A Few Other Stations

Mr. Wakefield doesn’t seem to like the tide gauge data from Boston, since it so easily shows how wrong he was about “NO acceleration.” He wants me to “do a few other stations, like in Australia and Brest, France.

Let’s start with Brest, France. Here’s the data (with the seasonal signal removed):

Let’s smooth the data, to get a better idea of what the trend is doing:

Hmmm… both acceleration and deceleration, with acceleration recently. Does that sound familiar? I won’t bore regular readers with yet another exposition on its statistical significance; I doubt Mr. Wakefield would believe it anyway.

Lest he object to my using some fancy-schmancy “college boy” mathematical smoothing method, let’s use something as simple as it gets: moving averages:

Just in case it’s a little difficult to see on that scale, let’s plot just the moving averages:

Hmmm… both acceleration and deceleration, with acceleration recently. Does that ring any bells?

We can’t neglect Australia. Its longest tide gauge record is from Fremantle:

Hmmm… both acceleration and deceleration, with acceleration recently. Does that sound familiar?

The next-longest is Sydney, Fort Denison (2). We could combine it with Sydney, Fort Denison (1), but it won’t make any difference. This station may well have “issues” related to groundwater extraction, but hey, let’s do it anyway:

Hmmm… both acceleration and deceleration, with acceleration recently. What a concept.

Maybe just two stations from Australia isn’t enough. Let’s take all these stations:

We’ll combine them to form a pan-Australian composite. And what do we get? This:

Hmmm… both acceleration and deceleration, with acceleration recently. Imagine that.

And now a message for Mr. Wakefield. It’s time for you to face this issue (the one that you brought up) rather than change the subject to avoid it. For the time being, confine your comments to this post only, and stay on topic: the existence of acceleration (and deceleration to boot) in tide gauge records, particularly from Australia and Brest, France. Are you able to stay on topic? If you simply admit you were wrong, we’ll set this issue aside. If not, let’s see some evidence. Put up or shut up.

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56 responses to “A Few Other Stations

  1. J. Richard Wakefield

    From Tide & Currents.

    Fort Denison:



    Not even NOAA draws an acceleration line through those points, just a nice straight line. [Response: Nor do they attempt to find, or rule out, departure from nonlinearity, they just want to show the linear trend whether the actual trend is linear or not. How many times do I have to tell you before you get it?] I dont know where you get your data from, but Tide and Currents seems to be different than what you have. [Response: I get my data from the permanent service for mean sea level (PSMSL). I didn’t bother to combine Sydney/Fort Denison 1 and 2, but other than that if you think it looks different, it’s because the plots you link to are on a very different scale, as I outlined here. Also, the PSMSL data aren’t always as up-to-date as NOAA data. Before you *insist* on the latest year, some advice: be careful what you wish for.]

    Have you seen this:

    “The absence of acceleration in the naïve averaging of the tide gauges in
    the network and every local tide gauge indicate these rates are stable.”

    [Response: First you link to more graphs, plotted in a way which obscures acceleration and deceleration as I emphasized here. Why bother when I already graphed them for this post? Because the only “evidence” you have is to look at a graph and say “See!” when the same graph on a different scale suggests otherwise. That’s not evidence, it’s repeating the same already-debunked argument. Endless repetition doesn’t make it true.

    Then you link to a paper by Parker & Ollier. I guess you missed my post showing that they have bungled some very simple math. You also seem to be unaware of Parker’s habit of just making up stuff.

    Real evidence: put up or shut up.]

    • J. Richard Wakefield

      Guess we are going to have to wait, say 10 years? When there is no acceleration showing, then what?

      [Response: I wanted real evidence, put up or shut up. You do neither.

      And just to remind you (again), the topic is acceleration in tide gauge data, not what happens in the next 10 years. I show it, you refuse to believe, then you come up with this. Weak.]

    • I dont know where you get your data from, but Tide and Currents seems to be different than what you have.
      Before one makes assertions like that, one could go to the Tide and Currents page, download the data as a csv, open it in Excel and overlay it onto Tamino’s plot with proper scaling. That way one could assess, wether or not there are material differences between the data sets. Here’s what one would get for Fort Denison:

      Blue is T&C data, gray is Tamino’s PSMSL data.

      Or one could simply post the link, write “I do not know where you get your data from” – a phrasing implying that Tamino’s data is inferior and/or fake – and leave it at that, in best pseudo-skeptic fashion.

      • About the Sydney Harbor SLH measurements, there’s a simple data transformation that one can apply to expose the natural variability clearly. The transformation essentially takes a 2-year differencing between every point on the time series, from 1900 to present. What this reveals is the ENSO signal, as described in this post:

        Why this 2-year differencing is important likely arises from a biennial modulation in the Pacific ocean cycle that has been much discussed, and also appears in climate models.
        K. B. Karnauskas, R. Murtugudde, and A. J. Busalacchi, “The effect of the Galápagos Islands on ENSO in forced ocean and hybrid coupled models,” Journal of Physical Oceanography, vol. 38, no. 11, pp. 2519–2534, 2008

        The intuitive explanation for a biennial cycle is that there is a metastable buildup in in terms of a oceanic volume imbalance over the course of a year, and that is then released the following year. It’s truly metastable in that there is nothing that prevents the biennial cycle from starting on an even vs odd-numbered year, and it could skip a beat at any time. But all the evidence points to it following a strict cycle.

        The 2-year differencing essentially removes this obscured 2-year cycle and exposes the strong ENSO cycle. The two behaviors essentially obscure one another and removing the one highlights the other. I have to admit that I only discovered this pattern after doing machine learning experiments using a symbolic regression tool. The ML tried various differencing intervals and settled on 2 years as optimal.

        BTW, the 2-year differencing also acts as a low-pass filter that removes much of the high-frequency noise from the SLH data, which is why the result is smoother.

    • “I dont know where you get your data from, but Tide and Currents seems to be different than what you have.”

      If you download and plot the data (there are links right there to do so) you can see that they are exactly the same. This is the basest request that anyone can make of you—that you could make of yourself—and that you didn’t do even this before levying such an insipid claim is telling. The two sources contain some differences insofar as temporal extent is concerned (i.e. the Fort Denison data you link to goes back earlier than 1920 (is this the difference between Fort Denison 1 and Fort Denison 2?), and also does not go past 2010), but that is it.

    • Click over to the “Variation of 50 year variation sea level trends” tab on those graphs, and you’ll see NOAA’s indications of the same deceleration/acceleration patterns Tamino is talking about. There exists some systemic, long-term, spatially global pattern in the sea level data that isn’t fully explained with a linear trend or no-change model.

    • Yet another willfully ignorant soul with a seemingly incurable case of Dunning-Kruger self-destructs. Yawn.

      And no, Mr Wakefield, that is not an example of ad hominem. Ad hominem takes the form “you are stupid, therefore your argument is wrong and can be dismissed.” In the present case Mr. Wakefield’s arguments have repeatedly been demonstrated to be wrong, yet he continues to cling to them. That he does so does not mean that he is stupid, it means that he is stubbornly engaging in stupid behavior. Fortunately there is a simple solution to that predicament: admit that you are wrong, learn from your error, and move on. There is no shame in that course, only gained knowledge.

  2. I also recommend you read this. There are HUGE uncertainties in the data, specifically from the sats. Read the conclusion.

    “In addition, the amplitude of the residual trend pattern is significantly lower than the expected error in trend patterns from satellite altimetry (in the order of 2 mm/yr to 3 mm/yr) and therefore suggests that satellite altimetry measurement is still not accurate enough to detect the anthropogenic signal in the 20 year tropical Pacific sea level trends. ”


    I would take these guys word over your attempts to find acceleration when one cannot be found.

    [Response: Clearly you have trouble staying on topic. Which is: the existence of acceleration (and deceleration to boot) in *tide gauge records*, particularly from Australia and Brest, France. But you pulled a quote out of context, from a 313-page doctoral thesis, about satellite data for the tropical pacific. We can deal with that later — after you either admit you’re wrong, or provide some real evidence that’s *on topic*.]

    • J. Richard Wakefield

      The topic is if there is, or is not, acceleration. Deal with the content of that paper. Seems they have access to the raw data, and came to the conclusion that sat data is too rot with error and noise to come to any conclusion. You reject it because you dont like their conclusion, hardly scientific.

      [Response: I made the issue clear — acceleration in tide gauge data — in the original post. You brought it up, you’re even the one who wanted me to look at “a few other stations.” But now you can’t deal with it, so you change to another subject. Are you too dishonest to own your own claims?

      We’ll deal with other subjects when you face this one.]

      • J. Richard Wakefield,
        You say we should ” Deal with the content of that paper.” This is a good idea.
        You link to Palanisamy (2016) ‘Present day sea level: global and regional variations’ which is not a short document and it comprises more than one paper. To assert from a single quote from such a long document that “I would take these guys word over your attempts to find acceleration when one cannot be found.” suggests you are not attempting to present “the content of that paper” but rather are winding up the windmills of Ontario again. To suggest you present “the conclusion” of this ‘paper’ certainly implies an Ontarion wind up.
        If you are serious, try to act serious and not like a purile pillock.

        A quiz – can anybody spot a single comment amongst the very many posted by J. Richard Wakefield that does not suggest the “guy” is but a purile pillock?

      • The topic of this article is if there is, or is not, acceleration in the tide gauge records from Brest and Australia. Not in some random paper you found just now (well, yesterday, but still).

        What’s your problem with Tamino’s analysis of this data apart from not fitting a linear model? Should he have used a different time frame? Should he have used a different model? Why?

        FWIW, I downloaded the data from the T&C 680-140 link (Denison 1&2) and plotted it in R along with a loess fit. My result looks a lot like Tamino’s, and I’m a total doorknob when it comes to this stuff. I’m a code monkey, not a statistician, and I don’t know time series analysis from a hole in the ground. But I can at least replicate the steps Tamino took to see he’s not making this up out of whole cloth. If you fit a non-linear model, you see changes in the rate of sea level rise, first down then up.

        Why is that analysis wrong? Why should he not use a non-linear model?

  3. Finally, this is a must read:

    Secular and Current Sea Rise: Level (1.6 mm / year) or SAT altimeter (3.2 mm / year) – WHAT is correct?

    Again, I’ll take his word over yours.

    [Response: Turns out I don’t speak German. In case you missed it, this is an English-speaking blog. Is this one of your tactics to create more doubt? That is, after all, your product.

    And we already figured out you won’t take my word for anything.

    How about some actual evidence, in English? We’re still waiting.]


      The link is a German “skeptic” blog. It’s like referring to WUWT for “proof” (yes, with the advantage of being in German for less understanding). If it points to real data, Wakefield should skip the blog altogether and point to the real stuff, preferably articulating his own argument instead of just saying “you must read this”.

      • J. Richard Wakefield

        Shoot the messenger much? The guy is an EXPERT. How about you deal with his argument.

      • “The guy is an EXPERT”

        Klaus-Ekart Puls has a Diploma of Meteorology. It’s been claimed he is a “physicist” by at least one skeptic site, but I was unable to verify that. He has no peer-reviewed papers that I could find.

        On the German blog Wakefield links Puls compares two different estimates of sea level trends. But he is comparing a 9-year trend (gravimetric sea level 2002-2011) with a 20-year trend (altimeter sea level 1993-2014-ish). A proper comparison (posted below) produces quite a different altimetric trend rate when the periods are matched.

        His ‘analysis’ is not remotely expert. If he does have the requisite knowledge, he’s being deceitful by not matching time periods.

        There is no reference in the bibliography to the GRACE study on sea-level change. But there are quite a few blog pages listed there. So expert.

        There is some information on the institute hosting the blog site Puls’ article appears in, which consists of retired or deceased “leading scientists,” and a post office address.

        “EIKE… is not a research institute and does not publish in scientific journals . The association is not considered by the professional world as a serious institution , but as a… politically active lobby organization….

        Purpose: Networking and public relations work of climate skeptics”

        Wakefield’s off into the Gish Gallop now. When the opposition keep moving the goalposts and ignoring the score, it’s time to quit the game.

      • Since when is Klaus-eckart Puls an expert in sea level rise? He’s got an undergraduate degree in meteorology and two scientific publications on some pollen and the way it is transported in the air, published almost 30 years ago. That’s it.

      • Shoot the messenger much? The guy is an EXPERT. How about you deal with his argument.

        As far as I can tell from searching via google and google-scholar that blog post is his only foray into mean sea level rise to be found on the net. Apart from that, he is a (retired?) meteorologist and spokesperson for EIKE, the German cousin of WUWT. Neither makes him an obvious expert for sea level related science. Please explain, why you consider Klaus-Eckart Puls an EXPERT. You may point to German sources, if need be, I’m a native speaker.

      • @Marco
        Puls is listed as “Dipl. – Metereologe”, i.e. he has earned a German “Diplom”, which is equivalent to having earned both the US bachelor and master degree.

    • J. Richard Wakefield

      Google translated it automatically. You dont have auto-translate?

      • What makes you think he’s an expert? His article hardly comes across as such. He uses the conclusion of the North Carolina legislature as a reference, has “conclusions” not supported by the data or quotes he cites and then dishes out this curious statement:

        “How can the secular “linear trend ” (cf. w) analyzed in the publication have an acceleration?

        This is a contradiction in itself. A linear trend is described by a regression line, so we can not have an acceleration!”

        He does the same incorrect thing that you seem to have done, taking the presence of a plot showing a linear trend as evidence that there isn’t acceleration.

      • Since you’re able to use auto-translate – here’s a nice report from an EIKE conference – “Report From The Epicenter of Doubt”


        Turns out the guys were openly contradicting each other, which didn’t concern the audience in the slightest.

        It’s hilarious, trust me – it’s worth the translation… :))

      • [edit]

        Response: I already told you to stay on topic.]

    • Yes, the longer-term (say, 100 years) linear trend is around 1.6mm/year. The recent trend (last 25 years or so) is more than 3 mm/year. The satellites and the tide gauges agree on this (see, for example the figure at the bottom of https://www.cmar.csiro.au/sealevel/).

      There is no actual problem here. When (as is happening) the rate of sea-level rise is increasing, the trend over recent decades is higher than the trend over the full record.

      What exactly is your point?


    • deconstruct

      EIKE is a well-known climate-denier-group in Germany. They don’t make research, they publish anything climate-relevant in respected peer-reviewed journals, they just make stuff up.

      And BTW: “Again I’ll take his word over yours”: Sure, because it supports what you already believe, not because it has any merit. If it would have, they would publish those things in Nature Climate Change, not on their own blog, where anybody can just write the biggest crap.

  4. According an exposition at a knowledgeable reli site, the planet is shrinking, but the volume of water is not, squeezed out from middle earth, hence the wet feet.

  5. Word for the day.
    Speak or act in an evasive way.
    ‘he seemed to prevaricate when Tamino asked pointed questions’

  6. You can’t depend on Google Translate to do any sort of accurate translation of scientific texts.

    In any case, that EXPERT conclusion is that the best quadratic fit for the data they selected has a negative x² parameter, therefore there is no acceleration. This is stupid because the quadratic term is (a) negligible, (b) not physically plausible and (c) not statistically significant (surprise), which that EXPERT neglected to notice (surprise again).

    I also wonder why you guys harp on the acceleration/deceleration question so much. Apparently that is because the actual fact of rising sea levels are by now so irrefutable that you need to resort to second-order debates in order to keep casting doubt on the whole thing – and detract from the fact that we need to get our collective asses in gear NOW and start plugging CO2 sources instead of continue to build new ones.

  7. ahah

    Denier links to paper written in Klingon to support his claim – shocker

    just when you think you have seen it all!!!

  8. “In the 20th century, while the IPCC claims a sea level rise of 10-20 cm globally, that has not occurred around the Australian coast. According to the National Tidal Facility (NTF) in Adelaide, a survey of 27 long-term tide gauges around the Australian coast (which faces three oceans) found a rate of sea level rise of only +0.3 mm/yr, equivalent to a rise over a century of just 3 cm, not 10-20 cm.
    the 90-year tide gauge record from Fremantle in Western Australia, with a sea level rise rate of +1.38 mm/yr, equivalent to 13.8 cm in a century. Other tide gauges around the Western Australian coast do not support the Fremantle picture at all.
    Here are the NTF figures in mm/yr, sea level rises indicated with +, falls indicated with – for WA.
    Wyndham -0.59, Port Hedland -1.32, Carnarvon +0.24, Geraldton -0.95, Fremantle +1.38, Bunbury +0.04, Albany -0.86, Esperance -0.45.
    The average for all of them, including the errant Fremantle, is a sea level fall of -0.31 mm/yr.”
    The longest, but disputed tidal measure is from Tasmania.

    • Angech, in his usual dishonest style quotes from a post by climate denier John Daly without attribution. You guys really are just sad. Is this really the best you can do, ferchrissake?

      • Tamino is a great mathematician but also a very committed person to the concept that we have to save the world from the problem caused by rising CO2 levels.
        Hence he uses arguments that are persuasive but nuanced.
        While attacking cherry picking deniers he is not ashamed to use the same tactics himself.
        I cannot believe he suffers from cognitive dissonance so he knows what he is doing and believes it is right to do so.
        I think sea level rise and fall is a very touchy subject.
        I have not studied Brest in detail so do not know why Brest was chosen for discussion and demolished.
        Australia is a different kettle of fish and Fremantle is not appropriate to use as a proxy for Australian sea level discussions.
        Is this the best I can do snarkrates?
        I have put up a list of figures, shoot them down if you can. The source of the data is the NTF, National Tide Facility.
        They do not disprove Tamino in any way, just show that Fremantle may not be the right weapon to use.

      • Angech,
        The objection is that you did not cite your source–obviously because you know John Daly has no credibility. How do you think this reflects on your credibility?

      • Mal Adapted

        Tamino is a great mathematician but also a very committed person to the concept that we have to save the world from the problem caused by rising CO2 levels.
        Hence he uses arguments that are persuasive but nuanced.
        While attacking cherry picking deniers he is not ashamed to use the same tactics himself.
        I cannot believe he suffers from cognitive dissonance so he knows what he is doing and believes it is right to do so.

        Gee, Doc, what about you? Why are you here, then? While sea level rise may be a ‘touchy’ subject, for you at least, it is nevertheless occurring, and it’s caused by AGW. Why challenge Tamino or anyone else, great or only quasi-great, on that basic fact?

        I have put up a list of figures…
        They do not disprove Tamino in any way, just show that Fremantle may not be the right weapon to use.

        If I were a betting man, I’d bet that’s not why you put them up.

      • Mal Adapted

        Myself, to angech:

        While sea level rise may be a ‘touchy’ subject, for you at least, it is nevertheless occurring, and it’s caused by AGW. ”

        I had intended to say SLR is not only occurring but accelerating.

      • Sea level rise is accelerating in many parts of the world.
        In many others it is falling.
        It is complex due to glacial rebound, air pressure , sloshing back and forwards in the oceans, rises and falls with ENSO etc.

        One thing to consider is this .
        Nature abhors conformity but man enjoys it.
        When you have disparate areas enjoying the same trends, continuously, for years, beware.
        Tamino may be able to show a global warming trend,
        He can show an Australian warming trend.
        When they both match or rather when people say, look they match exactly, ask y ourself again, how and why?

      • angech shifts topic from questioning the record to attribution. Another time-waster.

    • I think you’ll find that the report that you are referring to is so old that it is pretty much meaningless in this context. Can you provide a reference? Have you read this report, or are you just quoting from somewhere else?

      A much more up-to-date analysis of Australian sea level is here: http://www.sciencedirect.com/science/article/pii/S0012825214000956


    • Neil White, the ‘report’ comes from this web page – an old post by John Daly (dec.) on his website (bibliography is at the bottom of that page).


      The main argument is that Pugh et al (2003) were wrong to conclude that the Port Arthur sea level mark carved into the rock in 1841 was set at high tide, rather than at mean sea level. angech has quoted a portion of the post arguing that Fremantle was a poor choice to benchmark Port Arthur.

      To Daly’s credit, he visited the site and collated a lot of historical information (some gathered from Pugh et al) I found it an interesting post, relatively free of the usual skeptic rhetoric, but ultimately unconvincing*. No doubt you’re well up to date on the matter, but you may find the post of interest if you’re not already familiar with it.


      * If the sea level mark was set at mean sea level, high tide would have flooded the nearby penitentiary: there is no record of that ever happening.

      * Using historical SOI values to infer that sea level was low in 1888, when the mark was re-benchmarked:

      From what I gathered, correlation between ENSO fluctuation and sea level is low that far South. Even if they correlate I’m not sure that sea level effects are pronounced at the onset of el Nino, with weak el Nino values indicated by the SOI for the re-benchmark in 1888, or that sea level effects propagate immediately from the ENSO region to Port Arthur – the two months prior to the setting of the mark had strong Nina values (but only for those two months).


  9. You’re showing great restraint, Tamino. You provided the analysis showing acceleration of tide-gauge data and Wakefield hasn’t shown where you’re wrong. Instead he keeps referring to other stuff. You keep trying to get him back on topic but he refuses. What do we conclude?

    • @Mike Roberts, @Tamino,

      It is difficult to tease out motivations, but I have observed — and participated in — discussions with Science Deniers in many places online. This one fits a pattern I’ve noticed.

      When someone has mentioned something contrary to climate or physics (the trolling phase), like our guest (@J Richard Wakefield), and someone with a bit o’ knowledge comes by to refute it, the original party or another, spouts something quasi-scientific, which the Knowledgeable then goes on to refute again, this time investing some work. The Denier then either moves on to other things, leaving the refutation unchallenged, or says something ridiculous, often based upon a misquote or cherry-pick from some otherwise reputable journal paper. This goes on, consuming ever more time and effort on the part of the Knowledgeable.

      I have a hunch, that in addition to causing grief and making it seem, if this is done in a public forum, that the Knowledgeable cannot refute the reason why climate science is alarmism, strategically, it is intended to tie up more and more resources of people who otherwise could be doing useful work on climate science and public education.

      Where’s the line to draw? To the degree to which it is important to establish to the casual public that the objection of the Denier is groundless, I think it’s worth continuing. To the degree to which the point is simply to show the Denier they are incorrect and convince them, it is a waste of time.

      Anyway, that’s my opinion.

      [Response: I think you hit the nail on the head. In this case, I was able to make blog posts about it which can be informative to general readers.]

  10. Google didn’t translate but I got the gist. The same ‘analysis’ has been posted at familiar English language ‘skeptic’ sites. Apparently it was beyond Wakefield’s ability to discover those. It took me a whole 10 seconds.

    The comparison is between GRACE (gravimetric) and ‘TOPEX/POSEIDON/JASON’ (altimeter) satellite-derived sea level trends.

    Problem is, the time periods are different in the German article.

    GRACE: 2002-2011*
    TPJ: 1993-2014**

    Here is the comparison with equal time period.

    TPJ 2002-2011: 2.3 mm/yr (+/- 0.4)
    GRACE: 2002-2011 1.7 mm/yr (+/- 0.8)

    The German blog-mess cited the rate of 3.2 mm/yr 1993-2014. Mismatching the time periods raised the altimetric trend by 26%.

    This is the quality of ‘analyis’ that excites Mr Wakefiled.

    Over the same time period these figures are not statistically different, but worthy of interest. The satellite uncertainty is probably larger than +/-0.4 mm over that period: I used the long-term uncertainty value.

    The disagreement between the mean trends, according to the authors of the GRACE estimate is almost entirely due the steric component (thermal expansion/salinity) of seas level change, which the authors caution is highly uncertain in their analysis. The changes from mass balance in ice/water are very similar for GRACE-derived and the other satellite estimates. You can read about that at the link below.


    * April 2002 to May 2011, to be exact. That’s the time period I regressed ‘TPJ ‘ data. Source, Uni of Colorado

    ** Mid 2014, presumably – the German blog page is dated 8 July 2014

  11. Lest he object to my using some fancy-schmancy “college boy” mathematical smoothing method, let’s use something as simple as it gets …

    Oh dear, if that’s how smoothing is viewed, I guess I have no hope with my Kalman-inspired filtering and smoothin’ stuff ….

    Until, of course, the next time Mr Wakefield boards an aircraft and puts his own life and those traveling with him in the complete control of such highfalutin darn college boy mathematics ….

  12. Mal Adapted

    When an AGW-denier insists that a ‘Dipl. – Metereologe’ holder has overturned consensus climate science, you have to wonder who told him science isn’t a fundamentally collective enterprise.

    Has Mr. Wakefield ever heard of ‘intersubjective verification’? Is he not familiar with Feynman’s dictum, “The first principle is you must not fool yourself, and you are the easiest person to fool”? Is he unaware that even a senior investigator depends on her peers – specifically, other scientists who are trained in the same scientific sub-culture and have published their own related work – to tell her (and us) when she’s fooling herself?

    And, when an AGW-denier says climate scientists are colluding to bias the published record of their field in favor of AGW, you know the denier has never published a peer-reviewed paper himself 8^D!

  13. Why not to use Fremantle despite it being a very long record.
    “A combination of independent evidence (continuous GPS, repeat geodetic leveling, groundwater abstraction, satellite altimetry, and tide gauge (TG) records) shows that the long-recording Fremantle TG has been subsiding in a nonlinear way since the mid-1970s due to time-variable groundwater abstraction. The vertical land motion (VLM) rates vary from approximately −2 to −4 mm/yr (i.e., subsidence), thus producing a small apparent acceleration in mean sea level computed from the Fremantle TG records.
    Nonlinear subsidence at Fremantle, a long-recording tide gauge in the Southern Hemisphere
    AuthorsW. E. Featherstone,N. T. Penna,M. S. Filmer,S. D. P. Williams
    First published: 27 October 2015Full publication history”

    • @angech, and all,

      I’m certainly supportive of pushing back on Deniers spouting nonsense about SLR, but, on policy, I say let the 15-30 cm-rise-in-a-fortnight happen, real estate prices plummet, and then let the Deniers have a conversation about it.

      • Except that we’d like to limit CO2 so that there won’t *be* that much of a rise. Or plummet. Wishful thinking, given the graphs from Mauna Loa, but still …

      • @smurfix,

        Actually, committed warming and climate hysteresis is such that even if emissions were zeroed tomorrow, oceans will rise a half dozen or so meters. This is all because of our collective emissions. This rise includes thermosteric, and loss of, for instance, the West Antarctic Ice Sheet (WAIS), which is now inevitable. The thing is, is they were zeroed tomorrow, this would play out over the next couple of centuries. However, as we continue to force the climate system with more emissions, we might see catastrophic fractures of ice sheets much sooner.

        There are references for all this in the usual places. I can provide some here, but other than this, which I believe was posted around here recently, I don’t have time to do that right now. See Prof Stefan Rahmstorf’s page, and Science. More.

        This doesn’t count Greenland, which is another sobering story.

      • Mal Adapted


        I say let the 15-30 cm-rise-in-a-fortnight happen, real estate prices plummet,

        You’re talking about my brother’s house, 7 ft above mean high tide in Hampton Roads. It’s long since paid for, but he’s planning to sell when he retires in three years. We’re hoping AGW-denial is still strong in the Tidewater then.

      • @Mal,

        To give you an idea, Woods Hole Oceanographic Institution is working to move their machine shops and labs off Water Street in Woods Hole for these reasons. And that’s expensive!

  14. Satellite record of Australian coast sea level rise matches that of tide gauge estimated.


    Graphical comparisons near the bottom of that document. Page 60.

  15. About ten years ago I happened to attend a lecture by a final year student at Uni of NSW Surveying Dept. The lecture was about the difficulties of connecting the Fort Denison Tide Gauge to a stable onshore benchmark. The distance from the island to the shore is about 500m. This had always been done by trigonometric heighting, a very old and not very accurate technique. He had been experimenting with a new (at that time) Leica instrument which amounted to a more refined version of trigonometric heighting. The conclusion (as far as I remember) was that the requirement to connect the tide gauge sensor accurately to a stable benchmark had never really been possible in the case of Fort Denison, and for the future onshore tide gauges should be preferred.
    Of course recently GNSS has probably solved the problem, but that doesn’t repair the earlier records. The student had looked but was unable to find any good reason why the tide gauge had been placed there.
    I suppose all this is covered in BV Harmon’s article, but that one is not so easy to access.
    I mentioned all this to Phil Watson once, and he acknowledged the problem, but said that as Fort Denison was all there is, it has to be used.