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Jones: post 1995 warming "significant"

Phil Jones has announced that post-1995 warming is now "significant", with new data changing the picture he had previously reported to Roger Harrabin. The news comes via Richard Black, in one of those "we don't want anyone disputing this, so we've switched commenting off" articles.

By widespread convention, scientists use a minimum threshold of 95% to assess whether a trend is likely to be down to an underlying cause, rather than emerging by chance.

If a trend meets the 95% threshold, it basically means that the odds of it being down to chance are less than one in 20.

Last year's analysis, which went to 2009, did not reach this threshold; but adding data for 2010 takes it over the line.

I wonder what he makes of the Koutsoyiannis paper then?

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Reader Comments (86)

If Phil says so it must be so. (sarc)

Jun 10, 2011 at 2:34 PM | Unregistered CommenterKon Dealer

The news comes .... in one of those "we don't want anyone disputing this, so we've switched commenting off" articles.

You mean a news article .

Jun 10, 2011 at 2:42 PM | Unregistered CommenterHengist McStone

This is really desperate stuff, revealing a complete lack of statistical competence.

Jun 10, 2011 at 2:44 PM | Unregistered CommenterNicholas Hallam

In his obvious excitement, Richard appear to have forgotten to ask the rate of warming, since 1995, and the decadal rate say since 2000...

ie it is rather a bit lower than 0.2C per decade required to fit projections...

Ot is it a statisically significant, negative rate of warming since a certain date.. ;) !!! Richard won't know or care he's got his story.

Is anybody good with the woodfortrees website, and can link a graph showing the rate since 1995, since 2000, etc?

Jun 10, 2011 at 2:47 PM | Unregistered CommenterBarry Woods

Nicholas Hallam

This is really desperate stuff, revealing a complete lack of statistical competence.

I think it goes well beyond incompetence.

Jun 10, 2011 at 2:55 PM | Unregistered CommenterDon Pablo de la Sierra

The article is full of lies:


'Since then, nothing has emerged through mainstream science to challenge the IPCC's basic picture of a world warming through greenhouse gas emissions.'

What about the Spencer and Braswell paper on Climate Sensitivity or the work Svensmark where a link has been established with cosmic rays to cloud formation. The BBC should be ashamed, pathetic it really is.

I am certainly glad I don't live in Hengists world where by any contrary evidence is met with an Iraqi information minister type response.

Jun 10, 2011 at 2:55 PM | Unregistered CommenterJack Cowper

It's really not suprising that adding in a large El Nino year at the end tips the balance in favour of significance. I expect a non-significant trend will reappear in a year or so but I don't expect Phil Jones to be rushing to tell anyone about it.

Jun 10, 2011 at 3:03 PM | Unregistered CommenterDaveJR

So is the rising temperature reason why its so unseasonably cold and wet outside my Surrey window right now?

Jun 10, 2011 at 3:04 PM | Unregistered CommenterLatimer Alder

"But another year of data has pushed the trend past the threshold usually used to assess whether trends are "real"."

doesn't seem to mean any new warming has actually been detected but just that the bigger the numbers of your statistical polulation the lower the level of significance needed to claim"significant".

This is clear duplicity but perhaps if the government were to offer me £13.7 million I would be tempted too.

Jun 10, 2011 at 3:07 PM | Unregistered CommenterNeil Craig

To put explicitly what others have alluded to: significance at the 95% confidence level (2 sigma) is generally accepted as the threshold for saying "gee, this looks interesting, more research is justified to see if we can tighten up those bounds a couple more sigma and see whether there's really anything here or not".

It is most definitely NOT grounds fir saying something is proven beyond reasonable doubt or to a level warranting policy action.

Jun 10, 2011 at 3:08 PM | Unregistered CommenterBruce Hoult

@Latimer Alder
The unseasonably cold and wet outside your Surrey window right now is called 'weather'. The projections are for a rising temperature in the climate which if you read Richard Black's article is a much longer term trend than the weather.

Happy to help

Jun 10, 2011 at 3:17 PM | Unregistered CommenterHengist McStone

Bruce Hoult

No, Bruce, it is the "first you don't succeed, try, try, try, try, try again" approach which is flying directly in the face of standard statistical procedures and assumptions. Of course, with Post Normal statistics, which Jones is a master of, you not only get to repeat the experiment until you by random chance get a result, but you also get to chose your data (aka cherry picking) as well as the result you report.

Remember that the significance level is saying "having done this experiment once , what is the probability that this is the case?" If the chance is 5 out of 100, that means you have 95% confidence. But if you run the experiment 100 times, find 5 results you like, pick one and say "See! HERE'S MY PROOF" you are going well beyond statistical incompetence -- you are a fraud.

Jun 10, 2011 at 3:28 PM | Unregistered CommenterDon Pablo de la Sierra

@Barry Woods

I've plotted the data since 1995 and 2000, plus the linear trends, in Wood for Trees: see here.

Jun 10, 2011 at 3:28 PM | Unregistered CommenterTurning Tide

Can anyone explain the significance of using 1995 as a start-point? Was it the date of an IPCC report, or something else?

Jun 10, 2011 at 3:39 PM | Unregistered CommenterDead Dog Bounce

I think you guys should read this alongside Richard Black's piece

It show just what a biased and incompetent disgrace of a journalist Black is. Wasn't Whitehouse once the BC's environment correspondent, the post that Black now holds. If so then the difference between the quality of the two is stunning.

Jun 10, 2011 at 3:42 PM | Unregistered CommenterPepete

What IS significant is that global temperatures are decelerating (as CO2 continues to rise), and the pace of warming is less than the IPCC predictions, as shown by Clive Best:

Jun 10, 2011 at 3:42 PM | Unregistered CommenterDon B

It's as if Cohn and Lins never happened - though it is cited in the IPCC 2007 report. The significance of the trend will depend on the underlying model. Jones seems to be assuming a linear trend with white noise, but this clearly won't do because of the serial correlation of the residuals. The series needs to be differenced.

This is quite apart from Don Pablo's observations which also have force.

Jun 10, 2011 at 3:50 PM | Unregistered CommenterNicholas Hallam

Another personal triumph for Professor Jones

If you add one year, 2010, you add significance, according Jones, especially if it happens to be an El Nino year.

Now if you add another year, or part of year, 2011, a La Nina year, does that mean you end up with less significance?

Signficant one year, not signficant the next. How significant is that?

Jun 10, 2011 at 4:05 PM | Unregistered CommenterMac

In the most-recent Assessment Report from the IPCC, Chapter 3 includes an Appendix that describes the statistical method used by the IPCC for evaluating the significance of trends in temperatures. I used that method to check whether the trend during 1995–2010 was indeed significant. In fact, the method shows that the trend is not significant. The claim of Jones is false.

I have e-mailed Phil Jones the details and asked for comments.

Jun 10, 2011 at 4:10 PM | Unregistered CommenterDouglas J. Keenan

How insignificant is this statistically significant warming, in comparison to the lack of correlation with IPCC model projections?

Jun 10, 2011 at 4:19 PM | Unregistered Commentergolf charley

"Can anyone explain the significance of using 1995 as a start-point? Was it the date of an IPCC report, or something else?"
Jun 10, 2011 at 3:39 PM | Dead Dog Bounce

The significance is that early last year he was asked a somewhat cherry-picked question regarding whether there had been warming since 1995. He answered, truthfully and accurately, that there had been no statistically significant warming since then.

Every ignorant man Jack and Harry since that point, the World over, that (for some reason) wants to try and convince people that AGW isn't happening, has been using and abusing this quote as 'proof' that we're not warming anymore. In fact, the majority of people using it are so entirely unaware of its context, that they believe it means the climate is cooling.

It's a cherry picked quote used against climate science, and I've seen it said umpteen times on this website.

Almost never, I noticed, challenged by anyone here.

Oddly enough, now that it undermines that tool that has been used to beat climate science with so many times, you're all jumping out of the woodwork to pick holes in it.

To answer your question Dead Dog Bounce, the significance is the matter of significance.

Question for the rest of you who have rushed in to criticise Phil Jones over this release. Why were you not making exactly the same criticisms of people who have been trotting out the 'not warmed since 1995 - Phil Jones said so' on this very site?

Strikes me, once again, that you are critical only of things which don't agree with you, and unquestioningly swallow whole, anything which can be made to seem to support you.

The exact opposite of scepticism.

Jun 10, 2011 at 4:19 PM | Unregistered CommenterZedsDeadBed

"Strikes me, once again, that you are critical only of things which don't agree with you, and unquestioningly swallow whole, anything which can be made to seem to support you."

Yep, we're jus' like you, Zedsie.


Jun 10, 2011 at 4:29 PM | Unregistered CommenterBad Andrew

Cooler from 2001.

"Looking at atmospheric data, which is independent of the weather station data used in HadCrut3 (I am grateful to Lubos Motl for these figures), from RMS AMU between January 1979 and 2011 the increase was 0.14 deg per decade. However, the figure for 2001 – 2011 is minus 0.04 deg per decade. That is, if anything, the world has got cooler, although still within a statistical constant line within errors of measurement."

Jun 10, 2011 at 4:33 PM | Unregistered CommenterBruce

Zed and Hengist

So there might be a trend emergin in the data. But the IPCC models still seem to be biased very high against the actual data though. What do you feel about that?

Jun 10, 2011 at 4:34 PM | Unregistered Commenterdiogenes


Dr David Whitehouse was a BBC science correspondent, i.e. scientifically qualified.

Richard Black is a BBC environment correspondent and to my knowledge he has no scientific qualifications, just like the others, Harrabin and Shukman. So the three of them just report what they are told and cannot add any scientific value to anything.

Jun 10, 2011 at 4:40 PM | Unregistered CommenterPhillip Bratby

I am curious, how much of 2010 did Jones use to test for significance?

Jun 10, 2011 at 4:44 PM | Unregistered CommenterMac

This is what I would call a "just in time" news release.

With 2011 temperatures developing as they are, Jones was running out of time to make this breathtaking new release.

And then 1995 was a strange year to "cherry-pick" as starting point.

Why not the start of the new millennium, January 2001?

Because this would have shown an equally "significant" (or "insignificant"?) cooling?


Jun 10, 2011 at 4:58 PM | Unregistered Commentermanacker

The desperation is naked.

It is as if they did their temperature math just to generate headlines, in the first place.

How can you say , 'yeah, there are natural ups and downs' and then turn around and say, 'we did the latest math, the trend is up'? How can you? Disgusting.

Jun 10, 2011 at 5:00 PM | Unregistered CommenterShub

I suspect Jones "cherry picked" 1995 as much as his questioner. That was part of what did, at the time look like an impressive upward trend ending in 1998.

1998 was subsequently described as an "outlier" thus "explaining" why later years were lower, but at the time they were cock a hoop.

If Jones had been held to comparing with 1998 instead of 1995 he would have had to say "there has been significant cooling since 1998" which is even worse for his case than no change since 1995.

Jun 10, 2011 at 5:08 PM | Unregistered CommenterNeil Craig

The BBC has to stay on message - its pension funds depend on climate alarmism. Richard Black is desperate to stay on message, regardless of the truth. The BBC should be privatised and then our money wouldn't be used to fund the false message. See

Jun 10, 2011 at 5:14 PM | Unregistered CommenterPhillip Bratby

@Don Pablo de la Sierra,

I don't know why you said "No, Bruce" when I already know and agree with everything that you then added.

Something having only a 1 in 20 possibility of happening by chance is interesting enough to take a closer look at, but it's going to happen purely by chance far too often to say that it's proven.

Jun 10, 2011 at 5:20 PM | Unregistered CommenterBruce Hoult

Mr Keenan, how difficult is the calculation you discuss in your comment above?

Would you be prepared to publish the calculation either at a site of your own, here, WUWT or Climate Audit?

Jun 10, 2011 at 5:34 PM | Unregistered CommenterDead Dog Bounce

Why should a ststement by Professor Jones have any credibility? I'm in agreement here with Professor Muller of Berkeley, "there are some folks papers that I don't read anymore".

Professor Jones, and his "hide the decline", e-mail deletion, and "refusal to share data" antics means that I wouldn't rely on him giving me the time of day accurately.

Jun 10, 2011 at 5:52 PM | Unregistered CommenterArthur Dent

@Dead Dog Bounce

1995 is significant because LubosMotl says so. He calculated that the significance level would safely fail using data from 1995 to 2009 . The question was then put by Harrabin to Jones last year , and the rest is history. It's worth remebering though that several of the questions were framed by skeptics . So much for the argument that skeptics are kept out of the BBC output

Jun 10, 2011 at 6:07 PM | Unregistered CommenterHengist McStone

"In case you missed the point, Mann, Briffa and apparently now Phil simply chop off the inconvenient data and replace it with upslope data. These ‘divergence’ issues are widely widely widely known and discussed in paleo literature and the SOB Phil Jones knows exactly what he meant!!! He was just too honest in his email."

From here.

Jones is as legitimate as "Mann of the loon", his whole department is discredited.
The CRU, have been exposed for what they are - just like the Hadley Centre - civil servant's in HMG's/USGov pay.
Who cares what 'Jones in decline' says? the public have moved on, the real fight now, is with the rising domestic fuel prices in the UK and busting the renewable's/climate change act before the country 'closes' for good.

Jun 10, 2011 at 6:08 PM | Unregistered CommenterAthelstan

The Carbon Brief has it.. - very quick off the mark.

So expect the world's media to pick up on it and all the alarmist blogs....

Jun 10, 2011 at 6:08 PM | Unregistered CommenterBarry Woods

Once again, ZBD demonstrates a lack of scientific understanding. Cherry picking is almost universally used as a tool to disprove a theory. Newtonian physics is probably 'correct' in 99% of instances. It is the 1% of instances where it breaks down. The theory was disproved by looking at the 1% of instances where it could not accurately predict the outcome.

If a theory is correct, it is not possible to cherry pick holes in it. The theory if correct will always provide an explanation for what is observed in the cherry picked example.

For my part, I thought that the key admission by Phil Jones in that old interview was not the post 1995 point, but rather that he accepted that there was no statistical difference between the first part of the 20th century warming and that of the 2nd part of the 20th century warming. The first was not caused by manmade CO2 emissions and he was unable to explain what caused the warming observed in the first part of the 20th century and why and how it had been switched off and replaced by CO2 forcing during the 2nd part of the 20th century.

Jun 10, 2011 at 6:24 PM | Unregistered Commenterrichard verney

I find it curious that 1 extra last sample changes the conclusion when a low pass filter is used (Keenan link, above) that eliminates 2 sample wide anomalies ?

Sir Nurse to explain in a next documentary

Jun 10, 2011 at 6:26 PM | Unregistered CommenterBart Verweggen

I'm going to make my start point 1998...

Look!! There is a statistically significant temperature decrease over the last 13 years.

That's cherry-picking says Phil. You can't do that, you're not a climate scientist!

Jun 10, 2011 at 6:31 PM | Unregistered CommenterDon Keiller

I'm rather bemused by the article. 1995-2009, no significant warming, 1995-2010 significant warming and perhaps 1995-2011 no significant warming depending on this years temperature. Who knows! Adding a year to the trend and suddenly claiming significance as the headline asserts ('Global warming since 1995 'now significant') really shows a complete lack of understanding of linear regression, let alone the nature of the data.

Jun 10, 2011 at 6:32 PM | Unregistered CommenterPaul Dennis

@Dead Dog Bounce

Following is an R session showing the statistical calculations. The temperature data (HadCRUT3) was downloaded from the CRU web site today.

> t9510<- ts(c(0.275, 0.137, 0.352, 0.548, 0.297, 0.271, 0.408, 0.465, 0.475, 0.447, 0.482, 0.425, 0.402, 0.325, 0.443, 0.476), start=1995)
> library(nlme)
> confint(gls(t9510 ~ time(t9510), cor=corARMA(p=1,q=0)))
                    2.5 %     97.5 %
(Intercept) -48.929568004 4.37230179
time(t9510)  -0.001989347 0.02462824

As shown, the 95%-confidence interval for the slope of the line includes 0. Hence the trend is not significant.

Jun 10, 2011 at 7:06 PM | Unregistered CommenterDouglas J. Keenan

richard verney

Just about any theory is "wrong" in that you can find something grossly wrong with it. To use your example, Newtonian physics, it doesn't explain the activities of light, atoms and the such. So we have quantum mechanics and the Standard Model, which in turn is "wrong" because it does not explain gravity (at least yet.)

However, both theories are very, very useful and work well enough for 99.99% of the use we put them to. This is not at all true in Climate Science, which is totally useless. Predictive power is the issue, not perfection.

Bruce Hoult

Something having only a 1 in 20 possibility of happening by chance is interesting enough to take a closer look at

I think you missed my point. This is true only if you do the experiment ONCE. Doing the experiment twenty times invalidates the statistics. What statistics is all about is estimating the characteristics of the populations you are sampling and then using that information to estimate the chances of the sample being from more than one population. This assumes a random sample with no biases, or at least biases you know and correct properly correct for such as converting scales. It also assumes that you don't keep on trying until you get the desired result.

If you want more precision you have larger sample sizes, not repeated sampling.

And when you throw in cherry picking, it is now fraud.

Jun 10, 2011 at 7:37 PM | Unregistered CommenterDon Pablo de la Sierra

As far as I can see, Jones is not so much a scientist, being more of a geographer specialising in climate records and summaries. Nothing wrong with that, but it does weaken his standing as an authoritative source on scientific, predictive matters based on insight into mechanisms. His history of scheming and evasion as illuminated by the Climategate Manuscripts weakens it still further. The report by Black displays a poor grasp of what is meant by statistical significance, and gives more weight to the 5% level than statisticians would commonly entertain. I think the CO2 Alarm Industry suffered in the spinning stakes because of Jones' earlier admission on temperature rises and statistical significance, and that has no doubt motivated this childishly over-excited piece trying to rebuild a castle in the sand. Given the general gentle overall warming trend of the past 150 years or so in some global temperature estimates, there would be no surprise to see it continued. I wonder if that trend was used as the null hypothesis. I wonder how they view the declining trend on the thousands of years scale of the Holocene. I wonder how their methodology would have handled the shorter term coolings and warmings of the 20th century.

Jun 10, 2011 at 7:41 PM | Unregistered CommenterJohn Shade

Did anyone notice that Richard Black dragged in a three month old link to the guardian, ie 2% of datas earlier conclusions (BEST), to give it a bit more spin

"And a new initiative to construct a global temperature record, based at Stanford University in California whose funders include "climate sceptical" organisations, has reached early conclusions that match established records closely."

Jun 10, 2011 at 8:46 PM | Unregistered CommenterBarry Woods

DaveJR : It's really not suprising that adding in a large El Nino year at the end tips the balance in favour of significance. I expect a non-significant trend will reappear in a year or so but I don't expect Phil Jones to be rushing to tell anyone about it.

What I can't believe is that we are still accepting being robbed blind using the "fact" that, adding 2010, we might see an increase in "planetary hotness" of a couple of thousandths of a degree. Maybe more, If HARRY does the maths.

What is it with some of you. Science left the room a long ago. Jones is another HOD finding that the more FUD his monkeys create, the more money flows to his department. Not wanting to loose their jobs, the UAE beancounters mobilise to support the biggest money spinning arm of UEA. Not wanting to loose their new taxes, HMG gives us "enquiries" into climategate. At what point are some of you going to see the visible EM?

Jones is another "useful idiot" who will be remembered along with many others for the vast numbers of people he helped into the next life for a small bag of silver coins.

(If Jones is still contemplating suicide - may I suggest Hypothermia - might give him a reality flash)

I'm frankly tired of arguing "the science" of two thousandths of a degree warming while two thousand die in the freezing cold Northern winter. "Ministers" hand boxes of cash to friends, family and supporters. We argue over 1000ths of a degree. Someone is getting what they want...

Jun 10, 2011 at 8:49 PM | Unregistered Commenter3x2

No wonder real scientists view climate "science" in the same vein as astrology! What a pitiful person Phil Jones really is.

Jun 10, 2011 at 9:17 PM | Unregistered CommenterCinBadTheSailor

But what about post-1998 warming - why pick on 1995?

Jun 10, 2011 at 9:17 PM | Unregistered CommenterIan E

Must be time for Phil & CRU to apply for next year's funding . . . need to crank up the fear factor.

Jun 10, 2011 at 9:44 PM | Unregistered CommenterFred from Canuckistan

We are told repeatedly here in Australia that decadal "trends"..up or down.. are meaningless...yet you can add 5 years to the "trend" and now it has meaning..
10 year "trend"=nothing
15 year "trend" =very important.
Unbelievable..thank god the msm is all over this asking the hard questions. :)

Jun 10, 2011 at 10:53 PM | Unregistered Commentermike Williams

I've just read this article on the GW Policy Foundation website which must have been coincidental in its posting on the same day as the BBc report. It completely demolishes Mr Black's story. The BBc should employ people like that to counterbalance Mr Black.

Jun 10, 2011 at 10:59 PM | Unregistered CommenterM Stone

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