SEA LEVEL: Rise and Fall – Part 5: Bending the Trend

Guest Essay by Kip Hansen — 9 February 2020

featured_imageUSA Today shouts: “Rise in sea levels is accelerating along U.S. coasts, report warns”.   Many other media outlets have repeated the story:  The Guardian, The Hill, and U.S. News and World Report.   All of these make the same claims:

The report’s key message “is a clear trend toward acceleration in rates of sea-level rise at 25 of our 32 tide-gauge stations,” said Virginia Institute of Marine Science emeritus professor John Boon in a statement. “Acceleration can be a game changer in terms of impacts and planning, so we really need to pay heed to these patterns.”

“Although sea level has been rising very slowly along the West Coast, models have been predicting that it will start to rise faster,” the marine science institute’s Molly Mitchell said.”

The National Oceanic and Atmospheric Administration  also has warned about sea level rise acceleration. It has noted that by the end of the century, global sea level is likely to rise at least one foot above 2000 levels, even if greenhouse gas emissions follow a relatively low pathway in coming decades.”…. “On future pathways with the highest greenhouse gas emissions, sea level rise could be as high as 8.2 feet above 2000 levels by 2100,” NOAA warned.” …. “Mitchell said that “seeing acceleration at so many of our stations suggests that – when we look at the multiple sea level scenarios that NOAA puts out based on global models – we may be moving toward the higher projections.”

[ Note:  My West Coast counterpart, Willis Eschenbach, has covered part of this story in an earlier essay today titled: Accelerating The Acceleration, and he does so in his own inimitable mathematical style.  You won’t find much duplication here as I hit it from a different angle. — kh ]

All of the media pieces say “according to a new report.”   There is no new report. The link goes to Virginia Institute of Marine Science (VIMS) website, the page of their U.S. Sea-Level Report Cards.  There was a report last year, which is self-published by VIMS, and is not, as far as I have been able to determine, peer-reviewed.

The news stories all stem from this press release issued by VIMS and written by one of their co-authors, David Malmquist.   And the true source of the data and the “report”?  VIMS emeritus professor John Boon, who retired in 2002 yet still puts out reports claiming Sea Level Rise Acceleration.

How much acceleration?  Let’s look at the data that prompted this news item from KTVU television in San Francisco, California:

ktvu

Here past of what they say:

“Researchers at Virginia Institute of Marine Science (VIMS) issued their annual report card which looked at tide-gauge records for 32 coastal locations, stretching from Maine to Alaska. The analysis included 51 years of water-level observations, from January 1969 through December 2019.

“The key message from the 2019 report cards is a clear trend toward acceleration in rates of sea-level rise at 25 of our 32 tide-gauge stations,” said VIMS emeritus professor John Boon.” 

The KTVU report is one of the few that give numbers to back up these claims (kudos to KTVU):

“San Francisco’s rate of sea-level rise last year was 1.91 millimeter, and Alameda saw a yearly increase of 1.10 millimeter. The sea-level acceleration rate measured at 0.03 mm and 0.05 mm, respectively at those tide-gauge stations. Researchers projected that if this continues, sea level in San Francisco and Alameda will be almost .5 feet higher in 2050 compared to 1992. “  [ emphasis — kh ]

[Technical Note:  All acceleration numbers should be in units of mm/yr/yr or, alternately,  mm/yr2 both in the news pieces and in my essay –kh ]

Let’s look at this in the image provided in VIMS’ report card:

TG_accuracy

Sorry to make that image so BIG, but if I had not, you wouldn’t have been able to see the Sea Level Rise Acceleration at all.  It is those little orange bars right above the zero line.   Note that the official NOAA specification for tide gauges states that the estimated accuracy for tide gauge monthly means is +/- 5 mm.  I have added that range on the chart for your convenience — but I had to stretch the height of the chart to fit it in, because, for the mathematically inclined, the estimated error range for tide gauge monthly means (and thus the above annual trends as well) is 200 times the size of the reported acceleration for the Alameda tide station and more than 300 times of the acceleration for San Francisco.

How does Boon et al. manage to measure these infinitesimal acceleration rates in spite of the oversized known measurement error range?  Like this:

anyport_SLR_Boon_annot

Since at least as early as 2012, Boon and his team at VIMS have been trying to convince the world that “sea level is accelerating!”  They do it by bending the trend line….and then, like all good climate scientists, extending their trend line into the far future.  Of course to do so successfully, they have to have a data set that is not too long — so in this case they start all of their calculations in 1969. The chart above though labeled “Anyport, USA” is in fact the data for Sewells Point (Norfolk), VA.  The real NOAA chart looks like this:

Sewells_Point_NOAA

Boon et al. obscure the data by throwing a “decadal signal” on top of the actual measured data, and then, using their own proprietary formulas, calculate a quadratic trend line for the data segment 1969-2019.  They have been doing this since 2012 — so let’s see how their acceleration predictions have worked out.

Here is the chart from the 2012 report:

Boon_2012_Boston

Boston is shown as having a linear trend of 2.882 mm/yr.  (ignore the ridiculous thousandths of millimeters claim for now).    Here’s NOAA on Boston, showing a rather monotonic steady rise of about 2.8 mm per year since the 1920s.

Boston_Tides_and_Currents_8

But, Boon’s 2.88 isn’t all that different.  At the end of 2011, Boon says that Boston has an acceleration of 0.15 mm/yr.  So by 2015, that rate should be 3.482.  Let’s see….in Boon’s 2015 paper:

Boon_2015_Boston

Ah ha, Boon has shifted to new system of calculation described as “Contoured joint probability density of parameters”, so that instead of simple numerical predictions, we have predictions at “height percentiles”.  But, giving Boon the benefit of the doubt, we’ll look at his mean number (50%) for Boston SLR for 2015, which is now 3.07 mm/yr.   Boon’s 2012 prediction is off by about 15% — relative sea level at Boston, over these four years, only increased by 0.04 mm/yr (if the increase is even in fact real, as it is vanishingly small compared to the know measurement error range).

How about the latest “Report Card” for Boston?  It shows some interesting things.

boston_2019_dual

The chart at the VIMS site is an interactive chart (unlike my modified screen chart above).  Mousing over a data point at the VIMS site gives the numbers I use above and in the following.

There are differences between published Linear Rate data and the chart above, but they are smaller than those for Acceleration data.   The calculated acceleration for Boston does not actually show up in the Linear Rate.  The interactive chart just posted this month shows that Boon found acceleration in 2011 of 0.305 mm/yr at Boston.  Thus, by 2015, four years later, there should have been an increase in the linear rate for the annual single year, 2014, of an additional 1.2 mm — that obviously did not happen.  If we apply the Boon (2012) published acceleration rate of the much lower 0.15 mm/yr for eight years to 2019, it should add 1.2 mm/yr to the linear rate through 2019.   Using Boon’s 2019 Report Card interactive chart, 2011 is shown as 2.93 mm/yr and 2019 is shown as 3.22 mm/yr.  Simple math gives us a difference in linear rates of only 0.29 mm/yr, which, divided by the eight years, reduces to 0.03625 mm/yr — only about one tenth of the 0.305 mm/yr  predicted for 2011 on Boon’s online interactive chart.

Let’s try the 2009 Annual Acceleration Rate of 0.251 mm/yr.  If we hold that constant over ten years, to 2019, it would have meant an Annual Linear Rate for 2019 of  2.411 (in 2009)  plus 2.51 of ten years of Annual Acceleration for an predicted annual Linear Rate in 2019 of 4.921 mm/yr.  The actual calculated annual Linear Rate for 2019 is 3.22.

The point is that the calculated Annual Accelerations are not adding up or showing up over the following years as Annual Linear Rates as predicted by charts such as this:

Boston_2019_Report

Let’s take a closer at just the last decade, covered by the Boon et al. reports discussed above:

Boston_decade_compare

On the left is the NOAA  Tide Gauge at Boston, the same monthly mean sea level data used by Boon, in the segment on the right.    The past decade shows that mean sea level dropped at Boston  starting at 2010 for five years and then rose again to back up to the same level by the end of 2019.  (There may be some data break at 2009, where there is a sudden shift upwards of almost 10 mm in a single month — don’t know if there was any equipment or location change then.)  While there is no doubt that Mean Sea Level at Boston is rising, there is no change that seems any different than the simple assumption of a continued, monotonic steady rise.  Boon’s use of the solid blue line (decadal signal) and the orange “quadratic trend” obscure and confuse the long-term view, as shown in the NOAA Tide Station chart far above.

Interested readers can download the VIMS 2018 report here and refer to their updates for 2019 here.

Bottom Line:

Boon, although long retired,  and his group at VIMS have been touting sea level rise acceleration for almost a decade now.  It is their thing and apparently they are convinced of its truth.

The past published acceleration rates do not actually appear in their own futures — the rates published in 2012 do not appear in the mean sea level increases in 2019.

Any times series, and any segment of a times series, should show an acceleration (change in rate-of-change — faster or slower) over time, as it is unlikely that any real series of measurements of a natural phenomenon remain exactly constant.  However,  Boon’s Acceleration Rates found for the West Coast in the 2019 reports cards are implausibly small given the known Error Range for Monthly Means for NOAA Tide Gauges and I would not consider them statistically significant and certainly not climatically significant.

Developed areas, anywhere in the world, that have been built within a few feet of today’s Relative Mean Sea Level  and local Mean Higher High Water for their locality are already in imminent danger of being damaged by extreme tides, surges from today’s storms and from tsunamis if in areas prone to such.  These localities need to urgently begin mitigation efforts.

For now, most coastal areas should plan on Relative Sea Level continuing to rise at its long-term rate for their locality and in planning, add on extra leeway in case warming waters begin to rise a bit faster.  No one needs to panic or plan for the near-impossibility of multi-meter sea level rises over the next century.

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Author’s Comment:

VIMS and Boon are not the only groups pushing the idea that sea levels are not only rising but that that rise is accelerating.  Nerem and his team at Colorado are pushing — and pushing again —  the same.

Global Mean Sea Level is changing and is generally accepted as rising, as it has done for several hundred years. There is no reason to think that this long-term trend will change on a global basis unless and until the Global Climate either shifts to Radically Warming or Radically Cooling.

Boon at al. demonstrate clearly the dangers of the Over-Mathemati-cation (made up word there) of Science — a Reification of Very Tiny mathematical and statistical results into real world threats.

Note that the featured image is a good example of a not-yet-bent official SLR graphic from  Climate.gov  — the Federal government’s official climate propaganda site.  Click for a full-sized image.

I have written here more than a dozen times about Sea Level.   The series “Sea Level: Rise and Fall” (Parts 1 and 2) starts with some basic principles.

I am interested in what your hometowns are doing in regards to sea level rise.  Let me know.

Start your comment with “Kip…” if speaking to me.

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123 thoughts on “SEA LEVEL: Rise and Fall – Part 5: Bending the Trend

  1. Pretty soon we’ll also be able to identify that “sea level everywhere is rising twice as fast as everywhere” as with warming.

  2. There must be a strange tilt of the water in the Pacific Ocean building up as the water in Sydney Harbour at Fort Denison has risen only 50-mm. in the years from 1886. That’s about 0,36-mm. per annum.

    • nicholas tesdorf ==> One thing we have learned from the Jason series of satellite measurements of sea surface height is what I call “The oceans are not a bathtub”. Putting in water in one place does NOT evenly raise the sea surface height evenly everywhere. There are lots of reasons for this. For an explanation, see here or, if you prefer NOAA, here.

      • But Kip… the different areas of the oceans have long ago equilibrated with the local gravity differences… so why adding water now and any one place raise water levels everywhere? The only difference should be that in some areas land is sinking and in some areas land is rising.

        • At some point in the future….there will be 200ft high mountains of water in the ocean
          …and 200ft deep holes
          It’s not possible for sea level to be ‘trending’ higher in places…and ‘trending’ lower in places
          …those trends could not be sustained

          I don’t think so………….

        • hoppe ==> Did you go to the links I provided? The provide a pretty good idea of why this is so.

          The oceans are not a bathtub — way more complicated.

        • At Panama, the Pacific Ocean averages about 9″ higher than the Atlantic Ocean and at time is several feet higher.
          There are many reasons why sea level measured at seashores can vary around the world. Some are common like temperature, salinity, prevailing winds, local gravity, tides. shape of nearby ocean floor, etc.
          Seashore tidal data measure sea level relative to the local land (which may be rising or falling), whereas satellite data measure the changing volume in the open ocean, which on average is independent from seashore effects, but requires significant corrections for Earth’s shape (geoid).
          Satellite sea rise rates are sometimes increased by 0.3 mm/yr for post-glaciation sinking of ocean basin bottoms (irrelevant to tidal data), but not always

      • observa,
        Good point with this paper and other similar papers.
        See sealevel.info for many papers debunking accelerating sea level rise.

  3. Thank you for the data and analysis- I will pass this on to all my friends who blindly believe the false narrative on Sea level rise. Much appreciated!

    • Louise ==> You’re welcome. Reading the other essays in this series will give you a good introduction into the issue.

      Search this web site for “SEA LEVEL: Rise and Fall”

  4. Kip,
    Have you received any response from Boon?
    It would be great if at least one of his cohorts would admit their analyses were bogus.

    • Willem ==> I haven’t written to Boon or his group about it. I doubt they read this website, either.

      • Kip, I think you’d be surprised by who visits WUWT and other blogs hosted by people skeptical of human-induced global warming and climate change.

        Also, thanks for the post, well done.

        Regards,
        Bob

        • Bob ==> Thanks…and I actually have been surprised in the past by who reads here — I often get emails from people I never would have thought even consider reading WUWT,

      • I am sure someone will make him aware of it. They’ll just bury their heads in the sand. Some blogging buffoon will find a typo or reference a mistake made in a posting on this website in 2014 and then act like it makes the entire commentary bogus.

      • Kip,
        The Dutch have had an interest in the sea level. for centuries.
        About 40% of the country us up to 6 METERS below sea level.

        Sea level rise in the Netherlands
        https://www.climatechangepost.com/netherlands/coastal-floods/

        Past

        Since 1900 sea level rise of the North Sea near the Dutch coast has been 19 cm, which is comparable with the global average (4). In addition, there is subsidence of the Dutch soil up to 8 mm/year, depending on the location in The Netherlands (52).

        Future

        According to the most recent scenarios of the Royal Netherlands Meteorological Institute, sea level on the Southern North Sea will be 25 to 80 cm higher in 2071-2100 (averaged year 2085) than in 1981-2010. For 2100 an upper level of sea level rise is projected of 100 cm (46). In addition, the subsidence of the Dutch soil will continue up to 4 mm/year, depending on the location in The Netherlands (4).

        Greenland and Antarctica tend to lose more ice than was presented in the last report of the IPCC (AR4). Observations in the period from 2002 to 2009 show that the mass loss of both ice sheets has accelerated over time, implying that the ice sheets contributions to sea level rise also becomes larger over time.

        For 2100, the high-end projection for global mean sea level rise is higher (0.55 -1.15 metres) than global estimates, as reported by the IPCC AR4 (0.25-0.76 metres), compared to 1990 levels.

        This implies a rise along the Dutch coast of 0.40 to 1.05 metres, by 2100 (excluding land subsidence) (23).

        • willem==> The ONLY thing that matters for SLR is the Relative SLR at any particular locality.

          At Hook Van Holland, according to PSMSL, there has been about 400 mm of SLR since 1864 — a long-term rate of 2.56 mm/yr, with no acceleration shown in the data.

          See the data at https://www.psmsl.org/data/obtaining/map.html#plotTab

          Blow up the map and select Hook Van Holland (it is on top of The Hague). Select “Plots” in the pop-up window.

          Try some of the other stations in the Netherlands — select WHITE ones, as they have the longest/latest data.

          NONE show any appreciable acceleration — all monotonic steady rises.

          • Kip: I agree FWIW. 2.56 mm is essentially 1 inch every 10 years. It is hard for me to see how Willem’s sources get to the numbers he reports. The low end estimate is pretty reasonable, i.e. 10 inches. The upper end – 30 inches assumes a significant acceleration starting very soon.

          • Kip,
            Their report states they foresee acceleration for various reasons.
            Till now no acceleration.
            We will just have to wait and see if it will happen.

            I was born in Rotterdam, 6 meter below sea level, left before the Delta Plan was started.

          • Willem ==> I sympathize with you — there are a lot of people “foreseeing” bad things in the future for the rest of us. They have been doing it since 1988 — and before that, predicting Global Cooling.

            And, you are right on target — “till now, no acceleration”.

            The rate of Sea Level change may change in the future, faster or slower — we just can’t tell.

          • Willem ==> I sympathize with you — there are a lot of people “foreseeing” bad things in the future for the rest of us. They have been doing it since 1988 — and before that, predicting Global Cooling.

            And, you are right on target — “till now, no acceleration”.

            The rate of Sea Level change may change in the future, faster or slower — we just can’t tell.

  5. Most published research findings are false. link

    … a research finding is less likely to be true
    when the studies conducted in a field are smaller;
    when effect sizes are smaller;
    when there is a greater number and lesser preselection of tested relationships;
    where there is greater flexibility in designs, definitions, outcomes, and analytical modes;
    when there is greater financial and other interest and prejudice;
    and when more teams are involved in a scientific field in chase of statistical significance.

    Boon et al’s work trips most of the alarm bells for bad science.

    The small effect size is well within the error bars of the data.

    Analytical modes = funny math

    Prejudice – hey, it’s climate science. Guilty until proved innocent.

    More teams – folks trying to find something grant worthy that corresponds with ‘the narrative’. Getting published is very competitive and it’s akin to a blood sport.

  6. When you dig arounds VIMS online stuff you find funding things like this:

    “The Virginia Institute of Marine Science and William & Mary’s Law School are collaborating on a new website that will provide key information to support local, regional, and state efforts to adapt to climate change, thanks to state funding and a $1.2 million grant from blue moon fund.

    The grant will provide funding for the Virginia Coastal Adaptation Data Portal, a website that will give a wide variety of information, data, analyses, and tools useful for risk assessment and adaptation planning. Hampton Roads has the highest rate of sea-level rise on the East Coast, putting the region at a heightened risk of recurrent flooding and stormwater damage.”

    “The blue moon fund
    This is the third grant blue moon fund has awarded the university. The Virginia Coastal Policy Center received $178,500 from blue moon fund last year; and in 2014, VIMS received a $150,000 grant from blue moon fund for related work.”

    source: https://www.vims.edu/giving/impacts/data_portal.php

    So VIMS got more than $1.5 million from the VBlue Moon Fund to advocate. Ya’ gotta wonder who else is giving VIMS money.

    Like all things “Green,” follow the money….
    According to InfluenceWatch.org, the Blue Moon Fund went defunct not long after that last grant to VIMS in 2016.

    Just who is the Blue Moon Fund?

    “The Blue Moon Fund was born out of a breakup of the W. Alton Jones Foundation. The W. Alton Jones Foundation was created by former oil executive Alton Jones in 1944 from oil revenues of the Cities Service Company. ”

    “Organizations Blue Moon funded included the World Wide Fund for Nature (formerly World Wildlife Fund),[10] Sierra Club, Natural Resources Defense Council, Environmental Working Group, Greenpeace, the Nature Conservancy, Friends of the Earth, Worldwatch Institute, Environmental Defense Fund, and affiliates of the League of Conservation Voters. ”

    Other recipients of money from the Blue Moon Fund are:
    Appalachian Voices (Non-profit)
    Center for American Progress (CAP) (Non-profit)
    Ceres (Non-profit)
    Environmental Defense Fund (EDF) (Non-profit)
    Environmental Grantmakers Association (Non-profit)
    International Labor Rights Forum (Non-profit)
    Mountain Association for Community Economic Development (Non-profit)
    The Nature Conservancy (TNC) (Non-profit)
    New Venture Fund (NVF) (Non-profit)
    Rockefeller Family Fund (Non-profit)
    Trust for Conservation Innovation (For-profit)
    West Virginia Center on Budget and Policy (Non-profit)

    In 2005, Diane Edgerton Miller, the then CEO and President of the Blue Moon Fund, was on the International Board of Directors for the Global Environmental Institute based out Beijing, China. Partners of GEI included the People’s Republic of China National People’s Congress Environment and Resources Committee and the Central School of Communist Party, among other Chinese government entities.
    https://www.influencewatch.org/non-profit/blue-moon-fund-cassiopeia-foundation/

    You gotta wonder why Blue Moon Fund would be giving money to CERES.org, or the Rockefeller Funds?

    The GreenSlime has been hard at work for several decades now pushing the climate scam and deeply funding “academics” who push the proper narratives.
    Oh, and maybe Trump WAS right about the Chinese.

  7. Kip , here’s the comment I sent to Willis a couple of hours ago. I’ll include the Bolt interview plus the data from the BOM since 1914. Here’s the BOM MSL data since 1914 + You tube interview below.

    Thanks for this post Willis and even I can follow most of it.
    Can you have a look at Andrew Bolt’s interview with Daniel Fitzhenry + data for Fort Denison Sydney a few months ago and tell us what you think about the claims?
    A lot of people seem to dispute the claims made, thanks again for your interesting posts to WUWT over the years. Here’s the link.

    http://www.bom.gov.au/ntc/IDO70000/IDO70000_60370_SLD.shtml

    Here’s the Daniel Fitzhenry interview by Andrew Bolt.

  8. Near me in Rochester Michigan is Lake Huron and lake level is record high with corresponding erosion of shore, some roads in danger of washing out. The climate models said the Great Lakes would dry up? This would be a good topic for a story here, or anywhere.

    • John Bell ==> The Great Lakes are a fascinating story — I may look into it but I’d have a real steep learning curve.

      My first brush opinion is that Great Lake water levels are chaotic.

  9. According to FitzHenry, in addition to the gravitational effect of the moon, planetary alignments contribute to tide levels. Has that really been shown to be the case? Anyone? Thanks.

  10. Work done by Phil Watson does not support accelerated sea level rise. He only found one tidal gauge in Europe with accelerating tidal rise. The rest were constant or had minor de-acceleration.
    A paper he wrote in conjunction with Doug Lord in 2009 was actively suppressed by the NSW Government. Eventually a new paper was published in 2011.
    Watson P.J and D.B Lord (2008). “Fort Denison Sea Level Rise Vulnerability Study”, a report prepared by the Coastal Unit, NSW Department of Environment and Climate Change, October.
    Watson, P.J., (2011): Is There Evidence Yet of Acceleration in Mean Sea Level Rise around Mainland Australia? Journal of Coastal Research: Volume 27, Issue 2: pp. 368 –377
    Watson, P.J., 2016a. Identifying the best performing time series analytics for sea-level research. In: Rojas, I. and Pomares, H. (eds.), Time Series Analysis and Forecasting: Contributions to Statistics. Cham, Switzerland: Springer International, pp. 261–278.
    Watson, P.J., 2016b. How to improve estimates of real-time acceleration in the mean sea-level signal. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium. Journal of Coastal Research, Special Issue, No. 75, pp. 780–784.
    Watson, P.J., 2016c. Acceleration in USA mean sea-level? A new insight using improved tools. Journal of Coastal Research. In press. doi:10.2112/JCOASTRES-D-16-00086.1
    Watson, P.J., 2017. Acceleration in European mean sea-level? A new insight using improved tools. Journal of Coastal Research, 33(1), 23–38. Coconut Creek (Florida), ISSN 0749-0208.

  11. Why is acceleration being stated in mm/yr? Shouldn’t that be mm/yr/yr, or some other length/time/time units?

    • Scarlet ==> ABSOLUTELY! They are actually in mm/y2. I have been lazy in the notation used in the essay — but have included the charts from Boon et al. which shows the correct notation.

      I’ll add a note at the beginning to clarify.

  12. “…using their own proprietary formulas, calculate a quadratic trend line for the data segment 1969-2019…”

    I am sure the quadratic trend line comes from first principles and is supported by historical data, just like every other prediction/projection in climate science, lol.

  13. Kip,
    the claim that the mean error for monthly tide data is “is 200 times the size of the reported acceleration”
    is nonsense. There is no meaningful way to compare data with different units. High tides are reported in
    metres above some reference level while acceleration has units of m/year^2. Similarly in your second figure
    you have deliberately added a blue line with an arbitrary scale to distort the meaning of the graph. The
    VIM interactive chart is very careful to use the correct units for all measurements and also to use two seperate scales when necessary. It would be good if you did the same.

    • Izaak ==> It is Boon’s graphic, with my annotations. Boon et al. include both the Rise/Fall rate in mm/yr and the Acceleration in mm/y2 on the same chart, with the scales in the key at the bottom. I add the acknowledged Accuracy Range for Tide Gauge Monthly Means.

      Boon, like many other Sea Level sites, including NOAA, use graphics that contain no error bars, creating misleading information.

      The tide gauge monthly mean error estimate, from NOAA, is in fact 200 and 300 times the annual acceleration claimed by Boon.

      • Kip,
        Again the statement that “The tide gauge monthly mean error estimate, from NOAA, is in fact 200 and 300 times the annual acceleration claimed by Boon” does not make any sense since the mean error and the acceleration have different units. 5 mm divided by 200 is still a length and no numerical factor can change that to a measurement of mm/yr^2. Graphing things with different units on the same graph is an excellent way to trick people as I am sure you know.

        • Regardless of your nit. Due to the very large error bars, we don’t even really know if sea levels are rising or falling.

          • Hi Jeff,
            If we wait long enough we can say whether or not the sea level is rising. Tide gauge data goes back over a century in many places and a sea level rise of 1mm/yr over the course of several decades becomes larger than the mean month error.

          • Izaak ==> Yes, and after 100 years, we have not seen that rise in absolute sea level at tide gauges. See the NOAA Tide Gauge Record for Boston included in the essay.

          • Jeff ==> With the magnitude of the difference between error bars on monthly means and the posited “acceleration per year” for those two west coast stations — it isa implausible that any kind of analysis could come up with a valid number that very small.

          • Kip,
            I am not sure what you mean regards Boston. In the essay you state “Here’s NOAA on Boston, showing a rather monotonic steady rise of about 2.8 mm per year since the 1920s.” Now 2.8 mm/yr*100 yr = 280mm which is significantly larger than the NOAA error bars of 5mm. And indeed sea level rise looks obvious in the graph you gave showing the sea level from 1920 till today.

          • “Izaak Walton February 9, 2020 at 6:43 pm

            Hi Jeff,
            If we wait long enough we can say whether or not the sea level is rising.”

            Sea level gauges have been in use around the old naval ports of the British navy for HUNDREDS of years! Show nothing to worry about.

          • “Izaak Walton February 9, 2020 at 6:43 pm

            Hi Jeff,
            If we wait long enough we can say whether or not the sea level is rising.”

            If we wait long enough, all the inner planets will be consumed by a dying star!

          • Izaak ==> This essay is about Boon’s claim of acceleration of sea level rise. A change in relative sea level that is accelerating at 1 mm/yr/yr would show something like 2 mm rise this year, 2.1 mm next year, then 2.2 mm, then 2.3, then 2.4 — the annual rate would keep increasing by the amount of the acceleration. Imagine a ball rolling down an incline — it accelerates as it goes, moving faster each second,

            Boon claims that sea level rise, the annual change at Boston, is accelerating. In 2012 , the claimed at the end of the year 2011, Boston’s sea level was rising at an accelerating rate of 0.305 mm/yr/yr. So in 5 years, the annual rate in 2016 should be, if he is right, the rate of 2011 — 2.93 mm/yr, PLUS an additional 1.525 mm/yr (5 times 0.305) , which should result in an annual rate in 2016 of 4.455 mm/yr. Yet in 2016, the rate was only 3.065 mm/yr. The claimed acceleration did not actually take place.

            Relative Sea Level at Boston has risen aby about 280 mm over trhe last 100 years — about 11 inches, which is well in line with generally accepted Global Sea Level rise over the same period — I gave the NOAA Tides and Currents chart for Boston in the essay. This graph shows a long steady, monotonic rise over 100 years, with no acceleration.

          • Patrick MJD February 9, 2020 at 10:00 pm
            “Izaak Walton February 9, 2020 at 6:43 pm

            Hi Jeff,
            If we wait long enough we can say whether or not the sea level is rising.”

            Sea level gauges have been in use around the old naval ports of the British navy for HUNDREDS of years! Show nothing to worry about.

            Tell that to the residents of Key Largo who by November 28th last year had been flooded for 82 days.
            https://media.npr.org/assets/img/2019/11/27/gettyimages-1182769212_custom-91ac7bb3077bec98ff93b5c5429eec92d5814744-s1600-c85.jpg

          • Phil ==> Key Largo is flooding because it is built INCHES above Mean High Water, and when it gets exceptional tides (all perfectly normal without any SLR involved) they flood.

            There is actually data about why Key Largo is flooding and why their highest tides are higher than usual. But absolute sea level rise has very little to do with their problems.

          • “Kip Hansen February 10, 2020 at 9:24 am”

            Correct. The town of Emsworth in Hampshire is very low lying and floods at high tides. Nothing unusual about that, nothing to do with SLR either.

          • Kip Hansen February 10, 2020 at 9:24 am
            Phil ==> Key Largo is flooding because it is built INCHES above Mean High Water, and when it gets exceptional tides (all perfectly normal without any SLR involved) they flood.

            Yes that’s the way it used to be but last fall it stayed flooded for over 82 days, now that’s an exceptional tide!

          • Phil ==> Sue it did, and the main cause has been found to be increased prevailing winds pushing the water of the Atlantic west, increasing tides there.

          • “If we wait long enough we can say whether or not the sea level is rising.”

            Like “global temperature”, there is no “global sea level”. It’s another fantasy concept that isn’t helpful to anyone but those with an agenda.

        • Yes after commenting in the update that the units are not consistent you continue to show a bogus graph comparing monthly mean accuracy with annual trend rates and annual acceleration rates.
          You don’t even use the same time unit, why not use the annual uncertainty not the monthly, not scary enough for you?

          • Phil ==> Not my graph — just my annotation.

            I use the Monthly Mean uncertainty because NOAA gives that expressly — NOAA doesn’t give an expressed value for the uncertainty of its annual means — annual means are made from 12 monthly means — and can’t be reliably physically more accurate than that.

            You seem to involve yourself in the minutia of the images (created and supplied by Boon) and thus missing the point of the graphic itself and the essay overall.

          • Kip Hansen February 10, 2020 at 9:21 am
            Phil ==> Not my graph — just my annotation.

            I use the Monthly Mean uncertainty because NOAA gives that expressly — NOAA doesn’t give an expressed value for the uncertainty of its annual means — annual means are made from 12 monthly means — and can’t be reliably physically more accurate than that.

            Your post, you’re responsible for it.
            You should learn some stats.

          • Phil ==> The mis-use of Stats is the problem, not the solution.

            The use of stats to obscure and hide uncertainty is one of the major problems of all scientific research today — in all fields.

          • Kip Hansen February 11, 2020 at 7:07 am
            Phil ==> The mis-use of Stats is the problem, not the solution.

            Indeed that’s exactly what you are doing!
            The uncertainty in the acceleration is not the same as the uncertainty in the rate of change and not the same as the uncertainty in the monthly mean sea level.
            Also the uncertainty in the annual mean is not the same as the uncertainty in the monthly mean.
            Regarding the VIMS data you showed you claimed:
            ” The calculated acceleration for Boston does not actually show up in the Linear Rate.”
            Actually it does, the linear rate shown increases from year to year, that is acceleration!
            Your calculation appears to think that the acceleration should be constant, there’s no reason to expect that.

          • Phil ==> There will be another post on this topic soon, from another author, with more data on this.

            It is a simple fact that Boon’s figures are 1) Fabricated by the use of a short segment of the data available and 2) His Calculated acceleration does not show up in the actual Relative Sea Level at the tide gauge in Boston.

  14. One of the challenges to figuring out if sea level is rising or falling or not is that of measurement. All measurements of height require reference to a fixed point. For short term measurements this is not a problem. For example setting out a road development or levelling a piece of ground. With long term measurements there is a problem of what to use as a datum. Terrestrial datums are fine as long as they stay put. That is a problem because continents drift over time, some rise up, some fall. This usually doesn’t happen quickly but it does have an effect on measurements. So to avoid this, we turn to satellite data. All well and good if the satellite stays put or flies a perfect orbit. Satellites do not. Their orbits require frequent adjustment to keep them in their target altitude range. Even geostationary satellites need frequent adjustment. It seems there is some attempt made to correct for this altitude fluctuation in the data but it is not possible to eliminate the effect and thus there is an error factor. So neither terrestrial nor satellite data can ever be truly objective.

    • Pete — You’re not wrong. However, “they” do attempt to address the multitude of problems. For example, they have not one, but three, position measurement technologies over and above ground tracking — GPS, laser reflection mirrors, and DORIS which is sort of a backwards GPS with ground stations providing reference signals to a tracking system on the satellite. If you are curious, download the Jason3 product handbook from https://www.ospo.noaa.gov/Products/documents/hdbk_j3.pdf

      Section 5 addresses many of the measurement problems and how they are handled.

      There are similar handbooks for earlier satellites in the series.

    • Pete ==> NOAA has the Continuously Operating Reference Station (CORS) which is intended to measure land movement — north, south and vertical (up and down). They have a map that you can check to see if any particular area is rising or falling.

      It takes years of data from an individual station to get a decent idea of long-term Vertical Land Motion. But CORS occassionally publishes papers giving the results of calculations for various locations.

      For sea level calculations, tide gauge data must be accompanied by a continuous GPS station mounted on the same structure as the tide gauge — there is an international effort called CGPS@TG(SS) which allows us to know the vertical movement of the pier or dock or whatever so we can calculate how much the sea surface itself is rising or falling by removing the vertical land motion from the tide gauge data.

      • Thanks Kip and also Don K. I have read the JASON handbook and am familiar with CORS. The measures that both CORS and JASON employ are very effective but only in the short term. They are not perfect as we know, hence the published error factors. It will be interesting to see how it plays out over the long term

        • Pete ==> The most interesting thing to me, inthe whole Sea Level saga, is that CORS corrected tide gauge global SLR calculations do not show the same magnitude of SLR as the satellite data — still that glaring difference

    • ”So neither terrestrial nor satellite data can ever be truly objective.

      Well Pete all I can say is pop on down to Gondwanaland and go and visit the Olgas near Ayers Rock or the Bungle Bungles in the north of Western Australia and stand and look at those great walls or beehive formations and what will you see? Layers upon layers of embedded round rocks worn that way by water like stones on a beach or a river bed and they’ve been subsequently overlain by silt and sand and compressed into solid rock and then worn away for all to gaze upon and gasp at their own immaterial insignificance in the great cosmos and sweep of time immemorial.

      In this ancient land and it’s tide gauges founded on that rock anywhere for the last millenia is the true earth datum point to rule the world and what they show is the doomsters are deluded and full of hubris. Anyone who can stand before those walls and then deny tide gauge readings rooted in Gondwanaland is a block a stone a worse than senseless thing and deserves to be embedded in them. Our satellites merely orbit and pay homage to the unfathomable creation of those walls and the continent they stand upon now.

      • When you’re looking at those walls and then way off to the west you can’t help wondering how tall those Peterman Ranges were before they supplied those round stones in those walls-
        https://www.ayersrockresort.com.au/uluru-and-kata-tjuta/natural-environment/geology
        You’ll get the picture that mountain ranges like the Alps Himalayas and Rockies are juvenile ranges by comparison and why at some stage you have to accept a stable land platform and datum on the earth’s surface and you’re standing on it dummy. No not New Zealand as that’s still bubbling up out of the mantle and not puny man made machines whizzing overhead. Duh!

        • Thanks for the replies Observa. I live in Gondwanaland. In Queensland, actually. I know our great continent is considered one of the most geologically stable on the earth, but how do we objectively know it isn’t slowly rising or sinking or tipping or rotating? Against what can we measure it? Another land mass which we also can’t be sure isn’t doing the same things? If two continents are drifting north at the same rate and remain the same distance apart, they appear to each other to be not moving but they are, relative to what, exactly? A third continent which could be doing the same things? And satellites which triangulate their position relative to other satellites and ground stations. If the ground station rises up, the satellites maintain their altitude relative to the ground because there is no other fixed datum to reference. Do you see where error can creep in over time?

  15. Kip
    Thanks for the article.
    Question- why did sea level rise from the 1930s to 1970s when the temperature did not?
    It is my understanding that we don’t know.

    • Waza ==> The short answer is that Global Sea Surface Height (almost the same as GMSL) is not that simply tied to atmospheric temperature.

    • Waza — as Kip says, sea level isn’t that closely tied to temperature. When last I looked, the IPCC sea level rise budget attributed about half of sea level rise to expansion of the oceans due to long term warming of the water after the Little Ice Age. What’s presumably going on is that it takes of LONG time — perhaps many centuries — for surface warming or cooling to slowly work it’s way toward the depths. So expansion or contraction of the oceans tends to be slow and steady rather than closely tracking air/water surface temperature trends. So far as I know, that view isn’t terribly controversial.

      It does suggest that the current modest sea level rise is likely to continue for a long time no matter what happens with air temperatures.

      • “So far as I know, that view isn’t terribly controversial.”

        Perhaps not, but based on what we know, I’d say it’s a SWAG.

  16. Kip: Thank you sir. The claim of accelerating sea-level rise is one of the most egregious and blatant lies coming out of the warmist camp.

    Thank you for your objective rebuttal. I just wish it received wider publication.

    • Mike Smith ==> There is a rather desperate attempt to “make it true” through repeated assertion.

      Their first and most egregious is what is still posted on the NOAA site: “The Jason global mean record shows sea level rising at about 3 mm/year, nearly twice as fast as during the last century.” They know that this is not a REAl change in the world’s sea surface height — only a change from one measurement system to another.

    • Mike,
      Firstly there are a lot of very good reason to believe that sea level rise is accelerating. Firstly
      the thermal expansion coefficient of water increases with temperature and we know that the
      temperature is rising steadily. Secondly we also know that ice loss from glaciers is also increasing
      (as a result of satellite based mass balances). Kip has not refuted this. What he has done and has
      done so fairly well is show that at the present time an acceleration is tiny and within the noise of
      standard measurement and analysis techniques.

      • Acceleration means a change in rate of change. “Rising steadily” literally means, therefore, not accelerating. And the actual degree of correlation of surface temperature and total sea-water volume, given the variability of water temperature throughout the breadth and depth of the world’s oceans must be variable.

      • “we know that the
        temperature is rising steadily.”

        No, it rises and falls in steps, plateaus, ups and downs. Unless you smooth the data so much that you only see it go in one direction.

    • Well the climate changers get total amnesia if you put too long a historical period in their heads so naturally Kip is trying to keep it simple for them by sticking to their hysterical period. Stick with that shorter subset or you’ll bamboozle them completely.

    • Clyde ==> The very long term changes are not that pertinent for planning purposes for places like Huntington Beach, California.

      RSLR is an important and ongoing issue for low-lying coastal cities — and they’d better get themselves in gear to deal with 1) The present day dangers and 2) the fifty to 100 year dangers.

      What they don;t need to do is panic about infinitesimal (possibly imaginary) slr acceleration.

  17. Change in change is the definition of acceleration.
    If you use the tidal gauge figures and look for the trend You will find it.
    50 years average centred around each five years during the long period of yearly averages shows a remarkable periodic acceleration and retardation of the trend.
    https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?plot=50yr&id=9414290

    In Sweden a professor, now responsible for IPCC reporting, showed an acceleration of the rise but the paper did not pass the quality check. But his BIAS made him find something that was not there, or at least only was there for a short period of time. Periodic is the short answer to acceleration!

    • Lasse ==> Thanks for the link — neat graph.

      I tried to make this point when I said “Any times series, and any segment of a times series, should show an acceleration (change in rate-of-change — faster or slower) over time, as it is unlikely that any real series of measurements of a natural phenomenon remain exactly constant. ”

      I’m not sure of the scientific value of “Variation of 50-Year Relative Sea Level Trends” — every 50 year period of any natural world time series will show varying trends. I’m not sure that they tell us anything interesting or important. Maybe if these variations were compared across a hundred stations, they might show oscillations in global values?

      • There are many like this.
        If you find one you find more
        At least they show the variation and the lack of acceleration.
        If there are acceleration each value should be bigger the the one before.
        Remember a value for each Year consists of at least 365 days and many readings a day.
        A 50 year mean of 18 250 days and all comes into these nice curves.

  18. The following quote tells you all you need to know about the scientific objectivity of VIMS:
    https://tidesandcurrents.noaa.gov/sltrends/sltrends.html

    Most of the tide-gauge stations that provide the data used in our sea-level report cards began operation in the first few decades of the 1900s or even earlier. However, many stations—particularly along the U.S. East Coast—show evidence of a non-linear change or acceleration beginning in 1987, at the center of a 36-year sliding window beginning in 1969—thus setting the start date for our sea-level report cards. In short, we use post-1969 data because the linear sea-level trends of earlier decades do not accurately predict the sea-level changes that are most likely to occur given more recently observed acceleration in the rate of sea-level rise.

    Amazing. So they openly admit they crop the data to get more “acceleration” . The more linear part of the data don’t count because they would give less acceleration… which they know is there “given” the fact they cropped the data to create it.

    Seems like Occam must be using those new politically correct Gillette safety razors nowadays. You know, the ones free of “toxic masculinity”.

  19. Kip:

    At the end of 2011, Boon says that Boston has an acceleration of 0.15 mm/yr. So by 2015, that rate should be 3.482.

    That “rate” without units is not a rate it is a sea level rise. Despite the corrective note you put in, you have totally confused mm/yr and acceleration throughout and plotted accel in “mm/yr” on top of a graph sea level “rate” and made a big thing about how you had to make it bigger since the accel was so small and compared the accel figure to the uncertainty in individual tide gauge readings ( ie neither rate nor accel but sea level ).

    Not only is that apples and oranges but shows a woeful lack of understanding of the whole process of data analysis and fitting and relevant uncertainty.

    Please learn the basics or get your worked checked over by someone who does before going public. This kind of thing just makes skeptics ( and WUWT in particular ) look stupid and ill-informed.

    I appreciate your wish to push back on this alarmist crap but that does not get you a free pass. This is not helpful. If Mann did this sort of thing I would rip into. Honesty and objectivity is essential in science and I can’t criticise others yet not criticise you because your heart is in the right place.

    If you step outside what you are experienced in, please get it checked first.

    • Greg ==> NONE of the graphs in this essay are mine — they are all from Boon or NOAA. If they have faults they are theirs and not mine.

      I will repeat what I have said above to IZAAK:

      “This essay is about Boon’s claim of acceleration of sea level rise. A change in relative sea level that is accelerating at 1 mm/yr/yr would show something like 2 mm rise this year, 2.1 mm next year, then 2.2 mm, then 2.3, then 2.4 — the annual rate would keep increasing by the amount of the acceleration. Imagine a ball rolling down an incline — it accelerates as it goes, moving faster each second,

      Boon claims that sea level rise, the annual change at Boston, is accelerating. In 2012 , the claimed at the end of the year 2011, Boston’s sea level was rising at an accelerating rate of 0.305 mm/yr/yr. So in 5 years, the annual rate in 2016 should be, if he is right, the rate of 2011 — 2.93 mm/yr, PLUS an additional 1.525 mm/yr (5 times 0.305) , which should result in an annual rate in 2016 of 4.455 mm/yr. Yet in 2016, the rate was only 3.065 mm/yr. The claimed acceleration did not actually take place.

      Relative Sea Level at Boston has risen by about 280 mm over the last 100 years — about 11 inches, which is well in line with generally accepted Global Sea Level rise over the same period — I gave the NOAA Tides and Currents chart for Boston in the essay. This graph shows a long steady, monotonic rise over 100 years, with no acceleration.”

      Boon’s calculated acceleration does not appear in the real world tide gauge record.

      I’m sure you are familiar with basic physics graphs of a ball rolling down an inclined plane — it accelerates, rolling faster at each subsequent time point. That’s what Boon claims for RSLR at Boston (used as my example). But the Tide Gauge data does not support Boon’s claims — the sea surface is not rising faster in 2019 (annual linear rate- his term) than in 2011 — thus there is no acceleration found.

      • Thanks for the reply but don’t address the text I quotes which was yours.

        I’m not saying these report cards are correct, they openly admit they chose the fitting period in order to get the result. But to do an effective rebuttal you cannot do so unless you understand the subject. Thinking tide gauge uncertainty can be compared directly to a value of acceleration in totally different units as you did here:

        for the mathematically inclined, the estimated error range for tide gauge monthly means (and thus the above annual trends as well) is 200 times the size of the reported acceleration for the Alameda tide station and more than 300 times of the acceleration for San Francisco.

        .. and by slapping the error bar on a graph of sea level rate and acceleration just attracts derision and gives the Waffen SS cross-dressers at SkS an easy target.

        Please get your work checked next time.

        • Greg ==> The SLR Annual Trends are created from the Monthly Trends…..which are presented as errorless….yet they must have uncertainty ranges attached to them. The Monthly Estimated Error Range for tide gauge records from NOAA gives us an idea of the error uncertainty ranges for all calculations made from Monthly Sea level means from tide gauges.

          My purpose for doing so was to give an idea of the uncertainty that must attach to such infinitesimal calculated Annual Acceleration rates.

          There is nothing whatever wrong with this concept.

          I would challenge Boon’s team, or yourself, to give a valid estimate of the uncertainty of either Boon’s Annual Linear Rate or the Annual Acceleration Rate — using NOAAs data on tide gauge error ranges — not just a mathematical concept of the uncertainty of the mean — but based on physical properties of the tide gauges themselves. (That’s why NOAA gives +/- 5 mm…..for monthly means.)

  20. Kip, some years ago I was told by a Fellow of the Royal Statistical Society that when extrapolating you needed ten points of back data for every future point. If your unit of time is one month then the extrapolations could be creditable; if it is one year then they are not.

    • Rules of Thumb can be useful. However, the reality is that any time series (or any arbitrary high-order polynomial function) can suddenly veer away from a smooth trend line. Consider the impact of the asteroid that killed the dinosaurs. There was a pulse of extreme heat causing fires, followed by perhaps two decades of extreme cold. The 10 months preceding the event would have been useless in extrapolating the next month. The 100 months preceding the event would have similarly been useless in extrapolating the 10 months following the impact.

  21. Kim
    May I add my pennies worth.
    Why do we get acceleration – because we use quadratic curve fitting.
    Why do we use quadratic curve fitting – (to mis-quote JFK) not because it’s hard but because it’s easy.
    As a Chief Design Engineer in charge of analysis of Nuclear power, Bridges, Offshore structures etc over many decades I always judged polynomial curve fitting as dangerous and polynomial curve extrapolation as criminal.
    In my paper https://drive.google.com/file/d/17lXnNtsLSlzSOx7tRvbDPwYMDibpvXKG/view?usp=sharing
    I showed that the residuals from the NASA levels (defined as the difference between actual measured values and the best fit straight line) could be followed just as well with a sinusoidal curve with a period of 22 years given by 3.5sin(((5+2t)/22) π) where t=0 at start of 1993.
    I then showed that if you generated a set of data using this sinusoidal equation and applied a quadratic curve fit to a 25 years set of results an acceleration of 0.09mm/year2 was obtained, very similar to the Nerem et al calculations in their 2018 paper.
    This shows the much higher accelerations (when compared with Tidal Gauge readings) they quoted is due mainly to the choice of starting date, namely 1993, when residuals were at a high positive.
    Applying a quadratic curve fit to the sinusoidal curve over longer and longer time periods up to 60 years shows the approach always indicates acceleration and only reaches values consistently below 0.01mm/year2 after 50 years eventually becoming asymptotic to zero.

    • Alan ==> Thank you for sharing your paper with me. I have emailed a question to you at your gmail address.

  22. I am interested in what your hometowns are doing in regards to sea level rise
    ======
    Nautical Charts add a datum block for GPS correction, so why do they not show a datum block for sea level rise?

    Billion of dollars and untold lives would be threatened by inaccurate charts. And the charts were drawn to an accuracy of 1 foot when they were first surveyed a couple of hundred years ago.

    So if sea level rise is real, why has it escaped the notice of the people that sail the oceans. The people who’s lives and livelihoods depend on knowing how much water they have under the keel.

    Are we looking at a true rise, or simply a long period oscillation? What determines the ocean height? Isn’t it the internal heat of the earth. Wouldn’t the oceans sink out of sight beneath the earths crust, except for a layer of high pressure steam, deep within the crust, powered by heat from the mantle.

    • ferdberple ==> I am a sailor — spent half of my adult life living at sea on boats and ships — The reason charts are not updated for SLR is that SLR is insignificant when compared to the tides at most locations.

      Ships need to n=know meters (or feet) of water below their keels — they really don’t care about the inches.

      Global SLR is believed to be about 8-12 inches over the last century.

      I have never risked by boat on a chart reading within 8 inches of danger — when on ships, we wouldn’t risk a bar unless we showed meters of extra water below the keel.

      • Kip “I have never risked by boat on a chart reading within 8 inches of danger — when on ships, we wouldn’t risk a bar unless we showed meters of extra water below the keel.”

        Aside from which, a bit MORE water under the keel is unlikely to be much of a concern to those on watercraft unless they are engaged in some almost certainly illegal activity that depends on the inability of bigger craft to follow/intercept them.

        • Don K ==> Very good point — I have never seen a chart depth record changed in my 50 years at sea….

  23. Sea floor spreading is reortedly 60 to 160 mm per year. Sea level rise is reportedly 3 mm per year.

    Seriously? The shape of the ocean basins is changing 20 to 50 times faster that the sea level itself is changing. And science attributes this to burning fossil fuels.

    Why not the “evil eye”. The number of people on earth is increasing along with sea level. More people, more witches. Thus witches are causing sea level rise.

  24. The graph listed under the caption “What’s Wrong With This Picture” shows the blue line going slightly downward over the last 6 years or so. How does anyone try to fit a concave-up (accelerating) parabola into a recent downward-sloping trend? Did the person who did this curve fit flunk Algebra II in high school?

    Occam’s Razor states that the simplest explanation is usually the best. In this case, the simplest explanation is a linear trendline, unless there is convincing statistical evidence of an acceleration, which is clearly lacking here.

    Then we need to consider the physical causes for a sea-level rise. If there is a heat imbalance between the heat received from the sun and that radiated back to space, any net glacial melt (melting during the warm season minus freezing during the cold season) would be equal to the heat imbalance divided by the heat of fusion of ice (a linear relationship), and thermal expansion of the oceans would be the additional heat absorbed by the ocean multiplied by the coefficient of expansion (again, a linear relationship). Unless the heat imbalance is itself accelerating, there is no physical reason why sea level rise would accelerate.

    If sea level rise may be a problem for some coastal cities, they may need to build a sea wall. The good news is that if sea level rise is not accelerating, they have a longer time to build a smaller sea wall.

    • Steve ==> We don’t have a very good grasp on physical causes for Global SLR, other than warming from the end of the Little Ice Age — the rest of the “contributors” add up if one squints their eyes a certain way but we don’t find those contributions in the Tide Gauge record.

  25. Epilogue:

    This has been an interesting post and an interesting Comment Section.

    Two readers have had serious objections to my annotation of Boon’s graphic titled “U.S. West Coast Sea-Level Trends and Processes”. The main beef is that I added on NOAA’s “Estimated Accuracy” for Aquatrak® (Air Acoustic sensor in protective well) Tide Gauges (the type currently in use at Boston, MA) which is, for Monthly Means, ± 0.005 m (± 5 mm). For your general information, the Estimated Accuracy for Individual Measurements is ± 0.02 m (± 2 cm).

    Compounding my alleged offense, I pointed out the relative magnitudes between Boon’s calculated “Rise/Fall Rate (mm/yr)” and Boon’s “Acceleration (mm/y2)” and NOAA’s Estimated Accuracy of the Monthly Means.

    Why did I do this? Simply because all long-term sea level calculations from tide gauges are built upon the basic building block of Tide Gauge Station Monthly Means. The Permanent Service for Mean Sea Level keeps this international record. NOAA keeps its own copies and forwards them to PSMSL. The great oddity of most sea level calculations is that they ignore the uncertainty of the original data.

    It is bluntly unscientific to calculate derivatives of original data and ignore that data’s uncertainty. The basic unit of all these sea level calculations is the Tide Gauge Station Record’s monthly mean — which comes with a known and acknowledged uncertainty of ± 5 mm.

    It would have been wrong for me to show Boon’s graphic without mentioning the dropped out uncertainty of the data from which they were derived.

    Not everyone will agree with my view on this — I accept that as a given.

    Thanks for reading.

    # # # # #

  26. By any rigorous mathematical definition, acceleration is the second derivative of a time-history. It is always a high-pass operation on the underlying continuous signal. In practice, we have only discrete-time series of sea level, which are necessarily low-passed to eliminate fluctuations due to sea and swell. Thus we dealing always with a BAND-passed signal, whose particular frequency response is seldom known explicitly–or even considered by those who are prone to opine. Small wonder that there’s no agreement as to whether sea-level rise is accelerating or not.

  27. Kip, If the trend is a quadratic, then I would imagine it has fallen from a higher point in the past too… so couldn’t we extrapolate it back to when we started emitting CO2 (the supposed cause of the change from a steady-state), and see how much higher the ocean was back then?

    • CommonA ==> There is no steady state for sea surface height. There is only the present (last few hundred years), relatively recent (centuries, millennia) , and distant past.

      CO2 concentrations do not cause sea level change. Big changes in energy retention by the Earth climate system could….and this explains the steady rise in sea surface height since the end of the Little Ice Age.

      • I’m just pointing out that their curve of best fit extrapolated backwards might provide a humorous and almost as ?compelling? reason why it is not a good choice… unless there is some reason why the back curve is invalid, so that they can legitimately use only the following upwards trend, and not the previous downward one?

  28. https://ars.els-cdn.com/content/image/1-s2.0-S027311772030034X-gr2_lrg.jpg

    https://www.sciencedirect.com/science/article/pii/S027311772030034X

    “Abstract
    … GMSL based on ESA data on the 1991–2019 period within ± 82° latitude exhibit an acceleration of 0.095 ± 0.009 mm/yr2. The corresponding value for the TPJ data is 0.080 ± 0.008 mm/yr2 for the 1993–2019 period and within ± 66° latitude. The ERS-1 satellite was launched shortly after the large Pinatubo eruption in 1991. The satellite observes a decrease of 6 mm in GMSL during the first 1.7 years until the launch of TOPEX/Poseidon. The distribution of sea level acceleration across the global ocean is highly similar between the ESA and TPJ dataset. In the Pacific Ocean regional sea level acceleration patterns seem related to the El-Niño Southern Oscillation (ENSO) whereas around Greenland a clear negative acceleration is seen.”

  29. Kip, I’ve been reading your series on sea level rise and am somewhat confused as to why the vertical land movement as measured by the CORS stations has to be factored in. I first came upon this idea of the land sinking or rising in my study of Great Lakes water levels. The Great Lakes watershed is subject to isostatic rebound, but its my understanding that all of the land in the watershed, including the lake bed, is rebounding.

    If the CORS station measures the vertical land movement, isn’t the sea bed also moving at the same rate? And if so then there is no reason to factor in the Vertical Land Movement as measured by the CORS stations.

    I understand of course that the piers where the tide gauges are mounted are sinking into the muck, but that seems to be independent of the Vertical Land Movement. Even if the land is rising, those piers are sinking!

    • Scott ==> I’ll try to explain. For any locality, the only important sea level is where the sea surface height hits the land — that is Relative Sea Level, But even for Relative Sea Level, it is important to know if the sea sruface height is really rising, or if the Tide Gauge (pier, dock) is sinking. It most cases, it is both — the tide gauge is sinking and the sea surface is rising. For the rest of the locality, the town let’s say, they want to know how fast the sea surface is rising compared to the town (not just the pier or dock). CGPS let’s them know that.

      For the GLOBAL or REGIONAL sea level, it is absolutely necessary to know how much of the measured change in sea surface height at the Tide Gauge is due to the TG sinking/subsiding.

      In some places, the continental mass is actually rising away from the center of the Earth. In other places, the continental mass is sinking towards the center of the Earth. All these movements are in single digit millimeters per year.

      The movement of the continental mass doesn’t move the ocean surface — imagine pushing a floating bowl down into the water (in a very large swimming pool).

      Continental land mass movement, up or down, changes where the sea surface hits the land. And that’s important.

      But then the oceans gain overall water mass, as long as the ocean basin volume remains the same, the the sea surface height will go “up” away fro the enter of the Earth.

      The sea bed may move in its own ways, including along with the continental land mass, but it is the water’s surface height against the land that matters. Moving the sea bed down doesn’t necessarily change the surface height (from the center of the Earth).

      This is where satellite sea surface height measurements come into play — we now know that the sea is not a bathtub — its surface is not evenly smooth — it is higher in some places than others — actually rising in some areas and getting lower in others.

      Email me at my first name at the domain i4.net if this still isn’t clear.

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