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The BBC’s Climate Change By Numbers

March 3, 2015

By Paul Homewood




The BBC broadcast its latest piece of climate change propaganda last night, “Climate Change by Numbers”.

The programme centred around three mathematicians, Dr Hannah Fry, Prof Norman Fenton and Prof David Spiegelhalter, using mathematical techniques to persuade us how dangerous climate change was going to be.

Plenty of flashy graphics were used, and a lot of impressive-sounding words thrown around – matrix algebra, Kalman filters, Monte Carlo methods. Attempts were made to compare the ways that climatologists use these techniques, with the likes of Formula One, Apollo missions, and even Premier League teams.

It was difficult to identify any real substance, however, and there was a noticeable reluctance to address any of the very real issues that are central to the debate over climate change.


The programme centred around three numbers:



A) 0.85C

This was claimed to be the amount of warming since 1880, when the programme claims temperature measurements became standardised.

Hannah Fry spent much time discussing changes in the ways ships took measurements of sea temperatures, and homogenisation and kriging techniques helped to “clean” dodgy data and big gaps in record keeping. Although she admitted that the 0.85C was not exact, and indeed was “symbolic”, she never once mentioned error bars, perhaps a surprising omission for a mathematician.

No mention was made either of the potential effect of UHI over this period.

But most remarkable was the failure to spell out just how little we actually know about the global temperature in 1880, and the years after. As the GISS map below shows, virtually all of the world’s landmass outside of Europe and the US had no temperature records at all. Most of the data shown is oceanic, but even that would be extremely patchy and largely worthless.




Finally, there is no mention or discussion of why temperature changes since 1880 should have any significance. We know that this period marked the end of the Little Ice Age, claimed, in Greenland and Iceland at least, to be the coldest since the end of the Ice Age.

Why was there no mention of the Medieval Warm Period, or the regular cycle of warm and cold periods beforehand?


The section ended with Fry stating that the planet had warmed up since 1880, even if we did not really know by how much. To which my reply would be – “AND?”


The fundamental questions that need to be answered, before we can understand the current warm period, are:

1) Just how much has the planet actually warmed since 1880?

2) How much uncertainty is there in these numbers?

3) How do current temperatures compare with the MWP, and earlier warm periods?

4) How does the rate of warming over the last century or so compare with earlier comparable periods?

5) How much of recent warming has been natural?


The programme had a real opportunity to address these issues. Instead, it seemed to have made its mind up what the answers were before it asked the questions.



B) 95%

“Scientists say that they are 95% sure that at least half of the warming in the last 60 years has been caused by humans”


As any proper mathematician should know, the concept of statistical certainty is an extremely specific and measurable one. Prof Fenton gets off to an extremely misleading start by conflating this with the IPCC unscientific and subjective approach. This is what they say in AR5:





Of course, if he had said “scientists thought it extremely likely”, it might have carried a bit less weight!


Fenton spends a lot of his slot talking about models, for instance using a simplified model to explain how players’ wages affect teams results in the Premier League. He goes on to explain that it is climate models that allow scientists to be so certain that humans are to blame. Would these be the same models that have so grossly overestimated warming?






Fenton’s rather simplistic approach fails to explain why there was rapid warming between 1880 and 1940, before CO2 emissions really took off, and why there was a 30-year pause after the war, when emissions were growing.

He even uses an image of the (non existent) hot spot to prove the human fingerprint!


He rather lets the cat out of the bag when he says that to most climate scientists there is one prime suspect – us. This goes to the heart of the IPCC process.


But even assuming he is right, how scary is half of the warming since 1950 – maybe 0.3C?


C) Trillion Tonnes

“The maximum amount of carbon we can burn to avoid dangerous climate change, i.e a temperature rise of 2C over pre-industrial levels.”


Prof Spiegelhalter splits this section into two segments – how the trillion is worked out and why 2C plus is dangerous.


1) Once again we are back to those models that have failed so miserably. Spiegelhalter recognises their limitations, but maintains that if you lump them altogether you’ll probably get near to the truth.

However, at no stage does he address the issue of climate sensitivity, i.e. how much will temperatures respond to a doubling of CO2. This goes to the heart of the matter, and therefore seems a remarkable omission.

He also fails to mention that the GHG effect is logarithmic. In other words, if a doubling of CO2 adds, say, 1C to temperatures, it would need to double again to add the next 1C. If the effects of the first doubling are manageable, any further problems are pushed well into the future.

Critical to all of this, of course, is the current pause in temperatures. The longer this continues, the more existing models are called into question.


2) Why is 2C dangerous?

Spiegelhalter spouts the usual nonsense about how our weather will become more extreme, with bigger storms, droughts and floods, without providing any data. He certainly offers no evidence that these have got worse in the last century, and totally ignores much evidence that the opposite has occurred.

To be fair, he does make the very valid point that, as climate changes, extremes become harder to predict.

He uses the example of the Thames Barrier, stating that it was designed to protect London from 1000 year floods, but that this was based on only 100 years of historic data. If climate change alters the nature of extreme storms and floods, this could invalidate the calculations.

The problem with this is that climate changes all the time anyway. Just ask anybody who lived through the dustbowl years.

What we need, and have not got, are robust regional climate models. The flip flopping of Julia Slingo, who first stated that climate change would lead to cold, dry winters in the UK, and then a year later said the opposite, should be a salutary reminder to anybody who thinks we understand how our climate works even now.

All in all, he fails to explain how an increase of 2C, (from 19thC levels), should be in any way dangerous, particularly since we have already had nearly half of this with no ill effect, and arguably clear benefits.




The programme missed a big opportunity to confront some of the real issues in the debate over climate change. Unfortunately, it seems the purpose was simply to persuade viewers that they should pay attention to climate scientists and be duly worried.

As this is the BBC, I suppose we should not have expected anything else.

  1. March 3, 2015 6:00 pm

    This blog from Prof. Norman Fenton is interesting:

    • March 3, 2015 7:30 pm

      To sum up

      You can get whatever results you want depending on what statistical model you use! And then you still have no idea.

      • March 4, 2015 12:15 am

        In order to know what is “abnormal”, you must first know what is “normal”.

        So, if you only have a century of data – you cannot possible work out what is abnormal.

        However if you look at CET – you not only have a lot of data – you can also see that the current period is entirely consistent with “normal”.

    • March 8, 2015 2:11 pm

      As QV pointed out my blog posting (see the end) did highlight a number issues that were not covered in the programme including concerns raised here.

  2. March 3, 2015 6:01 pm

    And a complementary figure: “The BBC’s Climate Change By Numbers” compelling evidence that £145.50 is a waste of money.

  3. March 3, 2015 6:01 pm

    blah, blah blah
    same story as before
    how do you reconcile:
    a) no re-calibration [of thermometers] before 1948 compared to prescribed re-calibration from 1970
    b) average of 4-6 measurements a day [thermometer]before 1940’s versus continuous measurements from 1970’s [thermocouples]
    c) human measurements before 1950s versus automatic/robotic recording since 1970s?

    • March 4, 2015 11:18 am

      Did you know USHCN stations still only record twice a day, to the nearest degree?

  4. March 3, 2015 6:10 pm

    Spielgelhalter might think Thames barrier was designed to last 1000 years, wikipedia quotes Environment Agency saying it was designed to last to 2030 BUT because sea levels have been less than the assumed 8mm/year it will last till 2070.

    Presumably barrier wasn’t designed in 1030!

    More here

    • Billy Liar permalink
      March 3, 2015 7:25 pm

      Perhaps the Thames Barrier was designed as monument to extrapolation.

    • mkelly permalink
      March 3, 2015 7:34 pm

      Jeremy, the barrier is not designed to last 1000 years it was designed to handle a 1000 year flood, “designed to protect London from 1000 year floods,”.

      • March 3, 2015 7:57 pm

        Then why did EA say it was only intended to last till 2030 assuming a rate of sea level rise of 8mm/year? Nothing about extreme events was mentioned.

        On the other hand how can anyone work out what a 1000 year flood is?

      • mkelly permalink
        March 3, 2015 8:54 pm

        Jeremy I was only responding to the first part of your post (Spielgelhalter might think Thames barrier was designed to last 1000 years,) which was an incorrect statement by you. I have not read the wiki about the EA.

  5. Paul2 permalink
    March 3, 2015 6:14 pm

    At least they take a position and stand by it. I’d have that rather than all this lukewarmism which has infected the media. Man-made climate change ain’t happening making me an out and out denier. Much rather that than a sceptic.

  6. March 3, 2015 6:23 pm

    There is another climate Horizon program on Wednesday, same place & time.

    • March 3, 2015 6:46 pm

      I thought it was a repeat, but in fact it’s new.
      The BBC seem to be going OTT with CC propaganda at the moment.

      • March 3, 2015 7:28 pm

        Gotta make sure they communicate ‘the science’ in the lead up to Paris.

      • March 3, 2015 11:11 pm

        Orders from above, and the sprog in charge of their pension fund.

    • March 4, 2015 12:18 am

      Watching the BBC is rather like looking back in time to the way this whole debate was “discussed” before climategate.

      The world has moved on and it was about time the BBC and its chosen PC presenters who still don’t understand the basics moved on as well.

  7. Derek permalink
    March 3, 2015 7:30 pm

    Your summary is spot on. If only the BBC would have a balanced programme in which some sort of discussion between experts with different explanations could take place. But this will never happen as it would leave the viewer with the inconvenient truth, that there is no proper consensus on how the climate is going to change, nor what is driving it.

  8. March 3, 2015 7:41 pm

    Regarding Paris

    Seem to remember Monckton saying there was going to be an attempt to get nations to sign a binding commitment, with no possibility of exit, to being regulated by some world wide committee (ie government). Monckton was trying to get every to lobby their mp to ensure there was a clause in any such agreement which allowed the possibility for exiting such organisation.

  9. Bloke down the pub permalink
    March 3, 2015 7:57 pm

    He even uses an image of the (non existent) hot spot to prove the human fingerprint!

    This was the biggest , but by no means only, issue I had with the programme. I wonder if Prof Fenton has been made aware since the broadcast of the accuracy of his claim. More to the point, It would be interesting to hear the conversation between him and whoever fed him this line in the first place.

  10. emsnews permalink
    March 3, 2015 9:59 pm

    The lies never stop because there is a flood of money being made on the global warming scam. Even as Mother Nature proves over and over again, CO2 doesn’t matter at all, they have to pretend it does or the tax on energy and all systems will shut down and many people eating this money will be much poorer.

    So on with the charade.

  11. March 4, 2015 12:13 am

    I stopped watching at the point they said “we will now look at measurements errors [and ignore natural variation].”

    This is the same fraudulent approach used by Hansen to say “because 0.1C of instrumentational error exists – and because HE SAYS all the rest is man-made, that means there’s a 99% chance [he’s an idiot or a fraud]

    There are in fact three different components.

    1. Man-made
    2. Measurement errors
    3. Natural variation

    So, like Hansen I assume the BBC came up with a figure “we are 99% sure it’s man-made [or natural variation].”

    Getting people like this to understand natural variation like teaching people who have no concept of zero how to do maths.

  12. TonyM permalink
    March 4, 2015 2:24 am

    The one number they probably didn’t discuss- “Zero” warming for 17 years. Hard to manipulate that one too much!

  13. THX1138 permalink
    March 4, 2015 4:35 am

    None of this discussion includes the Electric Universe Theory, which very thoroughly shows that the electric currents of the solar system and the universe are the number one driver of all of our weather, and summation of weather they are calling “climate”. If our current weather men understood this, they could, with the proper instruments, very consistently predict the weather, instead of the farce of “prediction” they pretend to do today, based on gaslight-era thermodynamics theories. The fact is, if the solar system happened to drift out of the currently prevalent Berkeland Current, powered locally by the Milky Way Galaxy, all bets would be off, our entire weather and “climate” (the summation of weather, a mathematical construct) would change in a heartbeat. The illusion of continuity we are currently enjoying (albeit unsatisfied with its slight variability, which we might find as uncomfortable), is unpredictable, because of the fact that only a slight change in the galactic electric current would drastically change everything.

    Our Sun and all of its planets are currently the beneficiary of a very cozy current of electricity from the Milky Way Galaxy, which, in turn receives its electricity from the rest of the universe. That’s all we know now.. Our current circumstance is not guaranteed, because changes can occur in the galactic circuit of electricity at any time. We live in a calamitous world, not what what we perceive as a steady, long-term safety of comfort. We know this when we perceive the historical record without bias and incredulity.

    Take heart, though! Life is amazingly adaptive, and we will survive no matter what changes occur in our local environment. How do I know this? Because we are the progeny of people who have survived past calamities and lived to conceive us, and Life proves itself over and over to be persistent throughout any sort of physical ordeal, be it temperature, chemistry or otherwise.

    ▶ Symbols of an Alien Sky (Full Documentary) – YouTube

  14. March 4, 2015 8:57 am

    Great review of the totally biased programme.
    The justifications for the 0.85 deg K rise and the 95% confidence were laughable, or more accurately, cryable.

    Would point out that the Carbon dioxide forcing function is logarithmic as you say only if you accept that the atmosphere is made up of grey gases and that gas emissivities are simply additive. That is if the CO2 and H2O spectra did not overlap, which they do. This well known effect (apart from the climate modellers) substantially reduces the effect of increases in either components on the RFF. However the subject of CO2 causation was carefully avoided. The generation of the RFF which underpins all models is science at its worst ( committee decisions on values to use).

    • Brian H permalink
      March 5, 2015 4:10 am

      Since the first half of the 2°C rise has been beneficial, the smart money sez the second half is likely to be the same.
      After all, it’s Climate Chillin’ that causes droughts and draughts, not Warmin’!

  15. Vernon E permalink
    March 4, 2015 3:24 pm

    I had the same reactions to the same points. But, Paul, even after all this time I’d like to challenge the fundamental premise – that there can be an “average global temperature”. We all know the old “average American has one tit and one ball” true but nonsense. Is there a mathematical definition for what extent a series of variables can be averaged? To me it is impossible to meaningfully “average” equatorial and polar temperatures over an open-ended time span. Surely, the broadest extent that “averaging” can be viable would be at points on the same latitude, at the same time of day and the same time of year. This aspect has been bothering me ever since I started following the subject ten years ago. Are there any mathematicians out there who can help me on the limitations of “averaging”?

    I thought she said “since the industrial revolution” which I took to be around 1830, but others heard 1880. Whichever, mariners did not have the means to measure temperatures to two decimal places!

  16. cheshirered permalink
    March 4, 2015 3:26 pm

    Inclusion of the hotspot – the one that has been noticeably MIA these last few years, was to say the least, astonishing.
    Overall it was like watching one half of a trial – this being the case for the prosecution. There was no cross examination allowed nor was there a defence counsel presentation either, but then we all know why. A well-presented defence would have ripped their ‘case’ to pieces.

  17. Charlie Moncur permalink
    March 4, 2015 4:48 pm

    A well made programme but very one sided. Only looks at temperature since 1880. Assumes a straight line increase in temp vs. CO2. Equation was a log function. Goes into details on Kalman Filters and spatial sampling – all valid mathematical techniques – but not if the raw data is being tampered with. One concern I have with the past is that temperature rise proceeded any CO2 rise. But in industrial era man has pumped CO2 into the atmosphere which did not occur in history. So there is a fundamental difference in the current situation with history where man is forcing the CO2 level. Anybody got an opinion on this and could it indeed influence the rate of warming since 1880?

    • Brian H permalink
      March 5, 2015 4:13 am

      Ya, it should’ve but didn’t. This is called “falsification of the hypothesis”.

  18. 1saveenergy permalink
    March 5, 2015 1:04 am

    Just watched the Helen Czerski Horizon program

    Another well crafted glossy sales pitch, lots of back lit steam, fires winds, burning snow, glacier melts, & David Attenborough (so it must be true), lots of ‘could happen’.

    They did mention the difficulty of modeling clouds & also climate-gate @48min

    Ends with suggesting extreme weather is increasing, & “the consensus is formidable”.

    In 3 words …..Glossy BBC misinformation.

  19. March 5, 2015 2:08 pm

    Helen Czerski’s Horizon programme on the history of the climate scare was a hoot too. I enumerated 14 major lies/omissions on this twitter thread

  20. March 5, 2015 3:50 pm

    Re-Charlie Moncur query about CO2 cause / effect. My views are as below.

    As he says the evidence available is that warming increased CO2 levels historically. Probably seas warming and reduced solubility ??
    Regarding the effect of CO2 increases on solar in / out fluxes; the limited knowledge of radiation of gas mixtures shows that the mixture behaviour depends on overlap of spectra. Carbon dioxide an moisture have similar spectra but water vapour partial pressure is over 10 times CO2 the result of this being that it takes large changes of CO2 to have any effect.

    The IPCC argued that CO2 could be treated as additive as the background was steady; this is a fallacy in every respect but allowed them to generate higher forcing functions. The RFF is the key to the global warming models and is a committee value that can be neither measured nor tested other than as part of a complex model.


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