Sea Level: Rise and Fall – Slowing Down to Speed Up

Guest Essay by Kip Hansen – 3 May 2022

Yes, I do know that acceleration, technically, means just a change in velocity.  But, in every day English, we use acceleration to mean an increase in velocity – speeding up — and deceleration as a decrease in velocity – slowing down.  I mention acceleration and deceleration because one of the major talking points of IPCC reported findings about sea level rise, the incessant media mantra, is that “Sea Level Rise is Accelerating”.  (here, here, here, here, here and hundreds more here)

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

LONG ESSAY ALERT: With apologies, this essay is for those who are interested in sea level rise and the question:  Is sea level rise accelerating?   It takes a lot of words and illustrations to explain the true situation.  Those with limited time can just accept this simple answer and move on: 

“Probably not at all, just maybe a wee tiny little bit that will not make any difference over the next century or two.”

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Is sea level rising?  Yes, of course it is.  It has been rising since about 1750-1775, coinciding with the end of the Little Ice Age.  This is widely accepted as shown below:

How do we know?  The important aspect of sea level is how it affects the land at the edges of the oceans.  The water level there is measure by tide gauges at the ports and harbors of the world.  The levels recorded by tide gauges are of local Relative Sea Level (RSL) – the level at which the sea surface hits the land.  This measurement includes both the actual rise in the sea surface height (think: distance from the center of the Earth) plus any vertical movement (VLM) of the tide gauge itself, either up or down.  In many locations the land mass itself is subsiding (sinking) due to glacial isostatic adjustment (GIA) as the land mass readjusts itself for the melting of the glaciers of the last great  Ice Age and at most tide gauge locations, the structure to which the tide gauge itself is attached, such as a pier or dock or sea wall, is also itself subsiding due to compaction of the soil underneath and the fact that many such locations are built on man-made filled substrate.  To see if sea level is rising, it is only necessary to look at high quality tide gauge records for whom the VLM is known to be relatively constant.  The linearity of these graphs is typical, there are many, many more. This image of the records of some such tide gauges:

Sea level is rising all around the world but at different rates as shown by the slopes of the trends.  Why?  NOAA says: “The graphs give an indication of the differing rates of vertical land motion, given that the absolute global sea level rise is believed to be 1.7 +/- 0.3 millimeters/year during the 20th century.”

As you can see, each of these long-term graphs have trends that are linear, that can be represented as straight lines, despite the wide amount of inter-annual variation.   None of them swoop up or swoop down, accelerating or decelerating on the century time scale. 

This is clear as shown in long-term tide gauge records at the PSMSL. If sea level rise was accelerating, it we would see it in these graphs.  But we do not.   Why then does the IPCC and the media go on and on about Sea Level Rise (SLR) Acceleration?

Boon and Nerem (and here).  Both of these accomplished scientists have been publishing paper after paper (Nerem here, Boon here) claiming they have detected the sea level rise acceleration that we do not see in the tide gauge records.

I have discussed Boon and VIMS  in the past.  SEA LEVEL: Rise and Fall – Part 5: Bending the Trend.

 I have written about the efforts of R. Steven Nerem at CIRES (Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder) and a major player at their Sea Level Group.  Nerem is convinced that sea level rise must be accelerating.  He has written papers and presentations and mostly convinced the IPCC and policy makers that that acceleration (by which he means sea level is rising faster and faster) it actually taking place in the real world in which we live and breathe.

Before we go on, readers should be aware of the potential bias in all of Nerem’s work:

BIAS WARNING:  You should know that Nerem is one of the contributing author’s to this WaPo, May 2016,  piece “10 things you should know about sea level rise and how bad it could be”, in which it is blandly stated “Scientists estimate that if it warms by about 4 to 5 degrees Celsius (7.2 to 9 degrees Fahrenheit), which is projected to happen by the end of the century if we don’t act on climate change, then all the ice will eventually melt. That’s 230 feet of sea level rise.” —– You should consider this whenever you see anything about sea level out of the Sea Level Research Group @ the University of Colorado — their blog actually contains a link to this newspaper article, as if it were a scientific paper or something to be proud of.

My previous work on Nerem and the Sea Level Research Group:

SEA LEVEL: Rise and Fall – Part 3 – Computational Hubris

SEA LEVEL: Rise and Fall – Part 4 – Getting a Rise Out of Nothing

SEA LEVEL: Rise and Fall – Part 4a – Getting Even More of a Rise Out of Nothing

Now, Nerem et al. have been at it again – still beating the sea level rise acceleration drum, but now with a longer data set and a much weaker position.  As of today, the full paper is available as “Extrapolating Empirical Models of Satellite-Observed Global Mean Sea Level to Estimate Future Sea Level Change by R. S. Nerem, T. Frederikse, B. D. Hamlington.  

From their abstract:

“We estimate a quadratic model of climate-driven global mean sea level (GMSL) change based on the satellite altimetry record (1993–2020), including a rigorous assessment of the errors in the quadratic coefficients. We then extrapolate this model 30 years into the future to 2050 and compute the 90% confidence interval. We find GMSL rise in 2050 relative to 2020 will be 16.4 cm higher, with an uncertainty range of 11.3–21.4 cm…..”  (11.3 cm = 113 mm or  ~ 4.45 inch :  21.4 cm =  214 mm or ~  8.4 in)

First, let’s be clear, Nerem et al.’s paper does not find anything.  No one can find something/anything in or about the future.  What their paper does do is it extrapolates a rise in sea level of 16.4 cm or 6.45 inches by 2050, now 28 years away, through a model primed with the concept of a quadratic curve of acceleration that they believe exists in the current sea level data.   

As of today, NOAA shows a sea level rise rate of 3.0 ± 0.4 mm/yr.   The slope trace (black) is on the original.  This is lower than that claimed by NASA’s on their special sea level rise page of 3.4 mm/yr in the next image:

Both of the above images, from data up to the same day, are based on the same data set from the same satellite missions.  The difference in 30 year trend – over 10% –   is the based on methods of adjustments for the variables as Nerem stated in an earlier paper: “Satellite altimetry is somewhat unique in that many adjustments must be made to the raw range measurements to account for atmospheric delays (ionosphere, troposphere), ocean tides, variations in wave height (which can bias how the altimeter measures sea level), and a variety of other effects. In addition, the sea level measurements can be affected by the method used to process the altimeter waveforms, and by the techniques and data used to compute the orbit of the satellite.”

The above graph from NASA shows a minor downward shift in SLR in about 2006 through 2015, but the sub-set of data has the same slope (trend) as the entire set. The NASA shows no curve, no acceleration.   For details on Nerem‘s previous SLR acceleration claims, see my three essays linked above.

Here is the money plot from Nerem et al. (2022):

Nerem et al.  attempt to support this projection with a back-projection that they claim matches the historical record:

In this graphic, the orange trace and shading is the observed SLR from Frederikse (2020).  Note that Frederikse is a co-author on Nerem (2022). Nerem starts his curve with his previously speculated curve in the satellite data and extends it back over Frederikse’s “tide gauge record”.

Ignoring the fact that Nerem’s quadratic fit back in time shows that sea level should have continued to rise into the past (prior to 1965) as his curving quadratic trend then begins rising, what is most obvious is that Nerem uses the slow-down in sea level rise to create an acceleration. 

There is one major feature of Nerem’s Figure 4 that is not mentioned in the caption or the text of the paper.  It is the most prominent feature of the graph and yet Nerem is silent on what it might be or what it means. He is even silent after I wrote him by email and politely asked about it.  Can you pick it out?

Yes! The giant grey shaded triangular feature.  Such a shaded area is normally used to represent uncertainty in data or a projection.  The only mention of what the grey area might be is this: “Figure 4 shows the results of the extrapolation backwards in time prior to 1993 compared to the tide gauge GMSL record. Although the errors on the extrapolation are large, the differences with the tide gauge record have a standard deviation of only 5 mm. Since our quadratic model performs well for the period 1960–1993, it can reasonably be expected to perform similarly for the next 30 years.” 

Saying that “the errors on the extrapolation are large” is an historic-scale understatement.  The error range in the backwards projection  from 2022 back to 1960 is larger than the entire illustrated sea level rise over the same period.  The extrapolation basically means “the sea level could have been anything over a more-than 150 mm range” – totally, utterly worthless. 

[ASIDE:  I will admit, that when I first read this paper, and page-downed to the page containing the graph, I literally laughed out loud.]

Now, let’s look at the real full record from Frederikse 2020 (used as the orange trace and shaded area in Nerem’s Fig. 4 above):

The Frederikse data is not the real observed global sea level from tide gauges, but is a reconstruction.  But we will let that stand, as no one can determine global sea level, rise or fall or rate, from tide gauge data. 

Looking at only the blue trace, and its shaded area, labelled observed SLR, we see sea level rising from 1900 to about 1960, when the rise obviously slows, becoming nearly flat. Note as well that in 1940, the claimed uncertainty is about ±20 mm and then reduces to about ±10 mm in 2021 – both of which may be off by an entire order of magnitude (reference my earlier essays linked at the beginning).    Then, around 1980, sea level rise begins to regain its prior rate.  Nerem uses this slow-down to create the illusion of an acceleration curve that extends up into the satellite data.  But, the satellite record, original data directly from JPL and NASA, contains no curve:

This next graph is directly from the published data set of the 10-day data points from each of the Topex/Jason satellite missions as of April 29, 2022:

Both graphs show the decade-long slow-down, 2006-2015, and then a return to the linear trend of the 1990s.

Here is the money question, from a climate pragmatist viewpoint:

If neither the satellite altimetry record of sea level rise or the best tide gauge records around the world show any acceleration in the rate of sea level rise… the reported Sea Level Rise Acceleration just a construct of biased interpretation of the data?

To get Nerem’s 16.4 cm by 2050,  sea level would have to rise at  5.47 mm/yr for the next 28 years —  almost twice the rate of today.  For Nerem’s higher extrapolation, 21.4 cm by 2050, sea level would have to rise at 7.13 mm/yr. 

As of the latest data from the Jason-3 satellite mission, sea level rise is continuing its long-term linear trend of about 3 mm/yr, with no acceleration as of yet. 

For those interested, Nerem et al. give a Kipling-esque ‘Just So story’ on how it could be that sea level rise is accelerating in their paper, starting on page 5 with the sentence “The process-based argument for using a quadratic model is as follows….”  .

Even at their most enthusiastic, Nerem et al. have sea level rise acceleration at 0.1 mm/yr2

Bottom Lines:

1.  Globally sea level is rising.  It has been rising since the end of the Little Ice Age and will continue to do so unless there is a major change in the planetary climate leading to another similar cold period.

2.  There is no good, sufficient or convincing evidence that global sea level rise is accelerating – there is only hypothesis and speculation.  Computation is not evidence and unless the results can be practically viewed and measured in the physical world, such results must not be presented as such.

3.  It is not scientifically legitimate to splice tide gauge records to satellite records – ever – as they measure different physical things.  As the tide gauge record extends to the present and continues to improve in quality, it should stand alone.   Tide gauge records apply only to the locality of the tide gauge and its Relative Sea Level.

4.  The global tide gauge record is quantitatively problematic, but individual records can be shown as qualitative evidence for a lack of sea level rise acceleration.

5.  Sea level and sea level rise are part of the modern scientific controversy generally known as Global Warming or, more recently,  Climate Change.  Most facts presented in discussions on all sides of the issues involved are more than likely to be opinions and, as always, opinions vary.  Wildly. 

6.  Only actually measured, validated raw data can be trusted and even then, you have to really understand what has been measured, exactly, and how it has been measured.  One such example is the original data record of your local tide gauge – unadjusted, untampered-with, un-averaged. 

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Author’s Comment

This field-wide effort to convince the world that sea level rise is accelerating is very destructive.  Localities on sea shores are being forced to try to plan and prepare for frightening sea levels that will not be seen for centuries, if ever.

The situation could be likened to civil engineers of 1900 being forced to plan their streets and highways to accommodate the speeds and sizes of today’s high-powered automobiles and tandem tractor trailers. The difference being that today’s cars and trucks actually materialized, while the scary IPCC-projected RCP8.5 sea levels never will.

Thanks for reading.

# # # # #

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May 3, 2022 6:10 am

Sea level rise. Pffffft! Another false bunch of quasi-science in attempt to instill fear in the masses of a doomsday which will probably never appear.
The planet is in control and will continue to do whatever with or without the help of us puny human beans. Ya think they’d have learned by now that all their predictions have borne no fruit, therefore they are dealing from a false premise and need to rethink(if they think at all) their approach to life.
I welcome the day when all the false climate prophets are forced to accept real jobs. I know the fast food industry is hiring right now, along with local 7-Elevens.

Gordon A. Dressler
Reply to  Kip Hansen
May 3, 2022 7:20 am

Miami (certain sections thereof that make the alarmist news, that is) is suffering from relative sea level rise . . . and those sections having the worst RSL have been scientifically linked to definite land subsidence.

“In this study we evaluate the contribution of land subsidence to the increasing flooding hazard in Miami Beach using Interferometric Synthetic Aperture Radar (InSAR) observations.  
“Preliminary InSAR results detected localized subsidence, up to -3 mm/yr, mainly in reclaimed land located along the western side of Miami Beach.  
“Although the detected subsidence velocities are quite low, their effect on the flooding hazard is significant, because houses originally built on higher ground have subsided since the city was built, about 80 years ago, by 16-24 cm down to flooding hazard zones.”
— Simone Fiaschi, Department of Geosciences, University of Padua, Padua, Italy, and Shimon Wdowinski, RSMAS, University of Miami, Miami, USA 

“Geological changes along the East Coast are causing land to sink along the seaboard.
“New research using GPS and prehistoric data has shown that nearly the entire coast is affected, from Massachusetts to Florida and parts of Maine.
“The study, published this month in Geophysical Research Letters, outlines a hot spot from Delaware and Maryland into northern North Carolina where the effects of groundwater pumping are compounding the sinking effects of natural processes.”
—John Upton, “Sinking Atlantic Coastline Meets Rapidly Rising Seas”, Scientific American, 14 April 2016 

As Kip has made clear in his article above, things are not always as they seem to be on the surface (pardon the pun).

And land subsidence has not YET been asserted to be caused by climate change 😉

Frank from NoVA
Reply to  Kip Hansen
May 3, 2022 7:59 am

‘Miami developers cut canals so that homes have the sea in their backyards..’

True, but the canal cuttings are used as fill to raise the level of their homes / yards.

Reply to  Kip Hansen
May 3, 2022 3:04 pm

I don’t know about Miami in particular, but sometimes those settlement crack are not so little

Reply to  Kip Hansen
May 3, 2022 4:58 pm

Prices of Miami waterfront homes keep going up.
There must be complex thought processes going on in the mind of people who buy multi million dollar waterfront homes. I don’t think SLR dominates these thought processes.

Reply to  RevJay4
May 3, 2022 6:53 am

9 out of 10 conclusions based on statistical analysis are wrong.

Reply to  Scissor
May 3, 2022 8:38 am

50% of the time 😉

Dave Fair
Reply to  Derg
May 3, 2022 1:25 pm

All statistics are 50%: Either something happens or it doesn’t.

Reply to  Dave Fair
May 3, 2022 3:50 pm

It was a naked gun joke.

Dave Fair
Reply to  Derg
May 3, 2022 5:04 pm

No criticism implied, Derg. My wife hates it when I, rarely, watch one. Watching OJ get beat up is a treat.

Tom Halla
May 3, 2022 6:20 am

This looks like an artifact of satellite estimates.

Rich Davis
Reply to  Kip Hansen
May 3, 2022 9:38 am

Kip ==> That sounds “Manntastic”

Something like Mike’s Nature Trick(tm)

Dave Fair
Reply to  Kip Hansen
May 3, 2022 1:27 pm

So, Kip, are you saying the SLR field (at least in Colorado) is as corrupted as paleo climatology?

Clyde Spencer
Reply to  Kip Hansen
May 4, 2022 7:25 pm


May 3, 2022 6:37 am

To measure the ocean’s rise (or fall) to a couple millimeters over a year is a fool’s errand. For example, if a high pressure system gets locked in for a month or so, the broad fetch of water it drives on it’s periphery will easily push enough water into an area to distort the average water level. About the best you can do is look at levels over a running period of years and even then you will have uncertainty.

But someone has to fund the grants, so you have to be a chicken little to drive the money train your way, and it is all about the money.

Rich Davis
Reply to  Kip Hansen
May 3, 2022 9:43 am

Another way to look at this…
Kip is far too generous in his characterization of pseudoscientists, to wit:

Both of these accomplished scientists have been publishing paper after paper…

Dave Fair
Reply to  Kip Hansen
May 3, 2022 1:30 pm

Again, corruption by politics, money and fame. Oops … I forgot ego.

Last edited 22 days ago by Dave Fair
Clyde Spencer
Reply to  rbabcock
May 4, 2022 7:31 pm

It is not unlike asking what the diameter is of something squishy and fuzzy (like a tennis ball) to the nearest micron. Rather that try to provide an answer that can’t be right, it is better to just suggest that the probable diameter is between an upper and lower bound. This is the time to use the fat lines that Excel provides as an option.

Ron Long
May 3, 2022 6:41 am

Good report about sea level going up due to termination of Little Ice Age. Remember the geologic record shows 40 meters higher and 150 meters lower sea levels (compared to current sea level) as normal variance. One minor issue is the comment about Global Isostatic Adjustment, when a substantial glacial load depresses land elevation, the land rebounds (gets higher) when the load is removed (when the glacier melts).

Gordon A. Dressler
May 3, 2022 7:05 am

Mr. Kip Hansen,

Thank you for your most excellent rebuttal (actually a complete takedown) of the work and publications of Boon and Nerem, both together and individually.

As for their attempts to make their models fit the actual measurements (i.e., data) of SLR:
it’s GIGO all the way down.

Reply to  Kip Hansen
May 3, 2022 8:05 am

No, like a bad tailor. A good tailor gets it right quite quickly, a bad one finally gives up and you are left with a poor fit.
I just hope that the AGW scammers get fed up soon.

Old Man Winter
Reply to  Kip Hansen
May 3, 2022 9:27 am

Sailors must always look dapper for those few hours of shore leave! 😉 My first
trip to Honolulu was the last day of the month- payday- & the fleet
was in town. Shore patrol cars were caught in stop & go traffic &
kept their blue & white lights flashing.

Even the thought of being able to tell the difference between open sea air &
that when one nears land wasn’t enough to entice me to be a sailor! 😮

Last edited 22 days ago by Old Man Winter
Dave Fair
Reply to  Oldseadog
May 3, 2022 1:33 pm

The scammers will not quit until OPM runs out.

May 3, 2022 7:08 am

Houston 2021 examined a large set of tide gauges with at least 75 years of data, and found a very, very tiny average acceleration of 0.0128 ± 0.0064 mm/yr².

However he also summarized the results of a total of ten studies, including his own, and the acceleration he found was the LARGEST of the ten.

An acceleration of 0.0128 mm/yr², continued for 100 years, would raise sea-level a grand total of 64 mm = 2.5 inches.

That’s obviously of no practical significance.

Here’s the paper:

Here’s the summary of ten studies, from his paper:
comment image

Last edited 22 days ago by Dave Burton
Rich Davis
Reply to  Kip Hansen
May 3, 2022 9:52 am

It’s only “nothing found” when the data contradicts the Party’s beloved hypothesis. You can be sure that if the data were to show a deceleration, even statistically significant, there would be no mention of it. And the focus would be on new adjustments to “fix” the data.

Don’t want to go afoul of the DGB/KGB and all that (Ministry of Truth).

Dave Fair
Reply to  Kip Hansen
May 3, 2022 1:42 pm

I’m sure you are aware that CliSciFi is not real science, Kip. And its getting worse (more dogmatic and strident) as more and more actual data come in on the various climate metrics that increasingly falsify cherished theories (ideology), especially as related to the UN IPCC CliSciFi climate models. Predicted economic realities are also screwing with implementation of their socialist plans.

Steve Case
Reply to  Dave Burton
May 3, 2022 10:03 am

My list of 65 long running tide gauges showed agreement with your meta study above. Here’s a distribution

20  less than 0.005 mm/yr
21  0.005 to  0.014 mm/yr
16  0.015 to  0.024 mm/yr
  8  0.025 mm/yr and over

Dave Fair
Reply to  Kip Hansen
May 3, 2022 1:45 pm

But the UN IPCC reports are chock full of dire acceleration predictions. Peer review at its finest.

Clyde Spencer
Reply to  Dave Burton
May 4, 2022 7:40 pm

There are more digits shown than are justified. That makes it look very precise to a casual reader.

It should be shown as: average acceleration of 0.013 ± 0.006 mm/yr².
Shown that way it is evident that the confidence interval is almost ±50%

May 3, 2022 7:08 am

Models and extrapolation

Think of a number…

Reply to  fretslider
May 4, 2022 3:34 pm


It’s –
“what number have we been told to produce?”

(and, “don’t on any account do ANY thinking!”)

Richard Hill
May 3, 2022 7:13 am

Satellites measure a large portion of the ocean surface, where most of the rise is frankly irrelevant. What does it matter what is happening in mid-ocean, literally nothing cares except those in the ‘nudge’ departments of our governments that seek to panic us. The tide gauges were installed for a good reason and tell an inconvenient truth.

Haven’t we had enough of junk science with covid modelling? Sadly though some will still believe the climate model scare stories.

Steve Case
Reply to  Kip Hansen
May 3, 2022 10:58 am

 if that sea level change does not arrive at the sea shore, not even of the islands, then it is a “who cares?”

And in other news, the alarmists have for years not even once told policy makers how much methane is on track to warm up the planet.

Clyde Spencer
Reply to  Kip Hansen
May 4, 2022 7:45 pm

Then there is the classic problem of subtracting two very large numbers with a small difference. What is the precision for sea level in the Bay of Fundy versus some small Pacific island with a tide range of 1 foot?

H. D. Hoese
May 3, 2022 7:19 am

As to VIMS, a lot downhill since they changed their name from the Virginia Fisheries Laboratory six decades ago. Still some good work, but their website “Living Shoreline” shows what looks like a failed marsh planting (they are not rare) and “A Graduate Student Walks into a Bar…” Probably coincidence? They have been sponsoring the Google Earth fish skeletons under Ocean, except for productive upwelling desert areas, most show lots of adjacent terrestrial vegetation. My major mentor was from a Virginia family in the oyster business, he would not be happy. Six decades ago they also had a new oyster disease epidemic, still don’t know the parasite’s life cycle. Spent lots of useless money and effort on an imported Asian species, funded lots of research on some already known.

As to the paper–“These numbers (satellite) agree well with projections from climate models.”

Barry James
May 3, 2022 7:20 am

Their first and biggest mistake was basing their “study” on the Jason radar altimetry data. Even NOAA disowns it as fit for experimental purposes only. From that point onwards it is just a mish mash of fiddling for the result they wanted. The fact that these charlatans get paid to produce rubbish like this is offensive.

Rud Istvan
May 3, 2022 7:32 am

Very nice post, Kip.

Nerem has made a career out of sea level rise acceleration, so in his mind it must be so—even if there is no observational data support. And that is precisely the ‘climate science’ problem.

Curious George(@moudryj)
Reply to  Rud Istvan
May 3, 2022 7:43 am

I always wonder why these types stop at using a second degree polynomial. Why not a third degree, or a fourth degree? You could get some REALLY scary results ..

Dave Fair
Reply to  Rud Istvan
May 3, 2022 2:09 pm

Rud (and Kip), we used to call these types cranks. Now that they are politically useful we call them esteemed senior scientists holding prestigious and lucrative positions and shower awards and cash prizes upon them. Michael E. Mann comes to mind.

Rud Istvan
Reply to  Dave Fair
May 3, 2022 2:36 pm

DF, an astute observation. Wadhams on missing Summer Arctic sea ice, Sterling on shrinking polar bear populations, and Mann on treemometers easily join your crank list.

Dave Fair
Reply to  Rud Istvan
May 3, 2022 3:29 pm

Rud, sadly the ranks of cranks has been swollen by frauds.

Reply to  Rud Istvan
May 3, 2022 3:29 pm

How many dimensions does reality really have? String theory says more than observable and some views of quantum mechanics suggest hundreds.

Steve Case
May 3, 2022 7:40 am

I get about 1.9 mm/yr 2020-2100 from figure 1

NOAA says: “The graphs give an indication of the differing rates of vertical land motion, given that the absolute global sea level rise is believed to be 1.7 +/- 0.3 millimeters/year during the 20th century.”

And they hide it in the middle of a page in the middle of a paragraph and say so only once. Here’s that page

Nerem is convinced that sea level rise must be accelerating. He has written papers and presentations and mostly convinced the IPCC and policy makers that that acceleration (by which he means sea level is rising faster and faster) it actually taking place in the real world in which we live and breathe.

Here’s his presentation crying the blues that there isn’t any acceleration.

Here he’s hoping really hard to detect sea level rise acceleration

Here he’s claiming acceleration has been detected. An illustration of Snoopy’s happy dance would be appropriate.

The satellite record of sea level change is now of sufficient length that we can begin to detect climate-driven signals in global mean sea level (GMSL) change (e.g., Nerem et al., 2018).

That’s bullshit, if you try to find acceleration from the tide gauges over that short span, they are all over the map

Even at their most enthusiastic, Nerem et al. have sea level rise acceleration at 0.1 mm/yr2. 

His web page says 0.098 mm/yr²
Really? he couldn’t round it off to 0.1 mm/yr²

Thank you for this post, sea level and methane don’t get enough ink. Those are the two issues that can really do some damage if the crazies running the asylum continue to get their way. 

Dave Fair
Reply to  Kip Hansen
May 3, 2022 2:13 pm

Kip, in CliSciFi it is typified by Dr. Judith Curry’s drunk only looking for his keys at night under a lamppost.

Steve Case
May 3, 2022 7:42 am

So I’m queued up waiting for approval.

Steve Case
Reply to  Steve Case
May 3, 2022 7:52 am

I forgot this title from C-SLRG:

“Satellites Detect Pothole on Road to Higher Seas”

They couldn’t be more transparent if they tried.

May 3, 2022 7:44 am

“Since our quadratic model performs well for the period 1960–1993, it can reasonably be expected to perform similarly for the next 30 years.”
Statistics and Sampling Theory say otherwise.

May 3, 2022 8:02 am

A shopkeeper at the end of the day looks in the till and counts the money made that day. Meanwhile a professor steps in and says, “um, actually I’ve calculated your daily take based on the kinds of shoes worn by people in the Starbucks next door…”

That is how this reads to me. Perfectly good, sensible and accurate data is being set aside for speculation and guesswork.

Tortured methods from tortured minds.

Thanks Kip for presenting and correcting what is masquerading as science these days.

Dave Fair
Reply to  Kip Hansen
May 3, 2022 2:24 pm

Kip, the same thing might be motivating some of the paleo climatological community in disappearing the Holocene temperature variations, including the Medieval Warm Period and Little Ice age. Michael E. Mann (head of the Hockey Team) and some of his followers, however, are nothing but charlatans, with Mann additionally being a thug.

Old Man Winter
May 3, 2022 8:57 am

Here’s a quote from a previous WUWT post saying NASA inflated the SLR by 0.3mm/yr due to the
seabed sinking (GIA). Do they still do that?

“What’s more, the second graph is not really just from tide gauge data; it’s from tide gauge data inflated by a +0.3 mm/yr GIA “adjustment,” to subtract off the rate by which the sinking ocean floor is hypothesized to reduce sea-level rise. The real rate of coastal sea-level rise from averaged tide gauge measurements is only about 1.4-1.5 mm/yr (under six inches per century), and that rate hasn’t increased since the late 1920s.”

Since MSL is a measurement of the sea level above the center of the earth, this sounds dubious at
best as the seabed level is immaterial & can be accounted for.

Last edited 22 days ago by Old Man Winter
Kevin kilty
May 3, 2022 9:06 am

There are people who become so invested in their pet subject/theory that they cannot consider they may be wrong. This is a characteristic of what Irving Langmuir called pathological science. A good analogous situation to sea level acceleration is the “Palmdale Bulge”. R.O. Castle discovered the bulge around 1972 or so, and over the next decade had convinced quite a few, maybe a majority of, geophysicists of the reality of this curious feature — lots of grants for research and field work. In 1980 at an AGU meeting someone explained the origin of the bulge in erroneous data reduction of first-order leveling. By 1982 the last believer in the bulge was … R.O. Castle.

Reply to  Kevin kilty
May 3, 2022 12:00 pm

Thanks for the information. Nice lunchtime research diversion.

Clyde Spencer
Reply to  Kevin kilty
May 4, 2022 7:57 pm

What T. C. Chamberlain called “the dangers of parental affection for their favorite theory. If you haven’t read his Method of Multiple Working Hypotheses, I highly recommend it.

May 3, 2022 9:44 am

Lesson one in Squires Practical Physics: do not use a higher polynomial fit if a linear fit is sufficient.

Steve Richards
Reply to  Kip Hansen
May 4, 2022 10:16 am

I just read the preview pages on that link.
What a good book.
A must for climate scientists with its discussion on error etc.

The Dark Lord
May 3, 2022 10:01 am

Even at their most enthusiastic, Nerem et al. have sea level rise acceleration at 0.1 mm/yr2. “

anyone that thinks we can measure sea level GLOBALLY to an accuracy of 1 mm using moving instruments hundreds of miles away from oceans with WAVES in them is smoking some good stuff …


^ that is greater than the annual “rise” we are supposedly measuring …

just because you can “measure” something doesn’t mean you have valid data to work with …

May 3, 2022 10:01 am

TIL Jakarta is sinking so fast, that it will soon be abandoned, and Indonesia is building a new capital called Nusantara that will be on the island of Borneo. Some parts are sinking up to 25 cm per *year*. Of course, the article I read had the obligatory blurb about sea level rise, but one meter over a many decades is nothing when your city will literally be sinking into the ocean in a few years, due to ground water pumping, density of infrastructure, etc.

May 3, 2022 10:09 am

NOAA is backing the work associated with a comprehensive plan to manage Oregon beaches (better).

Sea level rise & the decrease in recreational opportunity (as the beaches narrow), and sneaker wave danger, all play into the stated need for ‘better’ management of the beaches. (did you know that sneaker waves are one of, if not the biggest, natural hazards in Oregon?)

One of the questions on the recent survey (NOAA/Oregon State University (Econ & Ag depts)) was: How likely would you be to vote for a Statewide measure that increases income tax $150/yr (average) to pay for a coastal comprehensive plan, if it included changing the current rules that restrict property owners from paying for and protecting their own property.

It appears that they (Oregon) are fishing for about a $100,000,000 annual budget to fart around with. (and are paying OSU a big pile of money to research the appropriate propaganda to peddle the request).

Anyway, does anyone have any honest data on SLR for the Oregon coast?

Last edited 22 days ago by DonM
Reply to  Kip Hansen
May 3, 2022 10:32 pm

When the plate of Juan De Fuca finally slips and releases it’s 700 year subductively stored energy along the Oregon coast, no one is going to be concerned with 1.7 mm/yr sea level rise.

The proof is seen at the Neskowin Ghost Forest along the Tillamook coast.

Joe Born(@jhborn)
May 3, 2022 10:32 am

Fig. 4 here illustrates how Raymond Pierrehumbert attacked Steven Koonin’s statement that the rate of sea level rise now is no greater than it was early in the 20th century.

Dave Fair
Reply to  Joe Born
May 3, 2022 3:24 pm

More evidence of CliSciFi corruption. The whole field of climate science needs a thorough audit.

Kevin kilty
Reply to  Joe Born
May 4, 2022 7:14 am

Excellent essay, Joe. I had never heard of Nap town by the way — cool.

Smart Rock
May 3, 2022 11:00 am

Thanks to Kip for exposing this piece of mathematical sleight-of-hand, which is unfortunately typical of climate “science”

The idea that a simple quadratic equation could possibly represent such a complex natural phenomenon is intellectually bankrupt. Sure, you can fit selected segments of a time series to a quadratic, but once you try and extend it beyond those selected segments, it goes into crazy territory, as in Kip’s figure 4, and as they say themselves “We chose not to extrapolate beyond 2050 in this work because the errors become large quickly

Their “process-based argument” for using a quadratic is a transparently overt exercise in the same circular logic that underlies all the GCMs, and it starts with the assertion (which of course may not be questioned) that GHGs are solely responsible for recent warming.

The whole point of the paper is to generate scary numbers for future SLR. In other words, it’s mainstream Climate Science.

The triumph of reason and logic that we call the 18th Century Enlightenment has run its course. We’re back in the domain of dogma and beliefs that may not be challenged. Oh well, it was fun while it lasted.

May 3, 2022 3:41 pm

Could someone share the actual quadratic formula they use for their model? Also, they state that their projections closely track IPCC and others, but 2100 is a more commonly used end date for the X axis in such projections so can someone calculate what their projected high/low confidence interval limits would be at 2100?

May 3, 2022 4:40 pm

Kip, Nice article — several things.

  1. Have you seen this old post by Gavin Schmidt? ? The takeaway? “If your data doesn’t look like a quadratic, don’t fit a quadratic to it.” He follows up with a rather contrived example that does, in fact, yield atrocious results. Good point I think. No, the data doesn’t look quadratic to me.
  2. There was a time several decades ago when I actually knew a little about extrapolating data, There was some literature on the subject back then. Probably there’s more now. As I recall it’s not easy to do. Lots of pitfalls. In particular, for anything but a linear fit, data near the ends of the curve tends to have an undue effect on the results.
  3. If it were up to me, I would fit to an exponential (constant rate of increase) not a quadratic. It’s easy to do. Just do a linear least squares fit to the logarithms of the observed values. And I actually had some decent results doing that with some computer related stuff back in the 1990s.
  4. (Somewhat off topic) In one of your earlier sea level articles, you asked why it was important to run RA satellites in parallel for a while when a new instrument is launched into orbit. I had to think about that for a while. I think the issue is that the hardware in orbit may have slightly different signal handling characteristics even for more or less “identical” instruments. Even a few cm of difference in cable lengths or a small difference in signal processing will probably alias into a different “altitude”. They’ll correct most of that while calibrating the instrument on the ground. But a bit of bias will likely remain. As long as the bias is just an offset, it doesn’t matter for data from the same instrument at different times. When they subtract the two numbers to get sea level change, any fixed offsets go away. But when you want to compare results from different instruments, you need to know the offset between them. So, you run the satellites in parallel until you know the offset in reported altitudes. There’s some other stuff along the same line, but this comment is already too long.

Anyway, nice article.

May 3, 2022 4:45 pm

Well done Kip.

May 3, 2022 6:24 pm

When you have data that shows periods of greater and lesser acceleration, stable rise, and even periods of deceleration, you have to ask whether the detection of a recent acceleration/deceleration is a long-term thing or just happens to be the result of a short-term event (or several short term events strung together). An example of a short-term event happened in 2011 when the rainfall in Northern Australia and a few other places was so unusually high that much water was impounded and the global sea level actually fell.

You can never determine the long-term future trajectory by looking at only a short period of recent data; the more variable the data, the longer the period needed to make any long-term projection. It’s totally bogus to use the last 27 years of data, especially with all of the ups and downs, to project that the (tiny) acceleration seen will last 27 years into the future.

Reply to  Kip Hansen
May 4, 2022 12:07 pm

Nope, short term acceleration/deceleration is a thing.

See: The 2011 La Niña: So strong, the oceans fell in the Geophysical Research Letters by Boening et. al.
Here’s the abstract (emphasis mine):

Global mean sea level (GMSL) dropped by 5 mm between the beginning of 2010 and mid 2011. This drop occurred despite the background rate of rise, 3 mm per year, which dominates most of the 18-year record observed by satellite altimeters. Using a combination of satellite and in situ data, we show that the decline in ocean mass, which explains the sea level drop, coincides with an equivalent increase in terrestrial water storage, primarily over Australia, northern South America, and Southeast Asia. This temporary shift of water from the ocean to land is closely related to the transition from El Niño conditions in 2009/10 to a strong 2010/11 La Niña, which affected precipitation patterns world-wide.

Reply to  Kip Hansen
May 5, 2022 3:00 pm

If you want to see if the tractor-trailer is making better time in his last mile than he has averaged over the first part of his trip, you have to measure his speed over the trip and over that last mile. If he is going faster than his average, you don’t know if he has steadily accelerated slowly over the whole trip, if he has just accelerated quickly over the last mile, or if his speed has been going up and down the whole time unless you measure his speed frequently throughout the whole trip.

It’s the same with the sea-level. We can’t predict that a recent acceleration will persist over a long time PRECISELY because we have seen short-term acceleration and deceleration events before (and events that were even greater than any recent acceleration), and we don’t know why. You are arguing that acceleration is something other than what it is.

There are statistical tests to see how reliable a prediction should be based on the fluctuations seen over the whole data set. I spent much of my career calculating several of these different statistical tests for radiation transport.

While I agree with you that the total error in measuring sea-height is about 2cm, the relative change seen over a given satellite must be much better than that, otherwise we would be seeing random events like we saw in 2011 quite frequently. You can even predict how frequently. But 2011 was indeed an unusual event – if you don’t believe it, review the photos of the huge areas of water impoundment in Northern Australia.

Reply to  Kip Hansen
May 6, 2022 11:45 am

Tidal gauges are influenced by wind patterns over large areas that can (and do) change.

Some tidal gauges DID show the 2011 event. For example, the gauge at Victoria B.C. Victoria just happens to be near where I live on the Puget Sound and was the first gauge I grabbed.

comment image

You do not expect that all tidal gauges will move in lock-step.

The 2011 event showed up on the land surface as huge temporary lakes on THREE continents. This wasn’t an error in satellite altimeters, it was quite evident to anyone who put a boat in one of the lakes. It was also evident to other types of satellites too.

See “Satellite Picture of Australian Floods That Now Covers an Area as big as Texas”

Changes in rainfall patterns around the world happen and they do influence the rate of rise (and fall) of the oceans. More rain falling over the ocean surface means less water impounded over land and the ocean rise temporarily accelerates. More rainfall happening over land means more water impounded and the rate of ocean rise temporarily decelerates. The fact that these events DO happen (but they’re not all as impactful as in 2011) puts the lie to alarmists who claim that an acceleration can be detected simply by observation of the recent sea-level rise.

May 3, 2022 9:02 pm

The situation could be likened to civil engineers of 1900 being forced to plan their streets and highways to accommodate” 300 million horses, and the accompanying waste stream.

Kevin kilty
May 4, 2022 7:27 am


If I put on my “likelihood” hat, and presuming all data going into that global trend have been vetted carefully to remove obvious blunders, I can see strong support* for a linear increase in MSL over the past century plus. But who needs to? The linear trend is obvious. On the other hand, If I try to see a quadratic trend I find it has just about no support at all — there is too much noise in the data at a variety of time scales. I could make this a quantitative statement with a likelihood ratio, but it’s becoming spring up here above 7,000 feet and I have a bad case of senioritis.

*-support is a real concept. See A.W.F. Edwards or R. Royall.

Last edited 21 days ago by Kevin kilty
Clyde Spencer
May 4, 2022 7:21 pm

… it can reasonably be expected to perform similarly for the next 30 years.

In what multiverse? Nobody can predict the future with certainty, despite charlatans and prophets attempting to do so since the beginning of our species. If anyone could actually do so, they would be richer than Bezos or Musk.

When a deterministic system is understood very well, past history can provide an insight on what future trends may be. However, there is no ability to incorporate unknowns such as the asteroid that killed off the dinosaurs, or the three major volcanic eruptions that Hansen speculated would occur, but didn’t.

Tim Gorman
Reply to  Clyde Spencer
May 5, 2022 5:15 am

It doesn’t have to be a major occurrence to falsify a prediction. It could be something small. Think trying to predict when the next train derailment will happen on a rail line. No one has enough understanding of all the possible causes (erosion, metal fatigue, car suspension failure, etc) to even forecast where it will happen let alone when it will happen. Each of these causes are small and build over time. It’s the same thing for predicting warming or cooling. No one knows enough to get a prediction correct. We do know the next ice age will happen, just like we know the next train derailment will happen. But that doesn’t help much in forming predictions that are actually useful.

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