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New Paper Finds No Acceleration In Sea Level Rise

November 1, 2017

By Paul Homewood


h/t NotricksZone


I have long highlighted the fact sea level rise during the first part of the 20thC was just as high as now. In between, sea level rise slowed down considerably.

These sort of oscillations make it imperative that sea level trends are measured over much longer periods. Leading oceanographer, Bruce Douglas, often said that you needed to look at periods of 50 to 60 years.

In a new paper Parker and Ollier have analysed several large datasets of tidal gauge records, and conclude that sea levels have been oscillating about the same trend line during the last century and this century.




Long records of sea level show decadal and multi-decadal oscillations of synchronous and asynchronous phases, which cannot be detected in short-term records. Without incorporating these oscillations, it is impossible to make useful assessments of present global accelerations and reliable predictions of future changes of sea level. Furthermore, it is well known that local sea-level changes occur also because of local factors such as subsidence due to groundwater or oil extraction, or tectonic movements that may be either up or down.


Limited data from limited areas of study are, therefore, unsuitable for making predictions about the whole world sea level. Yet, people continue to make such predictions, often on an alarming scale. Here, we use one example to illustrate the problems associated with trying to make sea-level predictions based on a short record (25 years) in a limited region.


Linear and parabolic fittings of monthly average mean sea levels (MSL) of global as well as different local (United States Atlantic Coast, United States Pacific Coast) data sets of long tide gauge records.


It is clear from the analyses of the tide gauges of the “NOAA-120”, “US 39”, “PSMSL-162”, “Mitrovica-23”, “Holgate-9”, and “California-8” data sets and the United States Pacific and Atlantic coasts that the sea level has been oscillating about the same almost perfectly linear trend line all over the 20th century and the first 17 years of this century.


It is of paramount importance to discuss the proper way to assess the present acceleration of sea levels. This can not be done by focusing on the short-term upward oscillations in selected locations. The information from the tide gauges of the United States does not support any claim of rapidly changing ice mass in Greenland and Antarctica. The data only suggest the sea levels have been oscillating about the same trend line during the last century and this century.


This section of the paper is particularly revealing:



The loud divergence between sea-level reality and climate change theory—the climate models predict an accelerated sea-level rise driven by the anthropogenic CO2 emission—has been also evidenced in other works such as Boretti (2012a, b), Boretti and Watson (2012), Douglas (1992), Douglas and Peltier (2002), Fasullo et al. (2016), Jevrejeva et al. (2006), Holgate (2007), Houston and Dean (2011), Mörner 2010a, b, 2016), Mörner and Parker (2013), Scafetta (2014), Wenzel and Schröter (2010) and Wunsch et al. (2007) reporting on the recent lack of any detectable acceleration in the rate of sea-level rise. The minimum length requirement of 50–60 years to produce a realistic sea-level rate of rise is also discussed in other works such as Baart et al. (2012), Douglas (1995, 1997), Gervais (2016), Jevrejeva et al. (2008), Knudsen et al. (2011), Scafetta (2013a, b), Wenzel and Schröter (2014) and Woodworth (2011).

As an example of short-term measurement in a limited area, we consider the results of Davis and Vinogradova (2017). They consider time windows of only 25 years and only selected locations along the East Coast of North America. They neglect all other information in their selected locations and ignore results from other locations such as the West Coast of North America. Nevertheless, they draw global conclusions about sea level and the mass change in the ice of Greenland and Antarctica that per them has occurred since 1990.

Aim of this paper is to show that the information from the tide gauges of the USA and the rest of the world when considered globally and over time windows of not less than 80 years (but 120 years, or twice the quasi-60 years’ periodicity, work even better) does not support the notion of rapidly changing mass of ice in Greenland and Antarctica as claimed by Davis and Vinogradova (2017). The sea levels have been oscillating about a nearly perfectly linear trend since the start of the twentieth century with no sign of acceleration. There are only different phases of some oscillations moving from one location to another that do not represent any global acceleration.


In their Discussion, Parker and Ollier are even more scathing:

Davis and Vinogradova (2017) overrate the positive acceleration which they claim occurred after 1990 in one location by using a parabolic fitting of only 25 years of positive monthly average mean sea-level oscillations about the 60 years’ linear trend. They claim there was an acceleration of up to 0.3 mm/year2 after 1990. That is two orders of magnitude larger than the legitimate values. It is nothing but deceptive to infer global acceleration trends from short records while ignoring additional information from same tide gauges or tide gauges in other locations.

  1. November 1, 2017 12:03 pm

    Also, the assumption that accelerstion in and of itself is evidence of anthropogenic cause can be shown to be false. Please see

  2. Joe Public permalink
    November 1, 2017 12:03 pm

    Alarmists now have only their sorrows to drown.

  3. November 1, 2017 1:09 pm

    ‘the proper way to assess the present acceleration of sea levels’

    Sounds like assuming what you’re supposed to be investigating?

  4. November 1, 2017 1:10 pm

    Same story in Fiji and its region.

    “Previously, no study in the Fiji Islands had been devoted to the sea level changes of the last 500 years. No serious prediction can be made unless we have a good understanding of the sea level changes today and in the past centuries. Therefore, this study fills a gap, and provides real observational facts to assess the question of present sea level changes.

    There is a total absence of data supporting the notion of a present sea level rise; on the contrary all available facts indicate present sea level stability. On the centennial timescale, there was a +70 cm high level in the 16th and 17th centuries, a -50 cm low in the 18th century and a stability (with some oscillations) in the 19th, 20th and early 21st centuries. This is almost identical to the sea level change documented in the Maldives, Bangladesh and Goa (India).”

  5. Athelstan permalink
    November 1, 2017 1:35 pm

    On the one hand you have Nils Axel Morner a renowned expert on Neotectonics, Paleogeophysics and Geodynamics – telling us as regards SLs there is nothing to worry about.

    On the other hand we have such as algoracle telling the world about “NYC vulnerable to SL rises in terms of 6 or 7 Meters!” and yet he invests in beach front property in FL……………

    Hmm, who to believe?

  6. November 1, 2017 2:41 pm

    Reblogged this on Climate Collections.

  7. Broadlands permalink
    November 1, 2017 2:49 pm

    Does this mean that all of our added CO2 has not melted much frozen water?

  8. November 1, 2017 3:13 pm

    However did they manage to get this published in a reputable journal? I look forward to this being reported by the BBC – it’s not there yet!

    • HotScot permalink
      November 1, 2017 6:37 pm

      Ah! Good old Auntie.

      They will, of course, have to investigate it, analyse it, critique it, consider the likliehood and weight it up against all the other contributing factors before publica…………Wait, its the BBC! It’ll be out real soon embellished with some emotional shots of western cooling towers, Bangladesh cracked mud plains, and hurricane devastated palm trees in Florida.

  9. Curious George permalink
    November 1, 2017 3:20 pm

    Mathematically, the sea level rise acceleration is highly dubious. It is difficult enough to get a sea level rise signal, the first derivative of a very noisy sea level signal. Only climatologists claim any confidence in the second derivative.

    • HotScot permalink
      November 1, 2017 6:39 pm

      Curious George

      I wonder if Oceanographers get a look in? Or is it just that rare beast, someone with a qualification as a climatologist. Is there even such a thing?

  10. Chris Lynch permalink
    November 1, 2017 5:40 pm

    Guess who are not getting an invite to the Warmunist Christmas party?!!

  11. Stephen Rowden permalink
    November 1, 2017 5:42 pm

    Forgive me for a simplistic question. I read that “The data only suggest the sea levels have been oscillating about the same trend line during the last century and this century”. I understand and accept the concept of variations about a trend line. But is there agreement that the trend is of an increasing sea level? In simple terms what is the rate of increase in, say, the North Sea over the last 100 years or so.

    • November 1, 2017 6:49 pm

      They warn against using “naive” averages, but all their datasets come up with long term trends of between 0.86mm and 2.12mm/yr, which is around the sort of figures we are used to seeing, about 7 to 8 inches/C.

  12. mikewaite permalink
    November 1, 2017 8:02 pm

    I came across this recently which appears reassuring at least as judged from the abstract:

    From the abstract :
    -“European mean sea-level records are among the best time series data available globally by which to detect the presence of necessary accelerations forecast by physics-based projection models to elevate current rates of global sea-level rise (≈3 mm/y) to anywhere in the vicinity of 10–20 mm/y by 2100. The analysis in this paper is based on a recently developed analytical package titled “msltrend,” specifically designed to enhance estimates of trend, real-time velocity, and acceleration in the relative mean sea-level signal derived from long annual average ocean water level time series. Key findings are that at the 95% confidence level, no consistent or compelling evidence (yet) exists that recent rates of rise are higher or abnormal in the context of the historical records available across Europe, nor is there any evidence that geocentric rates of rise are above the global average.”-

  13. Geoff Sherrington permalink
    November 1, 2017 10:34 pm

    Must not forget the uncertainty from common assumptions. One that has long worried me is the assumption that the ocean floors are sufficiently without detectable movement affecting sea level. We have very sparse data on the geometry of the ocean floors. Yet we know that ocean floors do move and spread and create new islands.
    More positively, the present paper seems hard to argue against for its chosen time spans. Good. Geoff.

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