1 The global mean sea level reconstructions are untrustworthy
Many global mean sea level (GMSL) reconstructions have been previously proposed based on cherry picking the tide gage records of various record length and subsidence in a scattered and deficient data base to infer a GMSL rising over the twentieth century at a mean rate of +1.6 to +1.9 millimetres every year. This rate was estimated larger than the century before and subject to a continuous positive acceleration, and it is often compared with the recent satellite based computation of GMSL rated at +3.2 millimetres every year since 1993. As endeavours to account for this rate by summing similarly questionable estimations of individual contributions from ice melting and oceans warming still missed the mark in the period before 1990, Hay et al.  try to address this incongruence in between all inaccurate reconstructions without discussing the actual data that should support them.
Hay et al.  utilize probabilistic procedures and discover that the rate of GMSL rise from 1901 to 1990 is actually 1.2 ± 0.2 millimetres every year by accounting for the mass addition and thermal expansion contributions proposed in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Hay et al then show that the GMSL rose at a rate of 3.0 ±0.7 mm/year somewhere around 1993 and 2010 to conclude that the increment in rate with respect to the 1901–1990 pattern is larger than suspected and this discovery may obviously influence the projections of future ocean level rises towards even higher rates than the metre by 2100.
As in other tide gauge based reconstructions of the GMSL, the work by Hay et al.  fails to clarify what is the actual information available from the historical relative sea level records. Ocean level scientists frequently misconstrue and distort the tide gage records to demonstrate the IPCC expectations are right and it is unfortunately totally unclear to all the other researchers what is really available in terms of true measurements to back the IPCC sea level theories. As it is shown here, from what is really measured at the tide gages, the only scientific conclusion that may be drawn is that the few tide gages of enough quality and length along the world oceans and seas coastline are acceleration free over the last 20 years and rising on average of just +0.24 millimetres every year mm/year.
The inconsistency between the reconstructed GMSL that are continuously accelerating over the twentieth century and the actual measurements at the tide gauges has been noticed in many papers by the author and others (see [2–28] to name but a few). We recall here only as an example the works [2–15].
When all the world tide gauges of sufficient quality and length exhibit a pattern of slow rising acceleration free relative sea levels, any reconstruction proposing sharply accelerating sea levels following the carbon dioxide emission appear highly unrealistic. The steady sea level increment at the worldwide naïve average tide gauge of 3.6 millimetres over 15 years makes the claims of 1000 millimetres sea level rises by 2100 unreasonable.
The tide gages measure the ocean level motions in respect to the instrument. As the ocean level oscillates with numerous periodicities from hours to multi-decadal discovered, the established analysis of a tide gage result with the end goal of surveying the ocean level rate of rise (or fall) is to linearly fit the monthly average mean sea levels (MSL) time histories. As the longest periodicity caught in the tide gage signs is quasi-60 years in length, more than 60 years of information are needed to deduce an exact relative rate of rise at any tide gage. With less than 60 years of recorded information, the processed relative rates of rise are without doubt wrong, differing order of magnitude from the true values.
The most extensive database of ocean level information is given by the Permanent Service to Mean Sea Level (PSMSL). We will use here their latest data (see Table 1 in the appendix).
As the ocean level is supposed to rise and it is hence not any more a substantial reference point for vertical area positions, a novel satellite based framework is utilized to determine the vertical speed of GPS domes close-by the tide gages. This permits a first assessment of the subsidence (or isostasy) contribution to the relative ocean level rise (of fall). A standout amongst the most established computations of the vertical velocity of the GPS domes is proposed by the Système d’Observation du Niveau des Eaux Littorales (SONEL). We will use here also their latest data (see Table 2 in the appendix).
The evaluation of the vertical speeds of GPS domes still endure huge instabilities, just cover not very many years, sometimes as little as two, and is available for just a few locations adjacent to a tide gage. At long last, the subsidence of a waterfront tide gage may vary extensively from the subsidence of an inland GPS dome and the relative position of the GPS dome to the tide gage is usually not surveyed.
To comprehend the need of more than 60 years of recording to figure a reliable relative rate of rise of ocean levels at a tide gage, we show here the determination of the relative rate of rise by direct fitting in two tide gages of the Pacific, Sydney and San Diego, where the multi-decadal motions are not staged, the subsidence at the tide gage is different, and the begin of the record is different, Figure 1.
In one tide gage, the rate of rise is insignificantly increasing and in the other the rate of rise is barely diminishing throughout the most recent 20 years. The SLR20 is the relative rate of rise computed by utilizing a 20 years’ time window. The SLR60 is the relative rate of rise computed by utilizing a 60 years’ time window. The SLR is the relative rate of rise computed by using all the data available at any time.
The short time window is deluding in both areas, indicating relative rates of rise much larger or littler than the true values. Prior to 60 years of information are recorded the computed relative rate of rise is a long way from the genuine worth.
This figure shows how watchful we ought to be when managing short tide gauges even if precisely levelled against a datum, and regardless of the fact that accepting that the datum is settled when really it is definitely not that settled at all.
The vertical speed of the SONEL GPS dome adjacent the Sydney tide gage (SYDN) is −0.89 mm/year while the vertical speeds of the two SONEL GPS domes close-by the San Diego tide gage (PLO3 & PLO5) are −1.65 & −3.23 mm/year. In both cases the subsidence represents the most part of the relative ocean level rise.
Having cleared up the minimum length prerequisite, we should now consider the tide gages and GPS domes velocities computed in the PSMSL and SONEL data bases.
The geographical location of the PSMSL tide gauges relative rates of rise and their record length as well as of the SONEL GPS domes speeds give a scientific thought of which information is really accessible to compute a single parameter, the worldwide mean ocean level, since the 1900 or the 1870. How misleading is the cherry picking of the restricted subset of a very scattered and incomplete tide gages data base to stack together regardless of the difference length and subsidence is simple to understand.
The most recent PSMSL survey of relative mean ocean level fulfilling minimal quality necessities (yet not the 60 years of recorded information) can be downloaded from www.psmsl.org/items/patterns/trends.txt.
The study incorporate 560 tide gages, largest number of recorded years 183, smallest number of recorded years 21, average number of recorded information 56.52. While the greatest completeness is clearly 100%, the average completeness is 91.50% and the minimum completeness 70%.
The relative rates of rise computed in these 560 tide gages are variable from +9.72 mm/year to −17.42 mm/year with an average estimation of 1.04 mm/year, Figure 2. A positive relative rate of rise speaks to ocean levels that are rising versus the tide gage.
As the prerequisite of least 60 years of recorded information is very vital, a superior thought of the genuine rates of rise in any area might just take after thought of the stations fulfilling this last paradigm. For this situation, Figure 3, there are presently (2013) 170 tide gages to consider, of average number of years recorded 91.04, average completeness 93.72% and relative rates of rise running from +9.21 mm/year to −13.08 mm/year with an average estimation of 0.25 mm/year. Worth of notice, the statistical error of the fitting is ±0.15 mm/year, with the real inaccuracy anticipated that will be unquestionably much larger.
In the event that someone would be keen on processing the relative acceleration at the tide gage, for instance in the course of the most recent two decades, such a reckoning would oblige relative rates of rise constantly processed with least 60 years of recorded information, i.e. least 80 year recorded information at the present time.
By using the minimum 80 years of recorded information prerequisite, there are just 100 tide gages to consider around the world. For this situation, the average number of recorded years is 107 and the average completeness 95.13%, while the largest, smallest and average relative rate of rise of ocean levels are 6.56, −8.1 and 0.24 mm/year, Figure 4. As 20 years prior the relative rates of rise in the same tide gages were precisely the same the acceleration in these tide gages was zero in the course of the most recent two decades.
The world sea coverage is minimal over the last two decades, and vanishingly small going back in time. The number of tide gauges of effective length exceeding 100 years is only 53, those of length exceeding 120 years are 23, those of length exceeding 140 years 14, and those of length exceeding 160 years only 5. Only two tide gauges of enough length are available for the whole world since 1900. Therefore, the information supporting the global warming driven accelerating sea levels is the measurements never collected but only guessed in compliance to the climate models simulations.
Most of the long-record tide gauges are located in Europe and North America with other areas almost uncovered at present. With only 2 tide gauges satisfying the minimum length requirements in the year 1900 and 100 tide satisfying this requirement in 1993, the GMSL estimations since 1900 are pure philosophical hypothesis, without experimental confirmation. The estimations since 1870 are even more pure speculations.
Figure 5 presents the classical determination of the relative rate of rise by linear fitting in two of the oldest tide gauges of North Europe, Massluis and Wismar2, with different subsidence but about same multi-decadal oscillation and length. In both tide gauges, the rate of rise is about constant over the full century.
Massluis and Wismar2 are two of the only five tide gauges of the world in the PSMSL data base that may be used to study the sea level behaviour over the last 100 years, while Sydney and San Diego are other two of the only 53 tide gauges that may be used to study the sea level acceleration since 1950.However, the proposed pattern are generalised to all the other long term tide gauges of the different groups that may be sorted out. No sign of any acceleration is detectable since 1950, only minor changes, in positive or negative within then uncertainty range of the assessment, that are completely incompatible with the metre of sea level rise by 2100 claimed by the IPCC narrative.
If the rates of rise do not increase in all the location where enough data are collected to infer trends, there is no scientific evidence that the sea levels are accelerating. The only measurements that support the IPCC narrative on sea levels are only either those never collected or those completely misinterpreted.
If we do consider the vertical speeds of SONEL GPS domes downloaded from www.sonel.org/IMG/txt/ulr5_vertical_velocities-2.txtthese inland GPS domes pretty much near to tide gage areas just give a harsh thought of the unequivocally variable subsidence rates around the globe. We are speaking here about the land and not the ocean long term motion. The vertical speeds of the land are similar in size and variability to the vertical speeds of the ocean level.
The processing of the GPS domes’ vertical speed still suffers of huge inaccuracies, and the vertical speed of a coastal tide gage may vary extensively from the speed of an inland GPS dome, frequently introducing more subsidence.
In the 360 GPS domes considered, Figure 6, the vertical speed is 12.47 mm/year largest, −8 mm/year smaller and +0.44 mm/year average. A positive vertical speed speaks to the GPS dome is rising (i.e. isostasy). The average statistical fitting error is ±0.36 mm/year, with the actual inaccuracy confessed to be much larger at about ±2mm/year.
As the main goal of sea level monitoring is to assess the opportunity for the relative sea level to reach dangerous levels along a significant portion of the coastline, there is no need to consider inaccurate absolute sea level velocities to defocus from the fact the naïve averaging returns small relative rates of rises absolutely not accelerating.
Clear observational facts indicate that the sea level is not rising in the Maldives, Bangladesh, Tuvalu, Vanuatu, French Guyana and Suriname [21–23, 26–28], all key-sites in the sea level debate where terrible flooding scenarios have already been predicted to occur but where the sea level has been conversely fairly stable. The sea level record from Venice also serves as a simple further test for contribution to sea level rise by thermal expansion or mass addition, as subtracting the known subsidence there is no further sea level rise and no acceleration whatsoever in the last decades [21, 23]. Finally, both the satellite altimeter and the satellite gravity meter experiments actually returned stable global mean sea level signals turned to sharply rising only by arbitrary corrections [15, 28].
What the PSMSL and SONEL data bases tell us is that the estimations of the worldwide mean ocean level by Hay et al. since 1870 are pure speculation not supported by sufficient data.
The SONEL data base shows a significant variability of the rate of subsidence or uplift of inland GPS domes. The 326 GPS domes have uplift velocities ranging from+12.47 to −8.00 mm/year, with an average of +0.44 mm/year. The accuracy of this result is much larger than the ±0.36 mm/year only accounting for the fitting inaccuracy and very likely about ± 2 mm/year. The vertical velocity of inland GPS domes is not the vertical velocity of a nearby tide gauge that may suffer more subsidence for example for compaction.
The PSMSL data base for the relative rates of rise sea level vs. tide gauge is the most relevant information to understand global sea levels. The worldwide coverage is extremely scattered, with the most part of the installation located in the Northern Hemisphere in a limited range of latitudes covering reasonably well only Europe and North America. The 60 years minimum recording to infer realistic trends further reduces this coverage. The 560 tide gauges of the latest survey have relative rates of rise ranging from +9.72 to −17.42 mm/year with an average of +1.04 mm/year. These tide gauges have effective record lengths ranging from183 to 21 years with an average of 56.5 years. By considering only the tide gauges with more than 80 years of records, the 100 tide gauges have relative rates of rise ranging from +6.56 to -8.1 mm/year with an average of +0.24 mm/year. These values remained practically unchanged over the last two decades indicating the lack of any acceleration.
The tide gauges with sufficiently long records show that sea level is simply oscillating. Regretfully, one more paper is selling as experimental evidence what is actually pure philosophical speculation of cherry picked subsets of scattered information that once properly analysed tell us a completely different story.
A. Parker, Natural oscillations and trends in long-term tide gauge records from the Pacific, Pattern Recogn. Phys., 2013, Volume 1, pp. 1–13.Google Scholar
A. Parker, M. Saad Saleem and M. Lawson, Sea-Level Trend Analysis for Coastal Management, Ocean and Coastal Management. Ocean & Coastal Management, 2013, Volume 73, March, pp. 63–81.Google Scholar
A. Parker, Reply to Comment on Sea-Level Trend Analysis for Coastal Management by A. Parker, M. Saad Saleem, M. Lawson, Ocean & Coastal Management, 2014, Volume 87, January 2014, pp. 116–118.Google Scholar
A. Parker, The non-linear, naturally oscillating pattern of sealevels in the Chesapeake Bay, East Coast, USA, Nonlinear Engineering, 2013, Volume 2, Issue 1-2, pp. 1–10.Google Scholar
A. Parker, A realistic lower bound to the 2050 sea-level rise, International Journal of Ocean and Climate Systems, 2013, Volume 4, Number 3, pp. 197–211.Google Scholar
A. Parker, Reply to: "Comment on ‘Lower Bounds to Future Sea-Level Rise", International Journal of Ocean and Climate Systems, 2014, Volume 5, Number 1, March, pp.35–38.Google Scholar
A. Parker, Apparent hot and cold spots of acceleration along the Atlantic and Pacific coasts of the United States, Nonlinear Engineering, 2013, Volume 3, Issue 1, pp. 51–56.Google Scholar
A. Parker, Minimum 60 years of recording are needed to compute the sea level rate of rise in the western south Pacific, Nonlinear Engineering, 2013, Volume 3, Issue 1, pp. 1–10.Google Scholar
A. Parker, Impacts of sea level rise on coastal planning in Norway, Ocean Engineering, 2014, Volume 78, 1 March, pp. 124– 130.Google Scholar
A. Parker, Confirming the lack of any sea level acceleration around the Australian coastline, Nonlinear Engineering Nonlinear Engineering, 2013, Volume 3, Issue 2, pp. 99–105.Google Scholar
A. Parker, Discussion of a semi-empirical approach to projecting future sea-level rise, Nonlinear Engineering, 2014, Volume 3, Issue 3, pp. 149–153.Google Scholar
A. Parker, Present contributions to sea level rise by thermal expansion and ice melting and implication on coastal management, Ocean and Coastal Management, 2014, Volume 98, September, pp. 202–211.Web of ScienceGoogle Scholar
A. Parker, Persisting problems affecting the reliability of the satellite altimeter based Global Mean Sea Level computation, Pattern Recognition in Physics, 2014, Volume 02, Issue 02, pp. 65–74. Google Scholar
N.-A. Mörner, Eustatic changes during the last 300 years, Palaeogeogr. Palaeoclim. Palaeoecol., 1973, Vol. 13, pp. 1–14.Google Scholar
N.-A. Mörner, Earth rotation, ocean circulation and paleoclimate, GeoJournal, 1995, Vol. 37, No. 4, pp. 419–430.Google Scholar
N.-A. Mörner, Sea Level Variability, Z. Geomorphology N.S., 1996, Vol. 102, pp. 223–232.Google Scholar
N.-A. Mörner, Estimating future sea level changes, Global Planet. Change, 2004, Vol. 40, pp. 49–54.Google Scholar
N.-A. Mörner, Sea level changes and crustal movements with special aspects on the Mediterranean, Z. Geomorph. N.F., 2005, Suppl. Vol. 137, pp. 91–102.Google Scholar
N.-A. Mörner, The Sun rules climate. There’s no danger of global sea level rise, 21st Century, Fall 2007, pp. 31–34. Google Scholar
N.-A. Mörner, Sea Level Changes and Tsunamis. Environmental Stress and Migration over the Seas, Internationales Asienforum, 2007, Vol. 38, pp. 353–374.Google Scholar
N.-A. Mörner, The Greatest Lie Ever Told, P&G-print, 2007, (2nd edition 2009, 3rd edition 2010). Google Scholar
N.-A. Mörner, Comments, Global Planet. Change, 2008, Vol. 62, pp. 219–220.Google Scholar
N.-A. Mörner, Open letter to the President of the Maldives, New Concepts in Global Tectonics Newsletter, 2009, No. 53, pp. 80–83.Google Scholar
N.-A. Mörner, Sea level changes in Bangladesh. New observational facts, Energy and Environment, 2010, Vol. 21, No. 3, pp. 249–263. Google Scholar
N.-A. Mörner, Some problems in the reconstruction of mean sea level and its changes with time, Quaternary International, 2010, Vol. 221, pp. 3–8.Google Scholar
N.-A. Mörner, There Is No Alarming Sea Level Rise!, 21st Century, Winter 2010, pp. 12–22. Google Scholar
About the article
Published Online: 2016-03-12
Published in Print: 2016-03-01