:35 AM | Unregistered CommenterLatimer Alder

AndyL states (May 27, 2013 at 9:39 AM):
"I'm struggling a bit with the plain language interpretation the response to the final parliamentary question."

I consider that a further question should be posed which explicidly requests either a YES, or NO answer as is frequently asked in a Court of Law. Obviously, the wording of the follow up question needs to be carefully considered, but something along the following lines

Further to question HL62 and the answer given on [insert date], if the statistical comparison of the model fits shows the likelihood of a linear trend model with first-order autoregressive noise in representing the evolution of global annual average surface temperature anomalies since 1850 using Met Office data relative to the fit for a driftless third-order autoregressive integrated model, of 0.001, is such result statistically significant? When answering this question, please confine the answer to a simple answer YES, or NO (as the case may be).

May 27, 2013 at 10:42 AM | Unregistered Commenterrichard verney

Of course Global Warming must be happening.

Only last week our Government, at great expense, published "The Heatwave Plan for England 2013"

May 27, 2013 at 10:51 AM | Unregistered CommenterJoe Public

The 0.001 refers to the likelihood ratio between two rival statistical models.

One is a linear trend model with first-order autoregressive noise, the other is a driftless third-order autoregressive integrated model.

The first model (which the Met Office had been using) is a thousand times less likely than the 2nd model (1/1000 = 0.001). Therefore the most appropriate model to use in looking for trends is the 2nd model.

Using the 1st model there appears to be statistically significant warming 1850 - 2012. But this model is less appropriate than the 2nd.

Using the 2nd model there has been no statistically significant change in global temperature over that time.

Clearly there has been an increase in global temperature, but this cannot so far be explained, other than by random variability. If CO2 is playing a role it is still within this random variation. Of course this could change...

May 27, 2013 at 10:51 AM | Registered CommenterQ

I suspect a few commentators haven't quite twigged on as to "Mann made"!
(No spelling mistake)

May 27, 2013 at 11:02 AM | Unregistered CommenterAdam Gallon

woe, woe and double thrice woe

May 27, 2013 at 11:04 AM | Unregistered CommenterAnoneumouse

Maybe it is time for Lord D to play the game the Met Office way.
He could thank them for the eventual response and go on to say that it is very good news because, in layman's terms, it means that the recent warming is NOT significant. It falls within the bounds of natural variability.
His follow-up question should be to ask the Government how it intends to change its policies in light of this revised advice from the MO?
That would be fun. If only.....

May 27, 2013 at 11:09 AM | Unregistered CommenterMikeH

Well done, Doug. I have as much statistical knowledge as the average house brick, but, on the other hand, decades of experience observing human beings. From Doug's clear-minded persistence, and from his opponents' evasiveness, inductive logic tells me that he has the truth on his side.

May 27, 2013 at 11:15 AM | Unregistered CommenterAlex Cull

Er, does that mean there's no scientific basis for AGW, because it sounds like it.

May 27, 2013 at 11:20 AM | Unregistered CommenterSwiss Bob

The highest probability answer is that the Met Office is packed with autoregressives.
Incapable of reasoned thought.

May 27, 2013 at 11:25 AM | Unregistered CommenterDon Keiller

I am with Latimer Alder on this one. The "significance" of this story is not immediately apparent to anyone but a statistician. I grasp its importance but I do not pretend to understand the maths. Can someone send it to Mr.Rose at the Daily Mail who could perhaps knock it into a story with the right help? It will be important it get it exactly right because the backlash "debunking" efforts would be fierce.

May 27, 2013 at 11:29 AM | Unregistered CommenterJack Savage

Another question which needs to be asked is why were they using a linear model when "the data" shows clear signs of cycles (around 60 years) and spikes/pulses (eg 1998 el nino and 1991 mount pinatubo eruption).

They might as well as have added, we're going to do something that's wrong, we know it's wrong (well maybe not to that one) but it gives us the result we want.

After all if you try and fit a linear curve to a wave you can get pretty much any result you like simply by choosing your start and end points.

And speaking of waves reminds me of sea levels. It is commonly reported this Climate Change movement has lead to a government policy which is producing large increase in energy prices.

There are other branches of government (DEFRA/EA/NE) who are using the climate change story to justify knocking down sea walls all around the UK. THis is of particular concern to me as I live in Essex about 1/2 mile from sea wall, which EA wanted to knock down. (Essex is particularly low lying so disproporationately affected by this policy).

The argument seems to be

Temperatures are rising
This will cause sea levels to rise by up to a metre
This means it will be uneconomic to maintain sea defenses
So the best thing is to knock them down now.

more here

Natural England get in on the act by claiming rising sea levels are causing coastal squeeze (an entirely fictious ailment) which is killing saltmarsh and the EU Habitats Directive require new saltmarsh to be created. One of the key features of salt marsh is that rises with rising sea level appears to be completely ignored by NE and EA (why let the facts spoil a good story).

There are other reasons why salt marsh is being eroded such as crabs and salt marsh

In the video EA make the claim that there role is only to respond to man made sources of rising sea levels. A woman from Suffolk council says it could be crabs or all sorts of other things. An FOI revealed Suffolk council held no information to justify this claim.

Why have I gone on this protracted ramble?

Firstly to publicise a policy being implimented in the name of climage change

Secondly to try and show ignorance and obsfucation are everywhere

In AR4 it is stated thermal expandsion of water is due to half sea level rise
so if temperatures aren't rising there ain't going to be so much of that

The other 1/2 is due to melting ice and if temperatures arent going to rise so much there won't so much of that neither.

Incidentally the claim in AR4 that sea levels are now rising at 3mm/year up from about 1 is false.
What seems to have happened is sea levels were depressed following mount pinatubu and raised by 1998 el nino. This lead to a temporary increase which was since levelled off.

There was some interest in this last year when the satellite records of Envisat were bodged to bring them into line with the required rate of sea level rise

People making misleading statements and altering data who'd have thunk it.
The only think is, to misquote Peter Cook, these are people who can't even manage a simple case of massaging data without cocking the whole thing up.

Once again climate change has been used to set current government policy which involves literally destroying parts of UK by flooding.

May 27, 2013 at 11:30 AM | Unregistered CommenterJeremy Shiers

Jeremy Shiers: In stead of statistical models I would rather trust the well known decline effect. Why does the estimated climate sensitivity decline with each new study? Perhaps because the true value is zero and the present estimate (including confidence interval) cherry-picked? BTW, McKitrick did not show in his graph that since 1990 the station population almost completely changed and that the small remaining number was cherry-picked on the basis of correlations between time series from adjacent stations.

May 27, 2013 at 11:35 AM | Unregistered CommenterMindert Eiting

What about our host to interpret the Doug Keenan post for the layman?-He's done such work successfully before, in HSI for example. Hey, Bishop, have you got the time for this?

May 27, 2013 at 11:43 AM | Unregistered CommenterMessenger

Of course Global Warming must be happening.

Only last week our Government, at great expense, published "The Heatwave Plan for England 2013"
May 27, 2013 at 10:51 AM | Joe Public



Mindert Eiting,


Jeremy Shiers: In stead of statistical models I would rather trust the well known decline effect. Why does the estimated climate sensitivity decline with each new study? Perhaps because the true value is zero and the present estimate (including confidence interval) cherry-picked? BTW, McKitrick did not show in his graph that since 1990 the station population almost completely changed and that the small remaining number was cherry-picked on the basis of correlations between time series from adjacent stations.

An astute and at the same moment - an scathing observation and very well 'said'.

May 27, 2013 at 11:48 AM | Unregistered CommenterAthelstan.

@Mindert Eiting

Climate sensitivy relates temperatures to co2 levels and (for sake of argument) is the number of degrees temperatures rise for a doubling of CO2 levels.

There is an assumption here which is doubling CO2 levels actually cause temperatures to go up.


that you can project/predicit future temperatures based on future projects of CO2

Of couse if CO2 does not cause rising temperatures then any projections of future temperatures will be meaningless, though it doesnt stop you or anyone else making them

What seems to have happened is for a short period of time CO2 levels and temperatures went up together - they were correlated if you want to be posh.

This lead to certain value of climate sensitivity (say 5C)
But then temperatures stopped going up whilst CO2 levels continue to rise

As time went by this lead to values for climate sensitivty (4,3,2,1)

Perhaps temperatures drop far enough climate sensitivity may appear to be negative

Just the fact climate sensitivity appears to change over time without rhyme or reason tends to suggestion its efficaciousness for future temperature predictions are somewhat diminished.

Incidentally this blog carried a link to this video
of Nir Shaviv at EIKE

around 23min he shows how climate models require a large value of climate sensitivity to explain temperature rise over 20century (which may not have happened due to dodgey temperature data).

And this large value of climate sensitivity causes the models to produce large temperature changes after volcanoe eruptions. This large temperature changes did not actually occur.

If you turn the problem around and adjust the value of climate sensitivity so the models actually fit the observed data (radical idea that) you get a much lower value of climate sensitivity - around 1

Does this mean that the value of climate sensitivity is 1


For 2 reasons

Firstly it assumes that CO2 actually does cause temperatures to change whereas there are now multiple reports that CO2 levels change because of changes in temperature

Murray Salby has given 2 lectures at Sydney each with a different reason why CO2 does not cause temperature change. Bizarrely these videos where put on youtube as private so I put a link and wrote up one of the lectures here

I strongly recommend watching both videos

alternatively try this in the comfort of your own browser

Secondly the models do not include the effect of changes in sun's output, changes in cloud cover so even if CO2 was causing temperatures to change the models would overstate the amount by which CO2 caused temperatures to change and hence overestimate the value of climate sensitivity.

Thirdly the models include an assumption that increased temperatures will lead to more water in the atmosphere, H20 is the dominiant green house gas. And the predictions of future warming depend on increased amounts of water vapour, CO2's role is only to cause this increase in other words no one ever said rising CO2 levels would raise temperature's directly.

BUT as far as I know there is no suggested mechanism as to how this increase in water vapour works, just an assumption built into the models that it does (See Peter Taylor's book chill)

You could say it was vapourware

May 27, 2013 at 12:07 PM | Unregistered CommenterJeremy Shiers

"The physical climate models, though impressive in many ways, do not provide observational evidence for global warming."

Key sentence.

May 27, 2013 at 12:13 PM | Registered Commentershub

Whatever the cause of any mild rise in the global average temperature - and consider that no one lives or can be located where that average may be experienced (for that time and at that time) - the question to be asked is whether any so-called man-made warming has made those parts of the world where people do live any less hospitable given their accumulated human and non-human capital?

May 27, 2013 at 12:18 PM | Unregistered CommenterBob Layson

Is it statistically significant that the question had to be asked 6 times?

May 27, 2013 at 12:28 PM | Unregistered CommenternTropywins

Apocalyse Now sorry the Apocalyse is cancelled

May 27, 2013 at 12:39 PM | Unregistered Commenterjamspid

I must admit that even with my undergraduate statistics I found this convincing analysis devastating - how did the Met office not do so? Is this the game changer? I hope so.

May 27, 2013 at 12:39 PM | Unregistered CommenterTrefjon

The MSM would never grasp it, the Significance. They'd just see it as some obscure statistical argument and defer to the authority of the tax payer funded institution, the Met office.

The question of misleading Parliament though, that story may have some way to run.

May 27, 2013 at 12:47 PM | Unregistered CommenterRenee Deschamp

Shub - "though impressive in many ways,"

Hmm, I wonder what they have in mind?? AFAIK they do not withstand critical evaluation:

A Literature Debate On The Lack Of Skill Of Global Climate Model Multi-Decadal Predictions As Reported In The Peer Reviewed Literature By Demetris Koutsoyiannis

May 27, 2013 at 12:50 PM | Unregistered Commenternot banned yet

If the proposed meeting between members of the Global Warming Policy Foundation and Fellows of the Royal Society takes place then difficulty of getting a straight answer from the Met Office to a straight forward question about what statistical model(s) it used could be discussed under item 2 of the proposed agenda.


1. The science of global warming, with special reference to (a) the climate sensitivity to carbon dioxide and (b) the extent of natural variability;

2. The conduct and professional standards of those involved in the relevant scientific inquiry and official advisory process

May 27, 2013 at 12:51 PM | Unregistered CommenterRoy


The truth is very much stranger than that when we examine CET-the worlds oldest instrumental record and which is said by many scientists to be a reasonable but by no means perfect proxy for Global temperatures

Here are the latest Met office figures to 1772 showing a 0.4C anomaly

Here is the Met office extended data to 1659-it is my own reconstruction from then to 1538

Temperatures currently after the recent decade long dip are about 0.2 higher than the 1830’s and indistinguishable to the 1730-‘s and currently lower than my reconstructed figure for 1500-1540 approx.

The 1880’s were of course a noted period of temperature decline and I have always wondered why Giss decided to measure from that point


May 27, 2013 at 12:56 PM | Unregistered Commentertonyb

Would now be a good time to formally ask the Royal Statistical Society for its comments?

The RSS has been very sensible so far, in avoiding any input into this politically dangerous topic. But there is a groundswell of changing opinion now - I wonder if they can be persuaded to nail their trousers to the mast?

May 27, 2013 at 1:04 PM | Unregistered CommenterDodgy Geezer

"One is a linear trend model with first-order autoregressive noise, the other is a driftless third-order autoregressive integrated model."

Fine. So can anyone translate what that means for each model? Perhaps give an everyday example of each, or an analogy or whatever?

May 27, 2013 at 1:10 PM | Unregistered CommenterMichael Larkin

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