A Möurnful Application of Care and Skill

Not long ago WUWT reported on a paper published by Nils-Axel Mörner and Albert Parker. It’s their attempt to argue that sea level isn’t accelerating, and that sea level rise is nothing for Australia to worry about. They do so by disputing any data that disagrees with their thesis, mentioning as many confounding factors as possible (whether relevant or not), and presenting a sorry excuse for proper “analysis.”


The line I found most amusing was their statement that “A tide gauge record must be analysed with care and skill.” As an example they present the tide gauge record from Fremantle, Australia. I must admit I’m impressed by the care and skill they applied to these data in order to accomplish the goal of concealing the truth of how sea level is changing at this location.


The tide gauge record from Fremantle (15 km SW of Perth) provides a very informative record (Figure 2). It shows fluctuating over a 113 year time span. This indicates that one cannot obtain meaningful trend values from shorter segments like tha last 10 to 20 years. We provide two different alternative analyses; viz. (1) a long-term mean trend analysis (Figure 2a) and (2) a dynamic analysis (Figure 2b).

The “long-term mean trend analysis” is just a linear regression fit to the data. That’s plain vanilla, except for the fact that they neglected to remove the (rather large and completely obvious) annual cycle from the data, an omission which reduces the accuracy of the result. No big deal really.

What’s truly fascinating, in fact absolutely spellbinding, is their “dynamic analysis.” It’s displayed graphically in their Figure 2b (click the graph for a larger, clearer view):

Morner_fig2b

The purple line is what they claim is the likely “local subsidence factor in the order of 1.4 mm/year” (more about that later) while the yellow line is their “dynamic analysis.” Boy oh boy is it dynamic!

Here’s a clearer view of their “dynamic analysis” with their signal in red (which I think is a bit easier to see than yellow, click this or any of the graphs for a larger, clearer view):

Mornerfit

Their dynamic analysis is a least-squares fit of a continuous, stepwise-linear function. They state that the moments at which the slope changes are 1913, 1956, 1993, and 1998. However, zooming in on their figure shows that the final “slope-change point” isn’t 1998, it’s 1997.3:

Morner_fig2b_stretch98

The question naturally arises, how did they choose the slope-change moments?

Alas, they give no clue at all how they chose their slope-change points. Here’s my guess: 1913 and 1956 were chosen by visual inspection of the graph, but 1993 and 1997.3 were chosen specifically because that gives a low slope value after 1997.3. The value was extra low in 1993 and extra high at 1997.3, so that drives up the final slope-change point, which in turn reduces the slope of the final time segment. That of course makes it cherry-picking: selecting their slope-change moments for no other reason than it makes their model look the way they wanted it to look.

Here’s the rate of sea level rise according to the Mörner/Parker model:

Morner_rate

Note the ridiculously high rise rate from 1993 to 1997.3. My opinion: they did that so they could raise the final “slope-change point” in order to reduce the final slope. Mission accomplished.

It’s especially ironic that they would choose their slope-change points to include 1993 and 1997.3, moments spaced less than five years apart, after having protested that “one cannot obtain meaningful trend values from shorter segments.”

If we use those same change moments, but instead of fitting a continuous piecewise-linear function simply fit a piecewise-linear function, we’ll get the linear regression slopes for their separate intervals:

Morner_slop

I think that illustrates just how ridiculous is their choice of isolating the interval 1993 to 1997.3, and how strongly it tends to raise the final slope-change point (and therefore lower the final slope).

What would we get if we analyzed tide gauge data from Fremantle in order to find out how it’s really changing, rather than to support some desired outcome? First of all, there’s a whole year more of data:

Fremantle

Notice what it did during the most recent year of data?

We can linearly de-trend the data, then compute a Fourier transform, to check whether or not there’s really an annual cycle:

Fremantle_dft

Yes there is. It’s amplitude is about 220 mm, as we can see from a “folded plot” of the linearly detrended data:

fold

When we remove the annual cycle to define anomaly values, we get a clearer view of the long-term changes:

anom

Notice what it’s been doing lately?

To get an idea of how the rate of sea level rise has changed, apart from the highly irregular month-to-month and year-to-year fluctuations, let’s smooth the data:

smooth

Notice that rapid rate of increase most recently? Notice that recent acceleration? Yep.

We don’t have to use a fancy smoothing method. We could just use 10-year moving averages:

Fremantle_10yr

Notice that acceleration around 1990? Notice that extra-high rate of increase recently? Notice that the highest 10-year average is the most recent one? Yep.

The truth is that sea level rise at Fremantle has accelerated recently. It’s currently increasing at over 6 mm/yr. The Mörner/Parker model is wrong, and their result that the current rate of sea level increase at Fremantle is a mere 1.5 mm/yr is wrong. But … that’s what they wanted to get, and you have to admire the ingenuity they applied to get it.

But wait, there’s more, the pièce de résistance! Evidently they weren’t satisfied just reducing the estimated sea level rate at Fremantle to a paltry fraction of its true value. They wanted to eliminate it entirely! And how, you wonder, could they do that?

The answer lies in their purple line, the “local subsidence factor in the order of 1.4 mm/year.” They actually claim that Fremantle is subsiding at that rate, so if we subtract subsidence of 1.4 from their low-ball estimate of 1.5, we’re left with practically nothing! Now that is ingenious.

And how, you wonder, did they get their estimate of the subsidence at Fremantle? Here’s how:

The rise from 1913 to 1956 was the order of 2.5 mm/year. Because there was a general global eustatic rise during this period of about 1.1 mm/year[23,27,31], the Fremantle tide gauge is likely to include a local subsidence factor in the order of 1.4 mm/year (purpel line).

Yes — because sea level rose at Fremantle faster than it did globally during the time period 1913 to 1956, they conclude that Fremantle is subsiding. They also claim that the sea level rise rate globally during that time period was only 1.1 mm/yr, but all three references they give to support this are papers by the same author: Nils-Axel Mörner.

If we use the global sea level reconstruction of Church & White (2011), the estimated rate from 1913 to 1956 is actually 1.4 mm/yr. More important, let’s compare the rate of change at Fremantle according to the Mörner/Parker model, to that according to the Church & White global data:

rate_comp

Notice that they used only a time period when the rate at Fremantle was higher than the global rate? Is that more “cherry-picking”? Yep.

Let’s try their own logic with a different time span: from 1956 to 1993 the rate at Fremantle is only 0.2 mm/yr but the global rate is 1.7 mm/yr. Therefore Fremantle isn’t subsiding, it’s actually lifting at a rate of 1.5 mm/yr!

If that logic seems ridiculous to you … it does to me too.

The fact is that sea level change is not globally uniform. The differences between the rate at Fremantle and the global rates are not necessarily due to subsidence (or lift!). Doesn’t Nils-Axel Mörner know this?

It seems pretty clear to me that they simply cherry-picked a time span when the sea at Fremantle was rising faster than the global average, for the specific purpose of claiming subsidence — so they could then remove their estimate from the present rate in order to make it go almost to zero. When it comes to hiding the sea level rise (and its acceleration) in Australia, Mörner and Parker have shown extraordinary care and skill.

By the way, it has been confirmed that Albert Parker is the same person as Alberto Boretti. You may recall both names from this post about comments submitted to a journal in response to a paper by Christine Shepard. There were three submissions, but only two were published. That’s because one was from Albert Parker and another from Alberto Boretti — yes, two comments submitted by the same person under two different names. Draw your own conclusion.

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78 responses to “A Möurnful Application of Care and Skill

  1. Incredible dishonesty. I can sort of understand how one person might be able to convince himself that this wasn’t fabrication. But two people? Actively discussing the data? No way.

  2. Note also the two authors ‘care and skill’ in avoiding referencing any literature on subsidence in the Perth Basin…

  3. How sad.

  4. What a sad, shabby, sordid tale.

    • Horatio Algeranon

      A tale told by a Mörner
      Full of cherry picking and subsidence
      And signifying nothing

      Stay tuned for “The Crime of the wretched Mörner”

      Water, water, every where,
      And all the lands did shrink;
      Water, water, every where,
      And just a drop in the drink.

  5. The Boretti comment on Sheppard still seems to be available (doi:10.1007/s11069-012-0160-2). Sheppard’s response to the various comments on her paper notes that Boretti’s comment is very similar to Boretti’s comment on a paper by Cooper (http://dx.doi.org/10.1016/j.ocecoaman.2012.05.031).

  6. Some readers may be interested in the Hunter & Brown comment on an earlier Boretti (Parker) paper. Amongst the various errors we found that Boretti’s dodgy fit to the data gave 78-mm of sea level rise but this was reported as 50-mm in Boretti’s paper. Does this make the games discussed above almost seem subtle? Also, Boretti plotted monthly data (sometimes with y-axes of >1 metre) and consequently significant long-term trends were hard to see.

    We wrote about this and the media coverage of Boretti (Parker) for The Conversation at http://theconversation.edu.au/peer-review-isnt-perfect-and-the-media-doesnt-always-help-11318

  7. Fantastic post. Really interesting analysis.

  8. Lars Rosenberg

    Nils-Axel Mörner’s father, Stellan Mörner, was a famous swedish surrrealist painter, about whom he has written, in a pamphlet from 1980: “My dad’s relation to his art is identical to my relation to my science.” That quote may explain some of his inventiveness.

  9. While the Morner & Parker paper is substandard, there are two GPS stations in the Fremantle area which clearly indicate significant recent subsidence. The GPS Perth station, which is nominally tied to the Fremantle tide gauge though 32km away, shows ~3mm/yr downward local land movement from 1996-2010. The nearby Hillarys tide gauge is twinned with a much closer GPS station, which roughly indicates downward land movement of 4-5mm/yr from 2006-2010 in that location.

    The Peltier ICE5G database suggests only a small negative contribution to sea level change from GIA, so what’s the cause of this apparent large vertical land motion? If these subsidence rates are mostly caused by human activity they probably aren’t going to be relevant for analysis of sea level change going back in time. However, if I adjust the Fremantle and Hillarys tide gauge trends for 1993-2012 by the vertical motion found at their GPS partners they go from 7.5mm/yr and 10mm/yr to 4.5mm/yr and 5-6mm/yr respectively, which agree better with each other and the corresponding satellite grid trend of 5.5mm/yr.

    Weirdly, Morner and Parker mention the availability of GPS data once but don’t seem to have looked at it.

    • Paul S

      Yes, there is local subsidence in and around Perth, probably due to groundwater extraction. However, the Fremantle gauge is on bedrock and shouldn’t be affected by this.

      Neil White

  10. I have already commented extensively on Morner and Parker 2013 at Skeptical Science.

    http://www.skepticalscience.com/news.php?p=2&t=88&&n=1153#93931

    On their use of Fremantle data, I say:

    “Much of Morner’s criticism of the ABSLMP is based on the idea that twenty years is far to short a time to determine long term trends. (Despite that, he purports to find a significant five year trend in the Fremantle data, showing he is nothing if not inconsistent.) However, as a criticism of the ABSLMP, this is distinctly a straw man. They have this to say on the subject (in ABSLMP 2011):

    “It is important to emphasise that as the ABSLMP sea level records increase in length, the sea level trend estimates will continue to stabilise and become more indicative of longerterm changes. Caution must be exercised in interpreting the ‘short-term’ relative sea level trends (Table 2) as they are based on short records in climate terms and are still undergoing large year-to-year changes.”

    (My emphasis)

    In essence, Morner has taken the AMSLMP’s own caution and expanded it, incompetently, into a “scientific” paper, taking care all the time to not mention the ABSLMP’s original caveate.”

    That was just the fifth point in my look at the dreadful, and dreadfully dishonest paper.

  11. Sad, shabby and sordid indeed, but it does show what lengths the anti-science crowd has to go to, in order to deceive the public about global warming. That says to me that the evidence for AGW must be extremely strong and that they are perfectly well aware of it – the extent and ubiquity of deception from the deniers shows that there really isn’t any valid argument or evidence that would support a ‘nothing to worry about’ position on global climate, otherwise we’d never hear the end of it. Literally all of the deniers’ arguments involve falsehoods of various kinds, because the real evidence tells completely the opposite story to the one they want everyone to believe.

  12. By the way: if there is some subsidence, that still makes the local tide gauges go up, and it still has meaningful local consequences. For the local people, or nature, it makes no difference what is the cause of local sea level rise. Stuff will happen.

    On the other hand, if you want to understand global sea level rise .. the tide gauges of one location don’t say all that much. As indeed there could be specific local issues. If you don’t know those from independent other measurements .. that single gauge cannot tell you much about global sea level behaviour.

    This paper seems to combine things exactly the wrong way round. That is what you might do if you’re confused yourself, or if your goal is to confuse.

  13. They apply the FUD early on:

    The least we can say is that the situation is far from conclusive and straight forward.

    And I particularly like the “Acknowledgements” para at the end of their paper.

    It doesn’t actually acknowledge anyone – but says that everyone needs to acknowledge that sea level research is controversial, and, with not a hint of irony:

    in this paper we try to avoid personal views and build up the story on straightforward analyses…

    Straightforward indeed.

  14. Horatio Algeranon

    one was from Albert Parker and another from Alberto Boretti — yes, two comments submitted by the same person under two different names

    Well, at least it’s a good thing that both Albert and Alberto have the same opinion (despite the profound difference in their first name)

    Imagine how difficult it would be if one believed sea level rise was real and one did not.

    There’s a real “dichotomy” for ya — one that would prolly require a lobotomy to fix.

    • [Unkind quips about Parker/Boretti suppressed here.]

    • I wonder who was the Parker and Boretti suggest as reviewers for their manuscripts…

    • Horatio Algeranon

      “Inseparable Twins”
      — by Horatio Algeranon

      Parker and Boretti
      Like meatballs and spaghetti
      They go together well
      Like farmer and the dell
      Abbot and Costello
      Marshmallows and jello
      Peanut butter and jelly
      Donuts and a belly
      “Skeptics” and denial
      Mendacity and guile
      Morner and his horses
      Fiddle dee-dee of courses
      Tony and his goofs
      Trzupek and his proofs
      McIntyre and McItricks
      Mathwank and statistricks
      Curry and her pause
      Why? It’s “just because”

  15. There is serious subsidence problem because of groundwater pumping in the Perth Basin and Freemantle is part of the basin. From Featherstone et al in Journal of the Royal Society of Western Australia, “Anthropogenic land subsidence in the Perth Basin:”[Depending on the time-span chosen over which linear regression is applied, different subsidence rates can be obtained. Fourteen years of data give a subsidence rate of -4.6 mm/yr, but this increases to -6.1 mm/yr during the 2000–2005 period of increased groundwater extraction] Note the acceleration coincides with the sea level rise. Also the historic Fremantle tide gauge measurements have not been corrected for land subsidence. And the study authors warning that this subsidence contaminates the tide gauge records so they are exacerbated.

    http://www.cage.curtin.edu.au/~will/Featherstone53-62.pdf

    [Response: It was already mentioned by Neil White that there is subsidence at Perth, probably due to groundwater extraction, but that the Fremantle tide gauge is on bedrock and shouldn’t be affected by this. Perhaps more telling is the fact that the Fremantle tide gauge data agree rather well with satellite altimetry of sea surface height for that location, which is totally unaffected by local land subsidence.

    I’m afraid the claim that the estimated rate and acceleration at Fremantle is due to subsidence just doesn’t “hold water.”]

    • Gonzo.
      Also page 22 of http://www.marine.csiro.au/~griffin/articles/Deng_AustralianCoasts_RevisedVersion_Figsin.pdf
      (Which I expect Neil White would know well) re-iterates the same.
      Of course South West Western Australia is a very well known “canary in the coal mine” of climate change given that several step reductions in rainfall have occurred which would exacerbate the groundwater withdrawal.
      I find it ironic that an attempt to magic away a sea level rise signal has to invoke another consequence of climate change.
      Also:check page 54 of your reference http://www.cage.curtin.edu.au/~will/Featherstone53-62.pdf
      Note the signature of groundwater withdrawal (a sharp drop from circa 1999-2007) is not reflected as a rise in the Fremantle gauge.
      Ground subsidence is adding to the problems of the west, already hit with rainfall reductions ans SLR. It is a long way from being the good news denialists are spinning it as.

      • Martin Vermeer

        > (Which I expect Neil White would know well)

        One would hope so, since he is one of the authors :-)

  16. Some of the stranger twists in the Parker / Boretti story are detailed at http://www.desmogblog.com/2013/04/28/ufos-sea-level-rise-and-magnetism-climate-science-denial

  17. I keep coming back to the thought that actual science would be easier to write than this twisted denial nonsense.

  18. David B. Benson

    I am an amateur geologist of 53 years standing. Other than ground water withdrawals, no part of Australia shows anything but the slowest rates of vertical geological motion. Well, river estuaries might show a bit more as silt is deposited.

  19. I’m glad to see you’ve begun to expose the lies in the Mörner & Boretti-Parker “paper”. There’s far more crap in there than just the rubbish about Fremantle. Incidentally, there’s corroborative evidence that Fremantle isn’t subject to any great degree of subsidence (Hillarys to the north is), because I’ve analysed all the gauges which M&B-P claim to have analysed (they didn’t, it’s obvious to me), and confirmed that Fremantle fits into an escalating series of rates from Bunbury to Darwin, confirmed by satellite data, Hillarys excepted,it’s “out-of-sequence”, and much higher.

    While on the subject of Fremantle, they say
    “Confining the rate analysis to the last 10-20 years, as the Australian governmental offices have done, would have given meaningless rates in the order of 6.0-6.5 mm/year (Figure 2a) in line with the 20-years SEAFRAME mean record of 5.4 mm/year.”

    “Would have given” means of course “if we’d done so”, yet they say they analysed all stations from 1990-2010, and the “6.0-6.5″ (a guess, actually it’s 5.27 1990-2010) alone shows their statement “no fitting produces a sea level rise in excess of 1.5 mm/year” is garbage.

    I’ve emailed the journal with charts, links to satellite and other data, published papers, and a long list of contradictions and disconnects in the “paper”, and requested that it be withdrawn. The journal asks authors to provide a list of 5 reviewers. I’ve asked them to provide me with just the names on that list; it might be very informative.

  20. Tamino said:
    !”The fact is that sea level change is not globally uniform. The differences between the rate at Fremantle and the global rates are not necessarily due to subsidence (or lift!). Doesn’t Nils-Axel Mörner know this?”

    Yes he does, perfectly well, when it suits his argument-of-the-moment. The 1.1 mm/year he claims was the global rate, he says he calculated from the rates at Amsterdam & Stockholm, somehow getting an “isostatic” (true rate) rate for the whole of Europe from those 2 gauges.. The Amsterdam record ceased in 1925, and had an unknown rate of subsidence. Stockholm has been rising at a rate of about 5 mm/year (post-glacial rebound), so shows a negative rate of sea-level change throughout its record.

    If anyone can figure out exactly how he did it, they’ll go down in history – what he says he did is impossible.

  21. The Morner & Parker paper is published in a “Trade Science Inc” journal. This publisher is on Beall’s list of predatory OA publishers (http://scholarlyoa.com/publishers/).

  22. I’ve had half a dozen enjoyable visits to Perth and environs.
    Is saltwater intrusion becoming a problem, or does the geology lessen that?

  23. John,
    Tree death started in about 2009 or 2010 along the banks of the Swan River near Burswood and along the river near Como. These trees were Eucalypts, Casuarinas, and ‘Tea Trees’. My guess is that it is due to salt water intrusion as the trees lie in low parts of the bank that are now regularly inundated at high tides.

  24. Oh and you can see where the dead trees are in Google Earth; riverside of the Burswood golf course, on the opposite bank in front of Trinity College, and along the riverside of the Kwinana Freeway in Como.

    Global Warming has hit Perth hard. Reduced rainfall has rendered every dam in the hills useless as they contain less than 20% water – which is too low to use due to higher salinity and turbidity. Also have big drawdown in our aquifers – so much so that the government has taken the drastic step of looking to water recycling (I know this is actuallt obvious, but given our Government are conservative denialists in WA, it’s a clear sign they have finally noticed there is a problem).

  25. There has been an increase in groundwater extraction in Perth in recent times to make up for reduced rainfall and increased demand. It is being monitored by (e.g.) coastal bores to check for saltwater intrusion into the water table, so saltwater intrusion is unlikely to be a problem in the near future. There is also a desalination plan at Kwinana (SW of Perth). There was a move a few years ago to start tapping the Yarragadee aquifer (sort-of in the Margaret River area) to help meet Perth’s needs. That was stopped. I don’t know how they are going to work around that.

    Going back to the start of this thread I looked at the Morner and Parker paper that Tamino linked to. It is not possible to produce the garbage results that they come up with by any remotely competent analysis of the data, as has been stated in comments above. Their figure 2 is wrong and it is a lift from a paper they (it may have been Morner and Boretti then) submitted to Nature Climate Change a year or so ago. This paper was firmly rejected, and they were even shown by one of the reviewers how to draw the correct version of that graph (complete with corrected version).

    Morner has in the past produced hand-drawn sea level graphs (e.g. in his paper on the Maldives from 2004) that bear no relationship to the data that he quotes in support. That paper was trounced by four peer-reviewed papers, one of which (by a geologist) referred to the “unconstrained by data” nature of some of his “results”. The production of results that bear no relation to the data they are supposedly based on continues.

    Neil

  26. “unconstrained by data” — LOL

  27. Neil

    The tree death along the Swan River is likely to be salinity as the river is an estuary, so is already salty around Perth and these trees are in areas now regularly inundated during high tides and storms.

    As is always the case, the effects vary from place to place. Drawdown in Perth Aquifers has reached the point where it is obvious we can’t sustain what we have let alone the expected future population.

    The Southern Yarragadee was stopped for environmental concerns as it feeds the Blackwood river near Nannup.

    Interestingly, The Yarragadee, which could serve Perth for a while with water is actually absent under Perth and Fremantle. The Formation must have been eroded out prior to deposition of the Kings Park Shale.

  28. Nathan & Neil: thanks.
    I looked on GoogleEarth, those areas seem about 10km upstream from Freemantle. Ugh.

  29. I cycle around a chunk of the Swan River regularly. There has been a steady loss of trees along one particular stretch, as a few get blown over every time we have a storm. I think this is because the slightly higher river level has lessened their roots hold on the ground.

    The river wall along the stretch frm the city to the University of Western Australia was rebuilt recently, and quite sensibly they made it higher (but nobody said anything about global warming). It is a tidal river, and will rise with the sea level.

  30. I think Perth is a good example of an effect that people often forget when talking about Sea Level Rise, not just the salt water incursion issue.
    People seem to talk about armoring the shore better, but don’t seem to think so much about the more widespread effects on cities with substantial rivers running right through them, which many coastal cities have.
    Given the configuration of the Swan, I suppose they could build a dam at the mouth and pump.
    BTW, !15 years ago, we had a wonderful wine tour on the Swan,in canoes, as many wineries had boat docks.

  31. [ However, the Fremantle gauge is on bedrock and shouldn’t be affected by this.] With all due respect to Neil White I would disagree that the tide gauge is on bedrock. [edit]

    [Response: I’m gonna guess that Neil White (one of the world’s leading sea level experts) knows better than you.

    This is not a forum for propaganda, or for obstinate clinging to unreasonable doubt, you sad, sad man.]

  32. I have a rather unrelated question. All the skeptics are talking about ‘no warming’ since 1998. But as I understand it 2010 and 2005 were both warmer than 1998 so there has been recent warming. Is this correct? If not, could someone explain this to me. Thanks.

    [Response: Yes, 2005 and 2010 were warmer than 1998. But we all know there are year-to-year fluctuations (2011 wasn’t as warm as 2010) so the simple fact that one year is warmer than another doesn’t tell us a whole lot.

    What they’re talking about is the trend. It’s usually estimated by linear regression, which not only estimates the trend itself (rising or falling, and by how much) but the uncertainty in our estimate. Given an estimate of the trend and its uncertainty we compute a “95% confidence interval” — a range in which the actual trend is 95% likely to be.

    If that confidence interval includes zero, then there’s a realistic possibility — statistically speaking — that the actual trend is zero. That’s the case for data since 1998.

    But there’s also a realistic possibility that the trend is anywhere within the confidence interval. For short time spans (and for global temperature data, “since 1998″ is short) that includes a lot of possibilities, including continued warming at the same rate as prior to 1998. From just a statistical analysis, we can’t tell. Notice that a lot of those claims of “no warming” will include the phrase “no statistically significant warming” — that’s what they’re referring to.

    Suppose for instance we computed the trend since last Friday, and that temperate had gone down (a wee bit) so the trend estimate is negative. But the uncertainty is so huge we can’t really nail down the trend with sufficient precision to know whether it’s going down or up. Such a trend estimate is, essentially, meaningless.

    You can *always* find a short enough time span to declare “no statistically significant warming since XXXX! One usually does so by deliberately choosing a starting point near a time when temperature was unusually high due to random fluctuation. It turns out that in 1998, temperature was unusually high due to random fluctuation. That’s why they choose 1998 (sometimes 1997, also very near that time). The starting time isn’t chosen for any valid physical reason, it’s chosen because it gives them the result they want (“no statistically significant warming”).

    Choosing which data you use because of the result it gives is called “cherry picking.” Statistically speaking it’s cheating.]

    • FWIW, some deniers–“skeptic” is not an accurate label–also ‘cherry-pick’ data sets in connection with this claim. Usually the UAH satellite data for the lower troposphere is preferred. In that case, their claim gains in what I would term ‘apparent plausibility’, since in that data set 1998 remains warmest year to date. (It’s also, I believe, a more variable data set, which would affect the calculations of statistical significance.)

      In confronting this claim, I like to point out that just a few years ago it was fashionable to claim that there was ‘no (statistically significant) warming since 1995.’

      See, for example:

      http://www.dailymail.co.uk/news/article-1250872/Climategate-U-turn-Astonishment-scientist-centre-global-warming-email-row-admits-data-organised.html

      It was correct then, technically, though it was just as much of a cherry-pick as is the current version of this meme. But since 2010, despite the ‘lack of warming’, the trend from ’95 forward has in fact attained statistical significance.

      There’s no good reason to think that the same won’t be true for ’98 in turn–though it may take a bit longer, as it really was a monster El Nino that year.

      • Actually, it looks like the estimated trends in the surface temperature since the beginning of 1995 have currently moved below the 95%-significance threshold again (see http://www.skepticalscience.com/trend.php), after they had exceeded it for the period 1995.0 to 2011.0 in the HadCRUT4 data set. The trend still exceeds the 90% threshold, though, like it already had done at the time when Phil Jones gave his interview to the BBC.

        If one talks about statistical significance one always should also provide the information to what probability the statement about statistical significance refers. AGW-deniers like to make the assertion that the trend wasn’t statistically significant, and, therefore, there was “no global warming”, even if the trend only fails the test for a 95% significance threshold, but passes the test for a lower thresholds, e.g. 90%. Monckton, for instance, uses this false reasoning for his propaganda. A successful rejection of the Null-hypothesis that the trend was Zero for a lower significance threshold still allows the conclusion that a trend was present in the data, only the probability to have erroneously rejected the Null-hypothesis increases with a lower threshold.

        [Response: More important, start times from 1995 to 1998 are chosen because they yield a given result. This alters the statistics — dramatically.]

      • What start years are preferably chosen for the cherry pick can be quite well predicted just by looking at any ENSO index. For instance 1997/98 because of the very strong El Nino. 1999 and 2000 are rather omitted. These were La Nina years. Some have already started the usage of the year 2002 for claims of alleged “global cooling” (already publicly endorsed by Judith Curry). I suspect, at the end of this decade they will use the El Nino year 2010, but not 2011 or 2012, because these were La Nina years again.

      • Thanks for that update, Jan.

  33. Great. Thanks a lot. This clears things up for me.

  34. Well I contacted Freemantle Ports which run (along with Landgate and Curtain University) the tide gauge and they are aware of subsidence issues. And to their knowledge NO subsidence studies have been done. Considering the Geo studies of the area and without any supporting evidence from Neil White or others concerning the integrity/calibration of the Freemantle tide gauge the data has a fair amount of uncertainty.
    Cheers.

    [Response: On the contrary, the paper you linked to yourself estimated this:

    The results from this particular repeat GPS survey
    were inconclusive because, even using five to seven days
    of measurements, the GPS-determined ellipsoidal height
    near the Fremantle tide-gauge was determined, after
    height corrections for the different benchmarks, to be
    exactly the same in 2010 as it was in 1999. Assuming
    independence and the general law of propagation of the
    variances of each ellipsoidal height estimate at each time-
    epoch, the ‘subsidence’ over this period was (0±6) mm/
    yr. Within one-sigma error bounds, this is statistically
    consistent with the ~-5 mm/yr rate determined from the
    continuous GPS station at Gnangara (described next). Of
    course, there is also the possibility that the Fremantle
    tide-gauge is not subsiding or not at the same rate as
    Gnangara.

    Note that their estimate of the subsidence at the Fremantle tide gauge is zero — although the uncertainty makes that estimate “statistically consistent with the ~-5 mm/yr rate determined from the continuous GPS station at Gnangara.”

    It seems to me that the good agreement between Fremantle tide gauge data and satellite altimetry rules out “the ~-5 mm/yr rate determined from the continuous GPS station at Gnangara.” In addition, the acceleration observed at Fremantle agrees with the results of the SEAFRAME data from the Australian Baseline Sea Level Monitoring Program. Those instruments record GPS data so that subsidence can be measured and corrected for.

    It also seems to me that you’ll dig just deep enough to find cause for doubt, because you’re more interested in justifying doubt than in discovering what the available data reveal.]

    • Michael Sweet

      There is also the point that Neil White is an acknowledged world tidal expert who lives in Australia. He is likely to have private knowledge about the Fremantle gauge. Gonzo would get much more reliable data by writing to Dr. White than by contacting Fremantle Ports, whose primary purpose is not monitoring tides.

  35. You did leave out the last sentence in that paragraph. “Of course there is also the possibility that the Freemantle tide-gauge is not subsiding OR not at the same rate Gnangara” Hardly certain.

    [Response: I quoted it in full, including the last sentence.

    Since it seems you won’t be satisfied with anything less than absolute proof, I suggest you stick to mathematical theorems and vodka.]

  36. A little subsidence may be helpful to the cause of dowsing for doubt, but too much seems to imply that sea level rise is actually worse, if one is left with a significant SLR residual after accounting for and depending on subsidence.

    “Be careful what you wish for.”

  37. Paul, Tamino… I looked at Paul’s page on regression, and I didn’t see something I was expecting, which was an estimate of the ‘noise’ to be used to determine the sample size to see a signal of x% of the noise. Another way to put this is I can make the noise of the 30 sample set arbitrarily large, and the significance of a 30 sample test will go to zero.

    I simply don’t recall how to do this calculation, and it’s not obvious either in the stats package that I have available. (Prostat )

  38. Gonzo

    You said earlier: “With all due respect to Neil White I would disagree that the tide gauge is on bedrock.”

    Why do you “disagree that the tide gauge is on bedrock”?

    Neil

    PS The name of the place is “Fremantle”, not “Freemantle”.

  39. I submitted some info in my first post that didn’t make it past moderation. All well and good it’s Tamino’s blog. A Geo study on coastal erosion shows the limestone bedrock to be quite deep in that area as much as 28mtrs below sea level in the Rockingham/Becher Plain. And the make up of the soil under the tide gauge to be clay and peat.

    http://www.ga.gov.au/image_cache/GA6535.pdf

    • The document you link makes no specific claim about the substrates under the tide gauge…it’s your inference,Gonzo…and the areas with a history of varying subsidence under water extraction are sands distant to the west and north-west of the broad outcropping limestone along the coast. Ok?

  40. Gonzo.The Tamala Limestone outcrops around Fremantle city, so it is close to the surface there. It supports the ridges around Fremantle, If you look in google Earth you should be able to see them. The river is an Estuary, so the peat and clay could be from flood events, but should be supported by the Tamala Limestone.

    lots of work has been done on recent sea level changes by Philip Playford of the Geological Survey of WA, you’ll find good 50,000 scale geology maps on the GSWA website too.

    Although Playford is good friends with Ian Plimer… So… Hmmmm

  41. This shows the location of the Tide Gauge, I believe

    http://www.psmsl.org/data/obtaining/stations/111.php

    So it’s on a pier.

    Would be concrete beneath… in calcareous sand… On top of Tamala Limestone.

    • Nathan

      Some of the positions that the PSMSL use have been rounded in the past and are not as accurate as they might seem. I understand that the historical record is from a gauge more-or-less at the river mouth on the south side of the river. That makes no difference for this discussion. Thanks for the detail on the geology! Also, I think the Fremantle readings are now being taken from another site nearby. This could be the one the PSMSL site points to, but I thought it was a little way up river. Again, as I understand it, this makes minimal difference.

      The difference in rate between the Fremantle gauge (on bedrock) and the Hillarys gauge on a less stable site further north, and more-or-less due west of the PERT GPS site (I think this GPS site is being referred to as Gnangara (spelling?) here) of ~3 mm/year is, according to a land hydrologist from Perth that I talked to a couple of years ago, right on the edge of plausibility (or more likely beyond it) for the amount of groundwater being withdrawn and the Perth basin geology. So trying to spin the increase in the rate of sea-level rise at Fremantle as being due to groundwater extraction is pointless. Groundwater extraction is an (almost) plausible explanation for the difference for the difference between Fremantle and Hillarys. But that is all.

      Neil

      • There has been a lot of work on the compression of Perth Aquifers. Some places around Perth (fairly distant from Fremantle) like Stirling, Gwelup, and around Gnangara have all started sinking as the aquifers deplete. Bad sign as that is then lost storage for the aquifer…

  42. @Nick, from the study “There is a clear distinction between the estimates of top limestone on the Rockingham/Becher Plain, which are almost without exception below sea level, relative to the estimates directly to the east, in the vicinity of the Kwinana Town Centre, which are predominantly above sea level. The SCPT that was undertaken in this area (Figure 7.14) also suggests the top of the limestone is well below sea level. The SCPT penetrated 33.05 m before terminating, and the height of the ground surface at this point is approximately 5 m, as estimated from a DEM. Therefore the top of the limestone is at or below approximately 28 m below sea level at this point. The estimate of top limestone at the nearest microtremor point (to the east) is -26.6 m AHD, which is further evidence of the robustness of reconstructing the upper limestone surface with microtremor measurements” It’s seems pretty clear the soil at the harbor/river entrance where the tide gauges are located are not directly on bedrock limestone. (unless the gauge is up river where the limestone IS above ground)

    I don’t believe the sea levels aren’t rising there I just think there are more/may be other factors in play at the historical gauge site which should be taken into consideration.

  43. Gonzo, get a map and check the locations of these places relative to Fremantle (or Freo as we call it here). Kwinana is a fair distance south.
    There is limestone outcropping near the bridge that crosses the Swan River in Fremantle and all along the ridge there.
    We probably all agree there is material under the tide gauge that is not limestone, but this material would rest on the limestone. A few metres of mud/clay and sand will not compress so much when it is supported by limestone underneath… Why would it compress? There is not much in the way of sediment load from the river, the movement of the Swan is pretty light.

  44. Michael Sweet

    Gonzo,
    A quick GOOGLE shows that Kwinana is 10 miles from the Fremantle tide gauge, hardly a comparable point. Arguing with Neil White, who is responsible for tide gauges in Australia as his work, you are required to provide direct evidence. Relating to a drill 10 miles away is not sufficient. Everyone knows that bedrock varies from location to location, even over distances of a hundred meters. You must provide contrary data about this specific gauge. Think it through: they put a GPS on Gnangara but not at Fremantle (the much bigger city) Why? Because they knew the gauge at Fremantle is stable.

    You are presenting a perfect example of a denier who will not accept data because you do not like what it shows.

    • Michael

      Thanks for the promotion, but I do not have any responsibility for running Australian tide gauges. That is done by the National Tidal Centre (NTC – http://www.bom.gov.au/oceanography/projects/ntc/ntc.shtml) which is part of the Australian Bureau of Meteorology, and the various port authorities, who send their data to the NTC. NTC has the responsibility of managing and distributing Australian tide gauge data and, as part of this, send data to the PSMSL archive.

      Neil

  45. Peter Prewett

    Interesting comment on sea level rise ‘Global Sea Level Rise Dampened by Australia Floods’ at:-

    http://www.sciencedaily.com/releases/2013/08/130819141610.htm

  46. Nathan the Rockingham/Becher Plain is part of the Quindalup Dune System which is part of the bigger Swan Coastal Plain. And the whole region has subsidence issues not just from groundwater extraction. From an WA EPA Geo study,” The Perth Basin has been subsiding along the Darling Fault (approximately marked today by the Darling Scarp) for at least 200 million years accumulating over 5000m of sedimentary material.”

    According to GLOSS the historic gauge is only a back up (Neil White mentioned that above) to the PSMSL site just south at these coordinates
    (-32.065556 ,115.748139). I suggest the street view which shows the sandy soil clearly. Even if they bored down deep as they do for pier footings
    they area is susceptible to movement. A simple GPS survey would put this
    to rest.

    Cheers.

    http://www.epa.wa.gov.au/docs/1359/App41359/VCSRG-DECOctober2009ReportGeologyofSCPDawesvilletoB.pdf

    [Response: And you yourself linked to a GPS study which estimated the rate of subsidence as zero. Furthermore, the agreement between the Fremantle tide gauge data and both satellite data, and data from nearby ABSLMP stations (which include GPS data) pretty much proves that the rate of increase, and the recent acceleration, in the Fremantle tide gauge data is due to sea level change. The simple fact is that the amount of subsidence you suggest is plainly impossible — you just won’t face the fact that there is no “issue” to put to rest.

    But you persist. Is your harping about any uncertainty you can find regarding subsidence at Fremantle a brilliant propaganda move? It draws attention away from the real subject of this post, which is the grossly incompetent and misleading interpretation/analysis of Morner and Parker. Do they owe you a fan letter?]

    • Gonzo.
      Oh dear. This is so sad. You are not even clutching at grains of sand here. Did it occur to you when you hit that apparent ‘pay dirt’ pointing to 5,000m subsidence over a period of over 200 million years to actually pause and consider how such a rate would appear in comparison to the rates of modern SLR? Did the appearance of the word “subsiding” blind you to all else? Or will you next be trying it on by pointing to the sentence following your quote as evidence of accelerating subsidence?
      Whichever, thank you. I enjoy a good laugh.

    • Gonzo

      I don’t doubt that there is long-term subsidence in this area. What rate is the land subsiding at? Whatever it is it is almost certainly swamped by the land uplift through GIA (Glacial Isostatic Adjustment – someone mentioned GIA above). But this is all irrelevant anyway, because these longer term (tens of thousands to millions of years) won’t cause a sudden increase in rate over the last few decades. Or are you proposing that the Perth Basin has suddenly started subsiding faster?

      Do you have any comments on the actual subject of this thread?

      Neil

      PS I’m no geologist, but a quick bit of arithmetic on the numbers you give (5,000,000 millimetres over 200,000,000 years suggest a negligible rate – much smaller than the uplift (relative to the ocean surface) from GIA. Perhaps a geologist can help us out and interpret these numbers properly.

  47. This should help focus the mind of any climate science deniers with coastal property.

    http://www.bloomberg.com/news/2013-08-19/greenwich-stilt-houses-foreshadow-impact-of-new-fema-maps.html

  48. Philippe Chantreau

    5000 divided by 200 million. Good one Gonzo…

  49. Gonzo… I am a working hydrogeologist, living in Perth. So I can tell you that the ‘facts’ you keep bringing up are either irrelevant or wrong.
    Yes the Perth Basin has been the site for subsidence over geological time, the lowest formations are from the Carboniferous-Early Permian and so would be over 300 Million years old. The Perth Basin under Perth is about 14,000m deep and is bounded to the east by the Darling Fault. However there has been no movement on the fault since the Cretaceous and there is just isostatic adjustment (as material is weathered off the continent lifts and as material is deposited on top it sinks slightly with no net loss or gain).
    Interestingly this paper by Mike Sandiford outlines the uplift in the southwest of Australia following the collision with Indonesia. This uplift is ongoing and is one cause of the loss of stream-flow in the inland rivers of Western Australia.

    http://www.sciencedirect.com/science/article/pii/S0037073807003016#bib81

    I suggested you looked at the work by Phil Playford on sea level changes in the recent past around Perth, but it seems you couldn’t be bothered. Maybe go to the website of the Geological Survey of Western Australia and look for a book on Rottnest by Phillip Playford. It shows the sea level changes over the few last thousand years.