- Bishop Hill blog

This is a guest post by Doug Keenan

Questions relating to the work of the Met Office on global warming are being put in the UK parliament, and the Met Office is refusing to answer them. Parliamentary Questions have a history going back centuries. Giving answers, or giving a valid reason for not answering, is required. The stand-off is yet to be resolved.

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, 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 the 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. A related Question, from 3 December 2012, effectively resolved the ambiguity. The Answer to the Question stated that “Linear trends … are based on year-to-year variability around trends described as 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 then asked a second time. They did not answer. He asked a third time. Again they did not answer. He asked a fourth time. Still they did not answer. He has now asked a fifth time. The answer is due by April 12^th.

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 is 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, but instead replied largely with rhetoric and a display of gross ignorance about undergraduate-level statistics. For an example, see the Bishop Hill post “Climate correspondents”. Hence, I decided that trying to talk directly with Slingo about the Parliamentary Questions would be a waste of time. Instead, I tried talking with Hirst. I first e-mailed Hirst about this after the third refusal to answer the question from Lord Donoughue. The message 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.

Hirst’s reply to my message was sent after the fourth refusal to answer the question, on 28 March 2013. It is as follows.

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.

My rejoinder is below.

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 12^th. My hope is that if the Met Office continues to refuse to supply the number, HM Government will get the number from elsewhere.

I have not received a reply to that. Additionally, I have been informed that Hirst is away this week and next; so there will be no reply from Hirst before the due date of April 12^th.

The Met Office is obviously being highly obstructionist. The alternative, though, would be for the Met Office to admit that they do not have a statistical model that supports their claim that the temperature increase since 1880 is statistically significant. In other words, the alternative is for the Met Office to admit that the temperature increase might be reasonably attributed to natural random variation.

It is not only the Met Office that has adopted a position like this. The IPCC, in its most-recent Assessment Report (2007), used the same statistical model as the Met Office. 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. The failure implies that the claim that temperatures have been significantly increasing is unfounded.

Thus, the Parliamentary Questions tabled by Lord Donoughue undermine the primary basis for global-warming alarmism. The Met Office is trying for a cover up. In doing so, it is potentially risking a conflict with parliament.

It remains to be seen how matters get resolved. Under the rules of parliament, the person delegated 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”.