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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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    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 (163)

Dodgy Geezer - no need IMO. Doug has done the job.

Perhaps a request/FOI to the Met Office for the full details of the calculations used to answer Lord Donoughue's questions would be worthwhile for the public record (maybe it is in the footnotes Doug refers to?). I also think an FOI to the Met Office for their internal correspondence on this matter would be interesting.

May 27, 2013 at 1:16 PM | Unregistered Commenternot banned yet

Assuming that Hirst et al. will simply ignore this revelation, extrapolating baseless linear trends ad infinitum, to what extent will such as the ignorant and terminally obnoxious Mde. Slingo be rewarded for slathering the Met Office's response with fatuous gunk for six months now? Calling Slingo a "scientist" is like calling J.B. Rhine a "researcher."

May 27, 2013 at 1:24 PM | Unregistered CommenterJohn Blake

Surely Slingo must be called before Parliament to account for the Met Office refusal to answer questions from a member of the House of Lords. She has so much form for a variety of offences her continued presence at the Met Office is an embarrassment.

May 27, 2013 at 1:42 PM | Unregistered CommenterJohnB

Doug Keenan, so how would you answer for your 10 coin flip example? Is that event statistically significant or not? To focus more on the underlying idea I'm curious about, is it correct to pick a model that most closely fits the data (a one-sided coin) and lowers statistical significance, or a model that better reflects reality (there are a lot more two-sided coins than one-sided)?

May 27, 2013 at 1:46 PM | Unregistered Commentermt

I wonder if Dr Betts has any comments on this post and, of course, its conclusions?

May 27, 2013 at 1:47 PM | Unregistered CommenterDave Salt

@Michael Larkin

The model with the "linear trend" assumes that the process is a combination of unexplainable ups and downs (random variation) that is partly dependent on what happened in the period immediately prior. So it says the temperature is rising with a long term straight line trend, but buffetted around by random variation. Think a straight line pointing up, with random variation making the data rise above or fall below over shorter periods.

The "driftless" model assumes the process is only due to a series of unexplainable ups and downs (random variation) that is dependent on what happened over the last 3 periods. It assumes there is no long term trend. Any observed upward or downard drift is just chance.

Think of it this way. Imagine to two people using a die to generate a random walk down the street. Don't worry about the rule they use, simply picture them making steps forward, backward or not depending on the outcome of the roll of the die. Now imagine that one of those people also makes one deliberate step forward before each roll of the die that determines the random step.

Well, the person who takes the deliberate step at each stage in addition to rolling the die is the "linear trend" model (don't worry about the autoregressive bit).

The person who takes no deliberate step, but only steps according to the outcome of the roll of the die, is the "driftless" model.

May 27, 2013 at 1:50 PM | Unregistered CommenterGeckko

Is it fair to summarise the situation regarding climate science as follows:
- Warmist claims can use any old statistical/climate model as justification
- Precise claims by sceptics are to be ignored at all costs..?

May 27, 2013 at 1:51 PM | Unregistered Commentersherlock1


As explained, the "singificance" only applies in relation to an assumed model.

So 10 straight heads would be "statistically significant" for the "fair coin model", but not "statistically significant" for the "two head coin model".

Thus is in the choice. We can chose which of two assumed models would be more likely to be the correct one, given the data we observed.

If you witnessed a street gambler produce 10 straight heads when tossing a coin, would you place a bet that:

You just witnessed a chance event from a fair coin toss, or

You just witnessed an event that did not result from a fair coin toss (i.e. something else was inlfuencing).

You would bet on the latter and intuitiviely would have calculated the statistical significance of the event under those two different models.

May 27, 2013 at 2:00 PM | Unregistered CommenterGeckko

If I'm watching a street gambler, I'm not betting on anything, because when the coin was verified, it would always be the opposite of what I bet on.

May 27, 2013 at 2:53 PM | Unregistered Commentermt


I downloaded the Met Office data and charted it. I get a decline in the mean temperature from the late eighties!

Here in Switzerland they admit that the first quarter of this year was a lot colder than normal:

North of the Alps and the Alps, medium and high altitude, winter 2012/2013 turned colder 1 to 2.5 ° relative to the standard from 1981 to 2010. North of the Alps, precipitation amounts were surpluses, they were largely deficient in the south. In the more northern regions in winter was particularly little sunshine.

This morning it was a chilly 5 ° at 9.00 am.

May 27, 2013 at 2:58 PM | Unregistered CommenterSwiss Bob


That is my point. I didn't say you would bet on the outcome, I meant what would you sumise your were observing - which is a probabiilstic statement, or "bet".

The fact that you wouldn't actually bet means you "bet", or sumise, that you aren't witnessing a fair toss. Get it?

May 27, 2013 at 3:00 PM | Unregistered CommenterGeckko

"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."

This phrasing is LOL funny! It reminds this Monty Python fan of an old gem:

"When I first came here, this was all swamp. Everyone said I was daft to build a castle on a swamp, but I built in all the same, just to show them. It sank into the swamp. So I built a second one. That sank into the swamp. So I built a third. That burned down, fell over, then sank into the swamp. But the fourth one stayed up. And that's what you're going to get, Lad, the strongest castle in all of England."

May 27, 2013 at 3:01 PM | Unregistered Commenterchris y

Superb. Well done Doug. And Lord D.

May 27, 2013 at 3:04 PM | Unregistered CommenterJimmy Haigh.


Climate skeptics everywhere give a nod to Doug.

May 27, 2013 at 3:11 PM | Unregistered CommenterAnthony Watts

One reason I ignored the GW story until I saw Al Gore’s film (which scared me – as was its intention – though, in my case, I tried to educate myself about it, not just believe what a possibly biased few told me) was that I wondered what the fuss was about: if it is only within the last 50 years that thermometers have become accurate to within 0.5°C, then that implies that a hundred years ago larger errors would have been acceptable. This means that, if the average thermometer error in 1880 was 0.6°C LOW (i.e. within acceptable margins), and the more modern thermometers have an average error 0.2°C HIGH (still within acceptable margins), then the real temperature increase is ZERO.

It would be interesting to know the statistical probability of that being the case.

May 27, 2013 at 3:17 PM | Unregistered CommenterRadical Rodent

Well done Doug and Lord Donahue - it is good that you stuck to your guns. As for the Met Office - this 'organisation' should never be linked to any mention of practising actual science - they are a wilful disgrace to other scientists, the government, themselves and the British people. Personally, I would rather the likes of Slingo and Jones, etc, take a running jump - but they don't even have enough of integrity or honour to do that either !
As Gordon Ramsay might say - 'Shut it Down' !

May 27, 2013 at 3:26 PM | Unregistered CommenterKev-in-Uk

Blistering! Well done Doug.

May 27, 2013 at 3:52 PM | Unregistered CommenterPeter F Gill

"Most of the third paragraph is verbiage."

It is easy to cut through that verbiage: That third paragraph is saying, "the science is settled".

I have shown, 2 1/2 years ago now, that the science is NOT settled, but wrong and indeed incompetent. As I have said over and over, climate science will not advance until my definitive evidence is properly confronted, and accepted by all. The finding presented here, that there is no statistically "significant temperature rise", is tacit endorsement of my position, which first and foremost affirms that the Standard Atmosphere model is the stable, UNCHANGING (except to changes in the incident solar power), governing equilibrium state of the troposphere. It is that simple, and it is a revolutionary disproof of consensus climate science. In my Venus/Earth comparison, I found that the Standard Atmosphere for Earth differs from the actual temperature vs pressure profile of Venus (over the range of Earth tropospheric pressures) only due to the difference in solar distance of the two planets (simply put, and for the 1,000 mb pressure level in particular: The Venus temperature at 1000 mb is exactly what the surface temperature of Earth--also at 1000 mb--would be, if Earth were as close to the Sun as Venus--even though Venus has over 2400 times the CO2 level as Earth, 96.5% vs. .04%.) There is NO CO2 "greenhouse effect", of increasing temperature with increasing CO2--and thus there are NO competent climate scientists, who all promulgate that false and incompetent theory.

May 27, 2013 at 4:06 PM | Unregistered CommenterHarry Dale Huffman

I will try to equate the 10 coin flips all being heads to 10 temperature data set adjustments all resulting in more warming.

Model 1: All adjustments are made in a completely objective manner. (Coin is fair)
Model 2: All adjustments are not made in a completely objective manner. (Coin is not fair)

I am not a statistician but I have intuitively found it strange that all temperature adjustments have resulted in later warming, earlier cooling or both.

Or am I off base here?

May 27, 2013 at 4:14 PM | Unregistered CommenterMikeC

Founded in Aug 1861, the Met Office has gotten increasingly worse predictions using the latest super computers but a defective Carbon forcing model. Nature does not conform to human fads and Nature Met barbie summers with cold and damp....Nature Met hose pipe bans with floods....Nature Met warmest winters with record cold. This winter [warmest Met guess] had over 30,000 cold related deaths, statistics that did not require a suer computer to understand. Therefore on 09 April 2013 the Met announced that they would no longer provide 'public' long range forecasts but would still provide that 'service' to the government....who pays Met expenses....and doesn't mind exchanging tax money for dripple. Unhappy with the Met announcement, i posted the following revised version:

The Met Office has admitted that predictions about weather and climate are beyond the ability of charlatans with super computers, and have therefore switched to the seance with poltergeist form of forecast. Future Met predictions will be made by the ghost of the late Marcel Marceau...."the mime who brought poetry to silence"....offering the public the same level of accuracy and entertainment as our recent forecasts."

Perhaps if the masters of the Met had not invested 30% of the pension fund in Carbon futures, they could employ a climate model that was not Carbon forced.

May 27, 2013 at 4:26 PM | Unregistered CommenterFaux Science Slayer

guest post by Doug Keenan. May 27, 2013

(...) 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.(...)

I don't get it. Do the Met Office's physical climate models provide evidence (observational or otherwise) for global warming, or do they not?

To me an unvalidated model is, as someone said, an illustration of a hypothesis - it does not provide evidence.

The Met Office claims that their models provide evidence for human-caused global warming. Some time ago, Richard Betts of the Met Office gave a reference here on BH to a Met Office paper said to confirm the effects of fossil-fuel CO2.

Running the models with CO2 effects switched off did not reproduce the warming seen from 1960 to 1998 or thereabouts. But, with CO2 effects turned on, the historical data (up to ~1998) was reproduced faithfully. So far as the Met Office is concerned, there is your proof.

This was faithfully reproduced by IPCC:

Figure 9.5. Comparison between global mean surface temperature anomalies (°C) from observations (black) and AOGCM simulations forced with (a) both anthropogenic and natural forcings and (b) natural forcings only.

And is reproduced on the Met Office's MyClimateAndMe web site:

When climate scientists consider all the ‘natural factors’ that could be affecting our climate, the long-term temperature trend (green line) in the chart below is broadly flat. Introduce the effect of man-made greenhouse gases into the mix and the computer model produces a line that tracks almost directly onto the observed temperature rise.

If the evidence for AGW is nothing more than the output of unvalidated computer models, then the evidence is in the range "weak to nonexistent" so far as I can see.

May 27, 2013 at 4:26 PM | Registered CommenterMartin A

This has to be simplified in its presentation. Only motivated readers (i.e. skeptics) will even attempt to wade through it. If you don't make this information easily understood....or at least more easily will have little practical effect imo.

May 27, 2013 at 4:26 PM | Unregistered Commenterpokerguy

@Geckko Because you inserted "street gambler", I would throw out any prior knowledge about coins and flips, and assume I was going being tricked. If we took a random person walking on the street, who pulled a coin out of his/her pocket and flipped 10 heads, what's more likely, a rare string of flips or an even rarer one-sided coin? Just because a model better matches observations, it doesn't mean that model is more likely if we know other information about the models.

But I'm not really interested in coin flips, and I'm wondering if there isn't something a bit more subtle here. It seems that, for this temperature series analysis, another way to say "statistically significant" is "unexpected". Doug's ARIMA model is a description of how we expect the "climate" to behave. The observations fall within the model's expectations, but that really doesn't tell us anything about the cause of the warning, or whether the observations match what we'd see if we were still waiting for the Industrial Revolution to start.

May 27, 2013 at 4:26 PM | Unregistered Commentermt

@doug keenan

Would you or Lord Donoughue ask Met Office why they choose to fit a straight line to a series which has fairly regular cycles (or more accurately shows a combination of different cycles of different periods)?

As to the cause of these cycles perhaps we could look to changes in sun's behaviour (known to be cyclical) as well as the orbits of moon and other planets?

May 27, 2013 at 4:37 PM | Unregistered CommenterJeremy Shiers

Ah, wriggle, squirm, obfuscate...

This is known as a Clown Dance.

May 27, 2013 at 4:58 PM | Unregistered CommenterCatweazle

They aren't going to turn round and say "Oops, this is all wrong and we'll sell the super computer"
"Met Office climate research has always played a key role in informing this (IPCC) process and the next report, the Fifth Assessment Report (AR5), due out in late 2013 will be no different with several Met Office scientists playing major roles as lead authors and coordinating lead authors for the report.

One crucial aspect of the assessment report is in making projections of future change which draw on state-of-the-art climate models.

About 10,000 model years have been simulated and more than 165,000 data files have been processed and sent to the "Earth System Grid" - the distributed database that will make the CMIP5 results from all modelling centres available for researchers around the world to analyse.

All of the hard work developing and running our models would count for nothing if we were unable to deliver our data in a timely manner in the required format to the end users. This in itself has been a huge undertaking, and has required world-leading IT support and infrastructure every bit as much as the modelling has required world-leading science expertise.

To date we have delivered 45 TB of data - or around 90 times the amount of data we sent for the equivalent exercise for the last IPCC report (AR4), with up to 5 TB still to come over the next few months."

May 27, 2013 at 5:19 PM | Unregistered CommenterDennisA

Two quotes from the post:

"The issue here is the claim that “the temperature rise since about 1880 is statistically significant...The basis for that claim has now been effectively acknowledged to be untenable."

"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"

I am not quite able to connect these two statements.

If the apparent rise in temperatures is not statistical significant, it means that it could be an artifact of statistics used, measurement inaccuracy, etc. Non-climate variations. It can not be asserted that the rise represent an actual rise out here in the real world.

Why then should the met Office admit that the apparent rise could be attributed to "natural random variation"? If it is not statistically significant, we don't even know if there has been an actual rise out here in the real world, right? So the exercise of attributing it to anything is pointless.

Besides, I don't like the term "natural random variation". The climate system is chaotic, but it is not "random". There are clear trends on both shorter and longer time scales and we know a lot of the factors involved and quite a bit about how they influence each other.

The term is confusing also because "random" implies that there can not be any longer term trends from natural causes. In random noise there are no long term trends. The implication is that any longer trend must be caused by other than natural factors, such as emissions of CO2.

May 27, 2013 at 5:21 PM | Unregistered CommenterBathes

Pulling teeth to get an answer...well done!

However, I really do not like motivating example. I think most everyone, and certainly the man on the street, will have a strong prior that a coin is a fair coin. Getting 10 heads in a row would not be sufficient to completely abandon the fair coin assumption given such a strong prior.

To get around the strong prior issue, perhaps the example could start with "one fair coin and one two headed coin are placed in a bag...I select a coin at random and flip it 10 times...I get 10 heads...which coin am I more likely to have selected?" It is clear here that the data helps me select the appropriate model (or coin)

With this setup, I have an equal prior for each coin type, and I think that gets around my concern.


May 27, 2013 at 5:38 PM | Unregistered CommenterJames


Thanks for once again drawing my attention to your CET graph. I notice that you use the same type of graph as the MET do for this data - you draw a vertical blue line from the 0° anomaly line to the data point. This gives the curious impression that something very strange happened in about 1990 - suddenly there is a lot of solid blue on the graph. Would a point-to-point graph be feasible? I think it might display the data more clearly.]

May 27, 2013 at 5:38 PM | Unregistered CommenterJames Evans

"To date we have delivered 45 TB of data - or around 90 times the amount of data we sent for the equivalent exercise for the last IPCC report (AR4), with up to 5 TB still to come over the next few months."

How many hours of streamed HD soap opera does that equate to?

May 27, 2013 at 5:40 PM | Unregistered Commenternot banned yet

Doug - You have been very persistent and successful in pursuing statistical approach and the Met Office has done everything to obfuscate the situation. I personally think that the entire global warming movement lacks any legitimate scientific justification, something that has nothing to do with statistics. First and foremost, there is that "greenhouse effect" from carbon dioxide that they claim is warming up the world. There is good physics to prove that it does not even exist but I will stay with straight physical properties of carbon dioxide.

The claim is made that carbon dioxide is a greenhouse gas that absorbs outgoing long-wave radiation. Absorbed radiation then turns to heat, warms the air, and we have the atmosphere getting warm. Another claim is that increasing the amount of carbon dioxide in air will increase the amount of warming. Let's see if this is true. Atmospheric carbon dioxide is measured directly by the Mauna Loa observatory in Hawaii and indirectly by ice core data. Going back to the beginning of the twentieth century we notice that its first ten years were cooling, apparently a downswing from a climate oscillation that preceded it. Then , suddenly in 1910, warming started. We know that there was carbon dioxide in the air then, but it cannot start a warming by simply being there. If that warming was a greenhouse warming the only way to start it is to add a large amount of carbon dioxide to air at the same time. That is because the IR absorbance of carbon dioxide is a property of the gas and cannot be changed. The only way to increase IR absorption is to increase the amount of the absorbing gas. Fortunately we have good records of atmospheric carbon dioxide and these records show that there was no increase of CO2 content of air in 1910. It follows immediately that this warming cannot possibly be classified as greenhouse warming. The warming lasted thirty years and then stopped in 1940 as suddenly as it had started. It so happens that you cannot stop greenhouse warming suddenly because there is no way to suddenly remove carbon dioxide molecules from air with which they are mixed. The sudden stop of this early century warming tells us the same thing its sudden start did, namely that it cannot be greenhouse warming. By now the first forty percent of the century is proven greenhouse warming free by simply basic physics.

What about the rest of the century? There was no warming after that until mid-seventies. Warming advocates are well aware of this and have suggested various excuses, one of them being aerosols from war production cooling the air. But about 1976 a new warming started that was dubbed the "Great Pacific Climate Shift" at the time. It was later associated with a change of PDO (Pacific Decadal Oscillation) from its cool to warm phase. Apparently it raised global temperature by around 0.2 degrees Celsius and was over by 1979 or 1980. Again, there was no change in atmospheric carbon dioxide at the beginning of it which rules out the greenhouse effect for its duration. We have now covered eighty percent of the century and can certify it greenhouse free by the laws of physics. What follows is the satellite era which began in 1979. Looking at satellite temperature record we find that there was no warming at all from 1979 to 1997. None, and yet global carbon dioxide was steadily increasing. But there was fake warming called the "late twentieth century warming" in that time slot. I kept protesting that fake warming and what do you know - last fall GISTEMP, HadCRUT and NCDC in unison decided to get rid of it. Nice cross-pond cooperation. Or conspiracy. They knew just what to do and did not say anything about it. This 18-year no-warming period was followed by the super El Nino of 1998. It brought a very large amount of warm water across the ocean with it. In only four years this raised global temperature by a third of a degree and then stopped. There has not been any warming since then. The step warming of 1998 was the only warming during the entire satellite era starting from 1979 until now. Applying only the laws of elementary physics we have eliminated greenhouse warming from the remainder of the twentieth and all of the twenty-first century. Altogether, we can say that there has been no anthropogenic greenhouse warming since the beginning of the twentieth century. Please inform the good Lord Donoughue of this fact. And pass it on to Julia Slingo, Baroness Verma, and John Hurst as well.
[Paragraphs added for easier reading. BH]

May 27, 2013 at 5:43 PM | Unregistered CommenterArno Arrk

I agree with Richard Verney. I hope Lord Donoughue asks a follow up question along the lines of, "I understand that the answer given to the earlier question about statistical significance of the temperature increase since 1850, which was that yes, it was significant, relied on the trending autoregressive model. Since the driftless ARIMA model is 1000 times more likely than the trending autoregressive model, then using the driftless ARIMA model, is the temperature increase since 1850 significant?"

It would be good to get them on the record that it is not significant using the higher likelihood model.

May 27, 2013 at 6:02 PM | Unregistered CommenterTom Wiita

Martin A:

If the evidence for AGW is nothing more than the output of unvalidated computer models, then the evidence is in the range "weak to nonexistent" so far as I can see.

Still with you on that, fella.

Tom Wiita:

It would be good to get them on the record that it is not significant using the higher likelihood model.

That's the next step. After which we're all in the same dark about what's really going on in that jolly old atmosphere (and oceans) of ours.

May 27, 2013 at 6:26 PM | Registered CommenterRichard Drake

Because of his extraordinary work at pulling teeth in the Met Office and its bureaucratic supporters, Mr. Keenan is a hero of our time. Lord Donoughue merits thanks also. The good news is that individual heroes can accomplish something even today.

Brilliant work in distilling your argument for the purposes of Parliament, Mr. Keenan. Please do not accept the Met Office's invitation to supplement your tooth pulling with gum surgery.

May 27, 2013 at 6:59 PM | Unregistered CommenterTheo Goodwin

Right, so there is no global warming.

Fair enough!

Somebody had better go and tell the glaciers that they can stop receding.

May 27, 2013 at 7:08 PM | Unregistered CommenterBrian C

OT but "related.". Mr. Keenan, I have read many of your posts at BH and elsewhere for several years but hadn't "connected the dots." I have been drinking your (?) wines for years, assuming that you and Robert Keenan are related.

Please give me a shout if you are ever in the San Francisco Bay Area and I will bring along a bottle or two of Robert Keenan's outstanding merlot for immediate consumption. And for those of you who sneer at merlot, I remind you that Chateau Petrus is 100% merlot!

May 27, 2013 at 7:20 PM | Unregistered CommenterRayG

Right, so there is no global warming.

Fair enough!

Somebody had better go and tell the glaciers that they can stop receding.
May 27, 2013 at 7:08 PM Brian C

"there is no global warming."

Did anybody say that?

There is no dispute that, on and off, the Earth has been warming since the Little Ice Age. And, for that matter, since the last real ice age.

Showing that the Met Office's claim of "statistical significance" was unjustified in no way contradicts that.

May 27, 2013 at 7:21 PM | Registered CommenterMartin A

James Evans

I deliberately wanted my own CET graph to follow the format of the Met office. Here it is graphed in a different manner showing decadal and 50 year anomalies . As such it doesn't show the lurch down over the last few years to its current 0.4anomaly.

It would be very nice to get the Met office into a discussion and discuss such things as Doug's global overview and the situation as it relates to Britain.

May 27, 2013 at 7:25 PM | Unregistered Commentertonyb

BrianC said

"Right, so there is no global warming. Fair enough!

Somebody had better go and tell the glaciers that they can stop receding."
------ ------

Can I respectfully suggest you read a book on climate through the ages to supplement your knowledge of glaciers?

. Any book by Hubert Lamb would do but Ladurie wrote a particularly good one called 'times of feast times of famine' in which he enumerated all the glacier changes over the last 3000 years.

Here they are back to 1540 graphed as a blue line-top of the page retreating, towards bottom of the page advancing.

It only partially captures the retreat from around 1350 to 1550 and misses out the advance around 1215 to 1315, the retreat from 750 to 1200 an advance from 375 to 700 a retreat from 350 BC to 350AD and so it goes on through the Holocene.

Hope this helps to clarify that the latest advance is but one in a long sequence of glacier movements

May 27, 2013 at 7:38 PM | Unregistered Commentertonyb

There definitely is (or has been) global warming, just no man made global warming.

May 27, 2013 at 8:27 PM | Unregistered CommenterWijnand

Of course you won't find a trend if you choose a model which specifically excludes one.

May 27, 2013 at 8:31 PM | Unregistered CommenterSimon


Thanks for taking the trouble to simplify--it has helped a lot.

May 27, 2013 at 9:17 PM | Unregistered CommenterMichael Larkin

Beating a linear trend is not an impressive feat, nobody every thought that temperature rise should be linear when the climate forcing is not linear. But by needing to use an ARIMA(3,1,0) model, Keenan demonstrates that the global temperature record is non-stationary, i.e. that there is a trend in the data. What could possibly cause that trend in the data? Greenhouse gasses?

May 27, 2013 at 9:50 PM | Unregistered Commenterrichard telford

Thanks for your incredible tenacity, Don.
For older blokes such as I who did not go into the civil service or some esoteric branch of scientific research but spent our working lives doing quite mundane but useful stuff, I feel that those really clever but very strange people who popped out of their ivory tower from time to time to tell us ordinary people that we were doing it all wrong and were condemning 'the children' to an awful future are con-men (and women) who put their own interests before those of everyone else.
When the implications of this reach the MSM (if they ever do) it will take a very long time for the general public to trust 'scientists' again.

May 27, 2013 at 10:19 PM | Unregistered CommenterAlexander K

Anthony's focus on the quality of base data should not be forgotten. All the fixes and fiddles have been, not coincidently by any plausible stretch of the imagination, almost entirely in the direction of heightening the impression of a) warming, and b) human influence through CO2 emission.

Compared to the remaining 'corrected' data, sand would be like bedrock to build on.

May 27, 2013 at 10:40 PM | Unregistered CommenterBrian H

Met Office admits claims of significant temperature rise untenable


May 27, 2013 at 11:04 PM | Unregistered Commenterjamspid

excellent work has been done here. Congrats and thanks to everybody who contributed.
Please do not give up till all these frauders are prisoned or working in acoal mine...

May 27, 2013 at 11:13 PM | Unregistered Commenterbesso keks

Ah.. so does this mean I can now definately claim I've been MISS SOLD road tax based on C02 emmissions :D

May 27, 2013 at 11:23 PM | Unregistered CommenterBLACK PEARL

Further to: May 27, 2013 at 2:00 PM | Geckko

The point here is the length of the data set. What is 150 years worth of data in relation to some 4 billion years worth of constantly changing climate?

The fact that there may presently be some upwardly moving trend, does not to me, appear at all surprising. I consider that people overlook the fact that we only have an extremely short snap shot.

May 28, 2013 at 1:51 AM | Unregistered Commenterrichard verney

What is the date that the final response was received. In your opinion, will this data counterfit any of the data in the past and upcoming IPCC reports? Great work!

May 28, 2013 at 2:45 AM | Unregistered CommenterCC Squid

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