A reply to Professor Michael Merrifield of Nottingham University


Recently the good Professor posed a question to me on Twitter. I’m afraid I didn’t identify him at once, but he’s come back and posed it again.

He writes:
1. Sadly, you seem to have got the wrong end of the stick, Roger. My question to you, “Come on Roger, you can do it: show you know at least a little physics and can think at least marginally,” was apropos of a very specific, really rather simple question. Namely, why do NASA’s measurement of rising ocean levels give systematically different answers when they calculate the effect using a gravitational probe as compared to the direct measurement of ocean height? In fact, here’s where I ask it and show the data in question.

If you would care to address that straightforward question, I’d be happy to engage with you on the altogether more complex misunderstandings that you lay out in this blog post.

So I am happy to reply.

Dear Professor Merrifield,

I am sorry that you feel I ignored your question as first asked. I ignored it because it seemed completely irrelevant – and also, I have to say, because it seemed to me to be couched in rather patronising and divisive terms. (People who take debate seriously do not usually start out by characterising their opponents’ arguments as “misunderstandings”). I have not written – at least recently – about the issue of sea level rise. I do not claim any expertise in the area. I have no experience of gravitational probes. And I see no reason to answer trick questions from astronomers – or indeed from Journalists. I think that George W. Bush was perhaps ill-advised to take a question on who was the Prime Minister of India, which he failed to answer on the spur of the moment.

I am a politician, not a scientist, but as a politician I try to be aware of sources of information. If I were seeking an answer to your question, I might well enquire of Nils-Axel Mörner, whose work I have read and who seems to understand the issues.

The fact is that I simply don’t know why there is a large discrepancy between the trajectory of sea level based on satellite observations, and that based on direct measurements, though I note that it is discrepancies of this sort that engender doubts about some of the confident assertions of climate scientists.

If you want me to speculate, I will. I guess there may be some read-across from the similar discrepancies between mean global temperature figures based on ground stations and based on satellites. Ground stations don’t give anywhere near universal coverage, and those who manage the data are all too willing to interpolate. The available set of ground stations varies over time (many cold-climate stations were lost on the break-up of the USSR, for example). Moreover the immediate microclimate of individual ground-stations varies over time. You will be familiar with the research that finds that urban sprawl and air-conditioners and tarmac have influenced many ground stations. For these reasons I feel that the satellite data have more credibility.

The problems with local measurements of sea level are even more severe. Natural movements in the sea (waves and tides) are orders-of-magnitude greater than the couple of millimetres a year which you’re trying to measure. Local topography and local weather influence currents and sea level in all sorts of unpredictable ways.

Then of course you have the question of tectonic plate movement. We hear how sea level rise is affecting Bangladesh, but few people recall that the relevant tectonic plate is being subducted (under the India plate, if I remember), so the issue is less the sea rising than the land subsiding.

Nor should we ignore tectonic effects in the UK. The village of Dunwich  disappeared under the North Sea centuries before the current slight warming – we can hardly blame that on anthropogenic emissions.

The big picture on sea level rise is that at the beginning of the current Interglacial, ten to twelve thousand years ago, there was very rapid glacial ice-melt which led to serious sea level rise – hundreds of feet in a few hundred years. This inundated the open country where the North Sea now is, and it created the English Channel. Since that time, the rate of rise has generally declined, and is now at a very low level indeed, which may be primarily an issue of thermal expansion.

It is interesting to reflect on the status of small islands and coral atolls, whose leaders will be in Paris shortly with their begging bowls, demanding climate reparations from Western countries. Do you believe that all these islands were exactly the same 400 feet (or so) above sea level in 10,000 BC, and that it’s just coincidental that they’re all a few feet above sea level now? Or do you recognise (as Darwin did) that coral atolls grow with sea level, and will always be roughly the same height above the surface?

Of course it is true that there is some melting of glaciers and ice caps, which might cause sea level rise (though the Arctic ice-cap is mostly floating, so will not add to sea level). But there is good geological evidence that glaciers advance in cool periods and retreat in warm periods (so far so obvious), and it seems overwhelmingly likely that the ice caps behave in the same way. As the world did not drown during the Minoan Optimum, or the Roman Optimum, or the Mediæval Warm Period, I feel very confident that it won’t drown in the current 21st Century Optimum.

And now, Professor Merrifield, you may pull your rabbit out of your hat and explain to a waiting world how you explain NASA’s discrepancy.

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27 Responses to A reply to Professor Michael Merrifield of Nottingham University

  1. Linda Hudson says:

    In no way am I science savvy, but my human natural instinct tells me that the plunder of earthly resources, and pollution of earth sea, and sky are more in the control of humans, than being in the control of the elements.
    The world can replenish, and recover if given time, and with good housekeeping.
    Climate change scare mongering can, and is being used for the high profits being made in global green taxes, and does not change one jot of the worlds huge production, of the car, and their emissions, and the human hunger for energy.
    Green taxes are a bit like the V.W. crooked emission fiasco!

  2. Ex-expat Colin says:

    Its physics alright…the physical fiddling type:

    Professor Nils-Axel Mörner as follows.

  3. Ffred123 says:

    Well done Roger , I could actually understand your response.
    As somebody who has no scientific knowledge to achieve that you did more tha good, nearer excellent

  4. Christopher Browne says:

    I just dug this out of my files

    .Letter printed in the Daily Mail Thursday 30th December 2009.

    “Is this a sea change?

    DR NILS-AXEL MORNER, former head of paleogeophysics and geodynamics at Stockholm University and leader of the Maldives Sea Level Project, says he found the sea level around the Maldives had risen by about 1 mm a year between 1850 and 1940 after that there was no change until 1970 when the sea level fell by about 20cm and hasn’t changed since in the past 35 years.

    Using satellite altimetry, Dr. Morner showed there was no trend in the change in sea-level around the globe. The IPCC report showing a rise of 2.3mm in 2003 was because fictional ‘data’ had been used.

    When he was about to leave the Maldives, Dr. Morner made a programme for Maldives TV re-assuring residents that the sea level wasn’t rising. The Maldives government banned the broadcast – it would have meant losing money from Western governments.

    A tree on an island that had been there since 1950 was pulled down by an Australian (pro-IPCC) sea level team because it was clear evidence that the sea-level wasn’t rising. According to Dr. Morner, true sea level specialists agree there might be a rise of 10cm (plus or minus 10cm) in 100 years, but this is at odds with current ‘official’ reports of a rise of 30ft.

    Who do we believe? A scientist eminent in his field or a team whose funding depends on giving the ‘correct’ answer?

    Politicians shouldn’t be misled by dodgy reports which haven’t been independently reviewed.


    Blackburn, West Lothian.”

    • catweazle666 says:

      “A scientist eminent in his field or a team whose funding depends on giving the ‘correct’ answer?”

      Where “correct” equals the result that ensures the trillion-dollar-per-year AGW gravy train keeps right on rolling?

    • Linda Hudson says:

      Believe the Swede, he has a fight on his hand because he tells it as it is, and will be hounded for it!

  5. catweazle666 says:

    It must be remembered that unlike the tide gauges that give direct measurement, the satellite sea level *estimates* are totally reliant on complex computer analysis and modelling of highly theoretical – and AFAIK unproven – gravimetric calculations to produce their results.

    Now come on Roger, if it is a choice between a £10 ruler and a £1,000,000,000 supercomputer/satellite system, which would you believe – especially if your salary/grant application depended on it?

    • Michael Merrifield says:

      Actually, they measure it pretty much directly. It’s almost as if those scientists were quite smart and knew what they were doing…

      • catweazle666 says:

        “Actually, they measure it pretty much directly.”

        Actually, they don’t.

        Not even close.

        Nor are they particularly accurate in comparison with direct measurements.

        The measurement of long-term changes in global mean sea level can provide an important corroboration of predictions by climate models of global warming. Satellite altimeter radar measurements can be combined with precisely known spacecraft orbits to measure sea level on a global basis with unprecedented accuracy. A series of satellite missions that started with TOPEX/Poseidon (T/P) in 1992 and continued with Jason-1 (2001–2013) and Jason-2 (2008–present) estimate global mean sea level every 10 days with an uncertainty of 3–4 mm.


      • catweazle666 says:

        Oh, and as for scientists knowing what they’re doing, my knowledge and training in the application of some very advanced science stood me in good stead throughout my somewhat successful career, so go and patronise somebody else, sunshine.

      • Michael Merrifield says:

        Then I am sure you’d know that radar measures distances very accurately an straightforwardly using the light travel time from a satellite on an orbit that are precisely determined — no “complex computer analysis and modelling of highly theoretical – and AFAIK unproven – gravimetric calculations to produce their results” required.

      • catweazle666 says:

        “Then I am sure you’d know that radar measures distances very accurately an straightforwardly using the light travel time from a satellite on an orbit that are precisely determined”

        I know precisely how the satellites determine sea level, and your “understanding” is so simplistic as to be entirely laughable.

        For example, you appear to believe that the surface of the sea is flat and to be a perfect reflector.

        It is neither.

      • Michael Merrifield says:

        The fact that it doesn’t have a 100% reflectence reduces the returned signal; the fact that it isn’t flat means that there is a dispersion in the returned pulse that is averaged to obtain the average distance within the beam. In what way do either of these factors mean that the measurement isn’t straightforward to interpret?

  6. Ex-expat Colin says:

    As far as I can tell the difference between the two measurement systems is about 1.2mm pa. Various highs/lows through the measurement period.However, where firing an EM wave at the sea/oceans I would not expect to return a precision distance. We are talking millimetres here. Any other compensations to be made?

    • Michael Merrifield says:

      If it were down to the precision (or, more strictly, accuracy) of the measurement, you wouldn’t expect to see the systematic deviation that the data displays. I agree, though, that it is amazing that they can measure sea level that accurately.

  7. Charles wardrop says:

    Measured, convincing response to an (?) Academic whose writing style looks as if made after a very large g&t.
    Accordingly, scores “Helmer: 10, ” “Merrifield : 2,” a score reflecting neither his insight nor his manners, but his providing R.H. with the opportunity to expound balanced good mann,ers and sense!

  8. Michael Merrifield says:

    Not a trick question at all: you made play of your A-level qualification in physics, and this would only require a sub-A-level knowledge of the subject, even based on current syllabus, so I thought it would be interesting to call you on it. Would you like a clue? OK, here it is: you won’t like the answer.

  9. Dear Michael, I am perfectly happy to engage in a realistic debate with you about the issues, but I am not going to engage with you on random and irrelevant questions, whether you agree that they are “trick questions” or not.

  10. Derek says:

    Come on Professor, the suspense is infuriating. Explain the point you are making so we can understand its relevance.

    • Michael Merrifield says:

      Oh come on, Derek, surely you can do better than Roger! What might cause the volume of a body of water to increase without changing its mass?

    • Ex-expat Colin says:

      What he wants to extract from you is in the link below Derek, 2nd para.


      There’s clearly money in measuring..keeps somebody in work I suppose? I don’t think I would relish relying on those measurements though.

      • Michael Merrifield says:

        Personally I would rather rely on the careful measurements of smart scientists (who, if driven by greed, would have been earning a great deal more doing financial modelling in the City) than conspiracy theory.

  11. ps3person says:

    I have to question any academic who couches a question in such an insulting and frankly, unintelligent manner. If I want a question answered, I remain polite and simply ask the question, as I’m certain most people do. It is rather pathetic that this professor appears unable to disguise his disapproval of UKIP or Roger Helmer.

  12. chris moffatt says:

    signal = 1.0 – 2.0mm/pa measurement error = 3.0 – 4.0mm/pa. Hard to spot anything there. However I will tell Prof Merrifield that the major components of sea level rise in the lower Chesapeake Bay area where I live are:
    compaction of landfill on which many localities (eg Norfolk, VA) were built
    ground water depletion by too many wells (salt water intrusion as far as Sandston, VA >60 miles away))
    post-glacial rebound (look it up, it’s a thing)

    None of these factors require a change in total mass of ocean/sea/estuarine/tidal waters around the world.

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