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“Acceleration” in Sea-Level Rise Found to Be False – An artifact of Switching Satellites

February 27, 2021

By Paul Homewood



From Climate Realism:


One of the most common arguments climate alarmists make is that rate of sea-level rise is “accelerating” or rising faster every year.

Sea-level data reported from satellites indicate seas are rising approximately of 3.3 mm/year (See Figure 1). By contrast, tidal stations have recorded a rise of approximately 1 to 2 mm annually, a rate which is little changed over the century or so for which we have adequate records. Indeed, as reported in Climate at a Glance: Sea Level Rise,  the oldest tide gauge in the USA, in New York City, shows no acceleration at all going back to 1850.

Why the large difference?

The answer it turns out is simple. When NASA and NOAA launched new satellites, the data they produced wasn’t the same as the data recorded by earlier satellites.

Figure 1. University of Colorado sea level data, showing the trend and acceleration. Note that the graph shows no overlap between the individual satellite records. SOURCE: UCSLR Group

Citizen scientist Willis Eschenbach obtained NOAA’s Excel spreadsheet showing the full dataset for each of the four satellites. He plotted the NOAA data. Unlike the Colorado data above, it included the full overlap between the individual satellites. He then looked at the rate of sea-level rise shown by each of the four satellites separately. Figure 2 shows that result.

Figure 2. NOAA sea level data, showing the trend of each of the full individual satellite records and the overall trend. SOURCE: NOAA Excel Spreadsheet

Full post here.

  1. Philip Mulholland permalink
    February 27, 2021 10:14 am

    Well the δLOD did always show that it was a false claim.
    Where exactly do these people do their science?

    • February 27, 2021 10:49 am

      On a computer model.

      • Mike Jackson permalink
        February 27, 2021 11:18 am

        ZX80 or Commodore 64?

      • Malcolm Skipper permalink
        February 27, 2021 11:58 am

        ZX Spectrum – it gives a wider range 😉

      • Duker permalink
        February 28, 2021 12:23 am

        Not a single model run , they found that produces ‘ridiculous results’, so they have server grade multi CPU processors which can do 100s or more runs of the model and then mix it all up with different models doing the same.
        The result is the proverbial dogs breakfast, but they plot a median result, hide the dogs breakfast results, and the world thinks its a nice steady increase which can be jacked up on demand.
        Even now if a researcher doesnt have data from previous years, no matter they can model ‘old data’ as well to look back 1000 years

  2. Gerry, England permalink
    February 27, 2021 11:02 am

    Has there ever been any changes to data or data recording that have not made the whole climate scam look worse than it is?

    In the real world the Northern Hemisphere snow pack is going off the scale as is the North American snow pack. And the number of daily, monthly and evah! cold records set in the US in the Arctic spell is astonishing, especially in the context of it supposedly getting evah warmer!

  3. February 27, 2021 11:50 am

    I have never been able to get to grips with the satellite measurement given issues of resolution. It seems to me that trend only is possible not absolute measurement given the total measurememt error. Remember the orbit fluvctuation issue?

    If we just stand back and consider shear volume of claims disinformation and hysteria around Trump and the total silence from most of the media on the shocking way that Biden is implementing seismic shifts in America is it any wonder that the same garbage is occurring vis a vis claims about climate?

    Even IF sea level rise is accelleration that speaks of an effect NOT a cause. Have you noticed that all of the worthless pathetic low grade research is on claimed effects? None of them go anywhere near the claimed cause except for treating it as proven ( it most certainly is not).

    Those running this show know that fools in the West are so easily led. Now that we employ brainwashed leftie idiots as teachers on both sides of the pond who embelish the already science free garbage about climate in “science class” with their own personal opinions we are well on the way to the edge of the cliff. I cite Texas as a case in point. Since when did intelligent people not understand the difference between guarranteed base load suppliers and virtue signalling toys?

    • dave permalink
      February 28, 2021 11:06 am


      My daughter-in-law teaches math at a large secondary school in a “nice” Home County.
      She is simply fed-up to the back teeth with the non-math cant she has to deliver every day. The exact topic is always a mere fad – which varies with the media obsession du jour, – and
      it is always mind-rottingly dogmatic stuff.

      At present, when the pupils ask her whether it is true, in her opinion, that they are all going to give lethal Covid-19 to their families the moment they leave their masks off, she simply says
      “My terms of employment do not me allow me to communicate my opinion of anything to you.”

      Incidentally, RSS are a month late with their analysis of satellite measurements. I emailed them politely and received an equally polite reply that they were having some “difficulties.” Um! Could that be because they are trying to magic away a seriously drooping metric?

      The Sun is about to go spotless again. It is getting to be a habit.

  4. Simon Derricutt permalink
    February 27, 2021 12:30 pm

    Jason 3 runs in a 1336km orbit, which I assume to be height above sea-level, and uses a radar to measure sea-level height. The accuracy is stated as +-3.3cm, which implies a timing accuracy to around a picosecond, and this will need to be corrected for atmospheric density which will affect the speed of light in the atmosphere. It also implies that the height of the satellite must be known to an even tighter limit, since the error in the satellite height and its distance from the sea surface will add together. If we assume the same error in both measurements, that implies a precision and accuracy of less than 1.7cm in 1336km or about 13ppb. That itself is quite a claim.

    The actual sea-level rise as measured on tide-gauges is around 1.8mm/year, or about 1/20th of the precision of the satellite measurement. Given the claimed accuracy and precision, the change is well below the threshold of measurement and thus you can’t make any estimate that there has been any change until the sea-level has changed by at least the accuracy claimed. Since the start of the measurements in 1993, the measured rise is only twice the accuracy in the most-recent measurements, and thus could be half that rise in truth. They should be stating that rise as being 90mm+-33mm, but Topex was claimed to have an accuracy of 4.2cm so really this should be 90mm+-42mm.

    It’s hard enough to measure sea-level accurately by dipping a ruler into it – there are waves and tides, after all. A radar measurement will give a return from the peaks and the troughs of the waves, and thus the return won’t be sharp but instead a spread-out signal where you need to decide at what points the signal is not there and where the peak is. Any drift in the amplifiers may be interpreted as a change in height. I just don’t see how it’s possible to claim an accuracy of even 3.3cm in that measurement, even if you average a load of readings. Yep, you can produce a figure from the measurements, but there is way too much uncertainty in the individual measurements to achieve the claimed accuracy. This number will of course depend on exactly how you do the statistical calculations.

    The actual tide-gauges will produce the most-accurate measurements relative to the bedrocks (which may themselves be rising or falling). The ground movements will likely have a more-stable change (any acceleration will be very small) thus allowing a better estimation of sea-level change.

    If the claimed accuracy is 33mm, you simply can’t claim a yearly change of 3mm or 4mm can be measured. That’s somewhat like trying to claim you can measure the difference in thickness between two blocks where one is 100.001mm and the other 100.002mm using a digital caliper with a precision of 0.01mm.

    • February 27, 2021 2:32 pm

      One may wonder if they have actually calibrated the radar by pinging known land elevations on successive passes. If they have not how do they know the altitude of the satellite at various points of the orbit, The sea is not a Mill Pond and waves and swells are never constant in amplitude so how can anyone have confidence of the real height down to millimeters . Land based tidal gauges, corrected for land sinking or rising,are the only true measurement. As for models – its GIGO (garbage in garbage out) and the new generations of supercomputers only means the garbage can be processed faster.

      • roger permalink
        February 27, 2021 2:54 pm

        Does not the air pressure also have a bearing? I ask only because the area beneath a hurricane often surges in height considerably we are told as the surge inundates the land as it comes ashore.
        Is this yet another unknown adding to the waves and swells ?

    • John Peter permalink
      February 27, 2021 4:08 pm

      I read the Willis Eschenbach article in Whatsupwiththat the other day and regretted that he did not furnish an up-to-date chart of global sea levels taken from tide-gauge measurements. I am not sure they exist now. I believe that they took tidal gauges up to the start of satellite measurements and then continued with the satellite measurements without indicating a breakpoint, thus generating an acceleration through splicing. A kind of Mann trick.
      Maybe Mr. Homewood can find one and add it to the article just for a visual comparison.

      • Adam Gallon permalink
        February 27, 2021 7:28 pm

        Tidal gauge data available here.

      • Duker permalink
        February 28, 2021 12:27 am

        The last time I looked some of the original tide data series , many had been ‘adjustocened’ up. ( Apart from any sinking/rising ground levels

    • Russ Wood permalink
      March 2, 2021 10:31 am

      Isn’t this the old “accuracy versus precision” problem? And I know that at least the tide gauge at Birkenhead, Merseyside has been going for about 200 years. I remember as a kid seeing the analog tidal predictor machine in the Bidston hill observatory!

      • Dave Andrews permalink
        March 3, 2021 5:36 pm

        I used to live on the Wirral and for a few months before I went to university I had a job in Liverpool. I went to work by bus and ferry every day. The tidal range in the Mersey estuary can be huge, over 9 metres is common.Not having access to computers smart phones in 1967 I never knew if I was going to have a steep walk down to the landing stage at Seacombe and an equally steep climb up the other side each morning or not. Either way by the time of my return ferry the both walks would be either flat or or steep depending what had happened earlier in the day.

  5. Ray Sanders permalink
    February 27, 2021 4:41 pm

    Meanwhile over at the Grauniad/Nobserver they have a article about a guy who knows all about producing bogus graphs. Just looking at his photo tells you what a…… he is.

  6. February 27, 2021 6:46 pm

    Thank you Paul – great info.

    PS – I noticed almost a week ago that NOAA’s site is not loading. Wonder if they are up to something?

  7. Jack Broughton permalink
    February 27, 2021 8:14 pm

    Looked at Adam Gallon’s link to NOAA. Very interesting spreadsheet and demonstration of how to manipulate statistics. NOAA list 375 stations to get an average sea level rise of 1.298 +/- 0.716 mm/year. This looks fairly convincing until one sees that over half of the stations started after1960, thus start from a cold part of the climatic cycle when ocean density was higher, as the world was heading for an ice age!

    If the stations which started reporting before 1960 only are considered the average rise rate is 1.13 mm /y.

    The newer sites (which even NOAA say is a dubious time frame) give a rise rate of 1.65 mm/y and distort the average rise rate. Any time frame below 30 years should be discounted as other than a local measurement.

  8. Vernon E permalink
    February 27, 2021 8:38 pm

    Simon (above) is spot on. There is no such thing as “sea level”. Tidal variations are constanrtly changing in height and time. There can be no questions of millimeters of accuracy. Maybe the only meaningful data for human occupancy of coastal regions is the trend of MWHS (Mean High Water Springs) and I heve seen no reference to the record of this anywhere, but in practical terms I don’t think there has been any discernible change since settlement began.

  9. Phoenix44 permalink
    February 27, 2021 10:05 pm

    Ironic that the Alarmists spend so much time adjusting past temperatures as if they have systematic error whfn they don’t then fail to notice a rather obvious case of systematic error and make no effort to adjust it.

    It’s almost as if they start with the result and fit the data to that.

    • February 28, 2021 7:02 am

      Your last point epitomizes the typical climate alarmists’ and bedazzled politicians’ faults, Phoenix44.
      You point up, in that sentence, one of most activists’ fundamental errors in scientific logic, i.e.,finding and selecting data which suit their preconceptions.
      Money-and /or status-seeking motivates such falsely conceived conclusions which are then expounded as objective scientific conclusions.
      Most of the politicians in charge of our affairs have fallen for such alarmists’ tendentious warnings on the predicted course of climate change.

      That is the root cause of the Western world’s present climate change shambolic policies.

      • dave permalink
        February 28, 2021 11:30 am

        Bien sur.

        Professional alarmists are simply in the position of the ancient Alchemists, who could never admit to themselves that their whole lives were a barren nonsense of chasing an absurd theory to the ends of the rainbow.

        And of course the ancient Alchemists were always looking for finance. One slightly more perspicacious prince in the Middle Ages asked such a fellow the obvious question. “Why are you asking me for gold if you already know how to make gold?” The equivalent question today is “Why are you trying so hard to convince me of something, which, if significant, would already be obvious?”

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