Guest essay by Eric Worrall
The United Nations has just warned the world that last year sea level rise hit an unprecedented 3.7mm.
Climate change is making the seas rise faster than ever, UN warns
28 March 2019
By Adam Vaughan
Sea levels across the world are rising faster than ever, the United Nations has warned, meaning we urgently need to increase action on climate change.
In a report released on Thursday, the World Meteorological Organization (WMO), a UN agency, painted a dire picture of all the key indicators of global warming.
The last four years were the warmest on record, concentrations of carbon dioxide in the atmosphere are at record levels and rising, and a global average sea level rise of 3.7 millimetres in 2018 outstripped the average annual increase over the past three decades.
The findings in the group’s annual State of the Climate report will bolster efforts by António Guterres, the UN secretary-general, to make governments commit to more ambitious carbon cuts at a landmark summit in September.
“There is no longer any time for delay,” wrote Guterres in a foreword to the report.
Last year was the fourth warmest on record, bringing the global temperature 1°C warmer on average than before the industrial revolution.
Read more: https://www.newscientist.com/article/2198091-climate-change-is-making-the-seas-rise-faster-than-ever-un-warns/
…
The WMO Press Release is available here, the actual report is available here.
Of course the report predicts more rapid sea level rise in the future. From page 16 of the report:
Over the period January 1993 to December 2018, the average rate of rise was 3.15 ± 0.3 mm yr-1, while the estimated acceleration was 0.1 mm yr-2.
Even if the UN estimate is correct, starting from 3.15mm per year this would result in a sea level rise of around:
d = vt + 0.5at2
d = 3.15 x 80 + 0.5 x 0.1 x 802
d = 572mm or just under 2ft of sea level rise by the end of the century.
I hope you all have your coastal evacuation plans ready. If this unprecedented rate of sea level rise per year continues, our children’s children might have to deal with 2ft of additional sea level by the end of this century. How will our grandchildren or great grandchildren cope with economic burden of constructing an extra foot or two of sea wall?
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In 150 years (or 300 years) what technological advancements will be available?
If we look back 200 years for a comparison, even assuming no acceleration into the future, what can we expect? It will be surprising.
I think nuclear exchanges and the advanced weaponry we read about are much bigger problems.
Michael Mann’s estimate of SLR by the end of the century:
https://youtu.be/HdoItL_xJLo
I’m not great with math but I think he’s outside the consensus here.
was that 6 to 8 feet or 68 feet?.. guess it don’t matter, either is enough to drown him in.
6 to 8 feet. A total of 2133mm. SLR would have to be 26mm per year for the 82 years from the time of that video to 2100 to get to 7 feet.
That will be the Statue of Liberty gone then….
I remain skeptical that they can even measure sea level that closely.
How about some reading?
https://www.aviso.altimetry.fr/fileadmin/documents/data/tools/hdbk_j1_gdr.pdf
Gawd, Bindidon, do you even read the references you post?
The specifications: +/- 4.2 cm, up to +/-5.2 cm at one standard deviation. The number of adjustments, including humidity, is mind-boggling. Guesses at 1 mm accuracy is beyond belief.
Lets change our society, economy and energy systems based on UN IPCC guesses about future changes to multiple climate metrics, including SLR.
Before reading documents such as this I try a quick series of searches to try to reveal how close to reality the observations will be. Revealing. Try “assum”, “approx”. “adjust” and then be astonished by the result for “correction”.
Bindidon
While a little out of date, it is an interesting document. It claims “Each measurement of sea level shall have an accuracy of +/-4.2 cm for the GDR products and 5.2 cm for the IGDR (1 standard deviation) over 1 second averages for typical oceanic conditions of 2 m significant wave height and 11dB sigma-naught. This error budget includes the altimeter noise, uncertainties in corrections of atmospheric path delays, sea-state related biases, and orbit error.” However, it also says, “It [DORIS] includes a dual beacon receiving capability and an on-board real time function … to compute the orbit ephemeris with an accuracy of 30 cm (1 standard deviation).” It seems to me that it is a stretch to get 4.2 cm SL accuracy when the orbital ephemeris only has an accuracy of 30 cm! Further, that ephemeris appears to be derived from land-based lasers, so the orbital behavior is less well constrained over the oceans, where there is no secondary calibration.
“Trust, but verify.”
Probably the source of the 3.7 mm sea level rise of 2018 is https://climate.nasa.gov/vital-signs/sea-level/. One can get the data of the graph. I made this picture of the sea level evolution from 2016 to 2018, based on these data.
http://users.skynet.be/fc298377/Climate_nasa_graph.gif
In the year 2016, the average sea level was 44.69 mm (my calculation). The max was 47.2, minimum was 42.16. Difference between max and min: 5.04 mm.
2017: average 46.09 mm; max 50.24; min 42.51; difference: 7.73 mm. The difference between average 2017 and 2016 was 1.4 mm. In 2017, there was a significant rise but also a remarkable decrease of the sea level.
2018: average 50.03 mm; max 53.77; min 47.03; difference: 6.74 mm. The difference between average 2018 and average 2017 was 3.93 mm, due to the almost steady rise during 2018.
But the average rise of the sea level in 2015 was 10.69 mm more than the average rise in 2014! So, 2018 is certainly not exceptional regarding the acceleration of the sea level rise.
In each case, we have to follow carefully the new data!
Rik Gheysens
Thank you / dank U wel / merci for the NASA link. I confess that I was too lazy to download the most recent sat data (U Colorado’sat series actually goes only till Jan 18).
Anyway, the goal was not for me to have a look at the last 12 sat months but rather to compare an own processing of the raw PSML gauge data with the entire sat period (I chosed the data column without GIA adjustment):
https://drive.google.com/file/d/1BwiiYbbACIwwmo4av9KiWrG02iVfbcho/view
The two series differ in linear estimate by 0.1 mm/yr. Sat data shows much more homogeneity (‘skeptic’s love to say the data has been ‘tortured’).
Of interest is moreover that while NASA publishes an estimate of 3.3 mm/yr, Office shows only 3.0 mm/yr.
This of course isn’t a reason to doubt about the correctness of NASA’s data: Excel’s and Libre Office’s estimate functions for example do not account for autocorrelation in time series, let alone would they accurately handle very short time intervals, which in most cases show much higher standard errors than longer ones.
Conversely, Church and White’s tide gauge analysis shows a higher estimate for 1993-2013 (3.6 mm/yr) than does PMSL.
This, again, is no reason to think that C&W’s analysis gives us an exaggerated estimate! The difference rather is that between simple layman’s work and decades of experience in the field.
The following résumé is of my, as yet unpublished, paper entitled “Accelerating Sea Level Rise – Reconciliation of Tidal Gauge Readings with Satellite Data” by Dr Alan K Welch FRAS FBIS. It summarises an investigation into the two large sources of historic sea levels, namely Tidal Gauge and NASA Satellite databases.
The summary of this paper, reproduced below, shows what was covered and the two graphs below are copies of Figures 8 and 22 from the paper with added explanatory annotation.
WARNING – The figures may not appear, as happened when I sent a similar comment to Climate Etc. Also if they appear the labels may be misplaced due to being a Word produced from the original Excel file. The formulae can easily be input to Excel to show the trends.
Summary
“The tidal gauge sea levels follow quite closely a constant accelerating curve. Closer analysis also shows that by combining this curve with a long-period (57 year) sinusoidal function many aspects of the tidal gauge data are even more accurately portrayed. A combined equation of the form
y = (0.0063×2 – 0.2452x + 174.82) + 6sin(((50+2t)/57) π)
was derived, where t is now defined as 1800 being t=0. See figure 8 and Appendix 2. This equation was then used for short and long-term projections. During this study other possible formulae to replace the constant acceleration were also investigated.
A separate study of the NASA satellite results was also carried out when the deviation from the linear regression line was used. This arrived at a similar short-term (22 year) sinusoidal variation resulting in a combined equation given by
(3.225x – 37.377) + 3.5sin(((5+2t)/22) π)
See figure 22. Short term projections were carried out.
The 2 periods of 57 years and 22 years could be related to known ocean oscillations.”
The first graph displays: –
– The average annual Tidal Gauge Readings (red dots)
– Best fit Quadratic Curve (dotted green line)
– Combined Curve (blue line)
The combined curve picks up the following features absent in the quadratic curve: –
– The low slope (0.5 mm/year) around 1920
– Two periods of increased acceleration around 1930 and 1990
– The almost constant slope (3mm/year) during the period of the Nasa Satellites
– Deacceleration periods around 1910 and 1970
– The start of a new deacceleration period
Main predictions are
1. Reduction of slope down to about 2mm/year by 2030.
2. Slope reaching 3.7mm/year around 2060.
3. Sea level about 250mm above 2018 levels by 2100.
It can also be concluded that the basic Quadratic Curve, being based on a nearly 140-year period, is probably a true indication of the process taking place and the limited extrapolation to 2100 is more acceptable than any based on the 25-year NASA Satellite readings. The Quadratic points to a constant acceleration, which in turn points to a constant “Driving Force” what ever that is, but to remain constant over such a long period of 140 years points, in my mind, to a mainly natural cause.
The second graph displays: –
– The NASA results (blue line)
– Best fit Straight Line (dotted green line)
– Combined Curve (red line)
The combined curve shows a better fit at each end than the equivalent quadratic fit. The latter would extrapolate to much higher values by 2100. The post 2018 extrapolation points to a reduction of the slope over the next 10 years but any further extrapolation is judged questionable at this stage as the long-term findings of the Tidal Gauges must also be taken in to account.
Each combined curve contains a sinusoidal element that may be the result of the methods used in obtaining the readings. The Tidal Gauge readings have a sparse coverage and would be affected by the known “60 Year” Oscillation. Allowing for all the various ocean amplitudes and phase differences could easily result in the +/-6mm perceived oscillation. The NASA readings do not have a 100% coverage and known 20 to 30-year ocean oscillations, such as the PDO, could easily lead to a +/-3.5mm added variation.
The main conclusions are that the Tidal Gauge results are a good indication of the changes in sea level. The additional sinusoidal variations are consequences of the method of measurement and coverage. This all points to a possible additional 250mm rise by 2100. If anyone is interested in viewing my paper, I can be contacted on alankwelch@gmail.com.
Alan Welch
There is a lot to write about your comment, but I’ll restrict it to your sentence:
“The additional sinusoidal variations are consequences of the method of measurement and coverage.”
My answer is that
– you can artificially construct a set of sine waves out of any curve;
– sinusoidal variations are above all a consequence of the method of evaluation.
Too many people consider time series spatially and temporally as homogeneous data sets.
That leads per se to ill-born evaluations despite a wonderful marriage of ‘accuracy’ and ‘precision’, because some regions and periods then become unduly overrepresented.
The most typical example is that of temperature measuring stations. Whichever record is chosen: about 50% of stations are in the US.
Not considering any spatial weighting automatically results in the Globe looking like the backyard of the United States.
My understanding is that the weightings are an attempt by the data-wranglers to account for that.
Dave “Fair” (?)
One of my teachers told me over 50 years ago:
“The more ignorant a person behaves, the more quickly s/he will be ready to discredit and denigrate other persons and their work.”
Be sure I’m proud to be named a “data-wrangler” by people like you.
Who are those being discredited and denigrated by my using a lighthearted shorthand for the various worldwide groups dealing with weather data?
Bindidn
Thank you for your comments
What you describe is Fourier Analysis and, yes, you can fit any set of waves as close as you require to get better and better fits.
But my approach was to use the best fit curve, in the case of the Tidal Gauges, a 140 year quadratic, and then look at the residuals between that and the actual results . This showed up a roughly 57 year cycle which I thought was significant. I didn’t take it any further.
The combined curve then revealed many significant features of the actual readings which my figure would have shown if only I could find away of adding to my comments.
Can anyone tell be how to add figures to these sort of comments?
Finally, as I indicated, I will E Mail (alankwelch@gmail.com) the full text to anyone so they can judge better if what I write is “a sinusoidal curve too far!” or has some significance.
Alan Welch
Thx 2u2
“Can anyone tell be how to add figures to these sort of comments?”
Simply add a link to them.
In earlier times, links ending with a picture file type were automatically expanded online; but actually, only a handful of ‘special guests’ enjoy this privilege.
I don’t see how you manage to detect any cycle within the data, the one over the whole period of course excepted.
Please upload your document and associated Excel stuff by using e.g. Google Drive like I do all the time.
Blididon
Thanks for your advice
Will try to add links to my paper (PDF) and 2 pictures via Google Drive
https://drive.google.com/file/d/1e89LBXsZAqAJfmAQb7wNXVpddKZK7j-y/view?usp=sharing
https://drive.google.com/file/d/1UfuXDp1-bxLC5rzw7gapSXRqhMuJTGx3/view?usp=sharing
https://drive.google.com/file/d/1vlFt1nPRREGsh_5qvYEunOLJoMBdIYqA/view?usp=sharing
As shown in the paper the 57 year cycle showed up in the residuals and judged by eye and was not via any mathematical curve fitting. As such it is indicative to a possible extra component of the Tidal Gauge readings as shown in the figure Appendix 2.
Likewise for the 22 year cycle for the NASA results. I admit this is less obvious but the approach was followed as a possible alternative to the Nerem et al quadratic fitting and subsequent extrapolation to 2100 which I think can not be justified with only 25 years worth of readings followed by over 80 years of extrapolation.
Please indicate if files picked up OK.
Again many thanks for your useful advice.
It says that the average over the satellite altimetry period (since 1993) is 3.15+/- 0.3 mm with an acceleration of 0.1mm/yr.sqrd
Their slr statement and some critical commentary appear in para#4 of this document.
https://tambonthongchai.com/2019/03/31/wmo/
Oops para#12
“The findings in the group’s annual State of the Climate report will bolster efforts by António Guterres, the UN secretary-general,”
___________________________________________________
Doesn’t the UN have problems enough with
– unsolved remains from Balkan wars
– Hutu / Tutsi drama Ruanda; Kongo; Uganda
– Baltic states fearing aggression from the east / high self-esteem: who is willing to waste time with the Baltic states neither able nor willing to pay their NATO dues
– unsolved malaria problems
– Ebola
– Biafra children starving to death since 60 years while their corrupt “statesman” have thick bank accounts overseas, not at least in the U.S. that contributes to that accounts
– etc.pp.
“Sea Level” referenced to what immobile standard, exactly? I’m honestly curious.
Everything on, in, and around the planet is constantly moving by inconsistent amounts, if I remember my geology properly.
What standard of reference could possibly be used to provide millimeter-level precision when measuring the average surface level of ~326 million cubic miles of water sloshing around in an unevenly-shaped ‘container’ of near-fractal boundary complexity, that is constantly changing shape in frankly immeasurable ways, with plate movements in the centimeters per year range?
I find it impossible to conceptualize such a measurement having any validity at that level of precision.
Can someone explain how it is possible to take this measurement without requiring assumptions many orders of magnitude greater than the reported result?