Sea Level Rise ‘Alarmist Agitprop’

Guest post by Rud Istvan

Fabius Maximus alerted Charles the Moderator to a new alarming ‘agitprop’ paper in Nature Communications (here) concerning global warming induced sea level rise (SLR). Since I previously contributed to WUWT on SLR and its lack of acceleration, CtM asked if I would provide a guest post reviewing this new SLR paper. I read it and explain below why you don’t have to. The post title is h/t to Fabius Maximus’ alerting email to CtM.

The alarming new paper by Kulp and Strauss is titled (paraphrased) “New DATA triple estimates of SLR vulnerability”. One knows immediately that agitprop follows, since the paper is about a new way to model coastal land elevations. Models produce data only in alarmist climate circles.

The paper has two parts. The first is a new way to remove a known high bias in coastal elevations derived by SRTM (satellite altimetry like that used to estimate SLR). The land problem is that satellite altimetry ‘sees’ the land’s top surface, not the actual land underneath a forest canopy or a cityscape. The alternative much more accurate and expensive method, airplane flown LIDAR transects, has only mapped the US and Australian coastal regions of those two wealthy countries. Comparison shows an SRTM positive US median bias of +3.7 meters!

The new method used for SRTM bias correction is a software neural network (a form of artificial intelligence, AI) incorporating 23 variables. The AI was trained on the US LIDAR/SRTM discrepancy, and then validated using Australia. That is a robust AI software methodology. Good work.

Unfortunately, the AI bias correction was good but not great. For those two countries, AI cut the root mean square error (RMSE) of SRTM compared to LIDAR ‘roughly in half’ (translation, to ‘only’ ~1.8 meters). The discussion in the paper uses South Florida as a physical example of the remaining causal bias. The neural network failed because South Florida’s coasts are densely populated with many high-rise condos (in between is a virtually uninhabitable Everglades), compared to the entire US coastline it was trained on. As an example of new AI induced error, the AI model applied to ‘current’ global coastal populations estimated that 110 million people already live below mean highest high water (MHHW). Which is sort of true for Miami’s South Beach during King tides, but way more people than just Dutchmen on their polders. I give kudos to the authors for being honest and illustrative about the remaining and newly introduced SRTM uncertainties after their AI ‘improvement’.

My only criticism of this first part is that the paper explicitly did NOT make the AI code available to scrutinize for logic and coding mistakes.

With this new AI model of SRTM bias ‘sort of firmly except not’ in hand, the bulk of the paper then uses it to TRIPLE SLR climate alarm.

To do that, the paper starts with a survey of some (ten to be exact, footnotes 3-12) of the many already alarming SLR papers that exist. The paper uses some of the usual suspects WUWT has previously discussed, including several WAIS instability speculations. That survey concludes +20-30cm of SLR by 2050 (so SLR had better hurry up and start accelerating), and +70-100cm by 2100 for RCP4.5. By comparison, most serious observational SLR papers predict less than 20-30cm by 2100 under business as usual, not a meter under RCP4.5. No SLR acceleration is evident in long record differential GPS corrected (for vertical land motion) tide gauges. So ~2.2mm/year with closure equals about 22 cm for the 21st century. The climate alarm survey bias is evident from that fact alone.

It then proceeds to model how many people end up under water. The first scenario illustrated in the body of the paper (most are in the SI) is ‘median K17/RCP8.5/2100’. It is the basis for the climate disasters illustrated by paper Figure 1 for the Pearl River Delta, Bangladesh, Jakarta, and Bangkok. (I checked the paper MSM PR. Figure 1’s Bangladesh and Bangkok are very popular.)

This scenario identifier needs explicit decoding, which no one I could find in the MSM PR about this paper, or using parts of Figure 1, has yet done.

1.Checking footnotes, we find that this new paper’s SLR scenario K17 expressly ‘includes early onset WAIS instability’. The old and thoroughly discredited ‘WAIS slides into the sea’ about Pine Island Glacier and the Amundsen Embayment.

2. RCP8.5 is the physically impossible but real bad one from AR5.

3. 2100 is sea level that year, based on CMIP5 climate models that provably run hot in the tropical troposphere by a factor of over 3x.

Applying that doubly impossible and 3x hot erroneously climate modeled scenario to the ‘current’ populations of global coastal areas, the new AI model ‘data’ shows that over 400 million people will be flooded out. The paper then carefully notes that the actual climate impact will be much worse because of population growth—so the new estimate is conservative.

Still high bias understating disaster! Conservative estimate! Triply alarming!


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November 3, 2019 2:45 am

Can anybody help greta, she needs a lift back to spain, she used her fossil fuel made mobile phone to ask on twitter 😐 “A wooden boat with wooden ores will be best, as plently of slaves will be available to follow my every word” (sarc)

Ed Zuiderwijk
Reply to  Sunny
November 3, 2019 4:27 am

I know a place in Cozumel where she can rent a pedalo for four. Find three muscular Vikings to cycle you across to Spain. When you approach the Galician coast take care to switch to surfboards as the waves there are a really serious proposition.

Reply to  Ed Zuiderwijk
November 3, 2019 7:01 am

I suggest she surf in at Portugal

Mike McMillan
Reply to  TRM
November 3, 2019 12:01 pm

CAGW true believers think she could walk across.

Reply to  Ed Zuiderwijk
November 4, 2019 6:43 am

The only all natural material surf board (I freely admit ignorance of surfing) I’ve seen is one made of kona wood in Hawaii. Can she use that?

steve case
Reply to  Sunny
November 3, 2019 4:45 am

“A wooden boat with wooden ores will be best …”

Since she is a VIP and those ships have three slaves per oar she should be given a choice of port or starboard, fore or aft and position one, two or three.

Reply to  steve case
November 3, 2019 8:08 am

Green Slavery, but only when the sun doesn’t shine, or the wind exceeds a tolerable range.

Jeff Alberts
Reply to  Sunny
November 3, 2019 8:14 am

Why do people insist on posting OT??

Reply to  Jeff Alberts
November 3, 2019 9:47 am


Agreed, Rud would have done a lot of work on this and it would be polite to acknowledge that subject. I think a weekly ‘unthreaded’ would be a worthwhile new section whereby all sorts of things could be discussed.

In the meantime, thanks Rud for reading this paper so we don’t have to


Reply to  tonyb
November 4, 2019 12:40 am

This post is not about Greta!

Johann Wundersamer
Reply to  Jeff Alberts
November 16, 2019 12:52 pm

OT. NG, Jeff.

Reply to  Sunny
November 3, 2019 8:49 am

Can’t she just walk? Being the lefts new Savior and all.

Joel O’Bryan
November 3, 2019 2:50 am

That survey concludes +20-30cm of SLR by 2050…
So….low range….
200mm/30 years = 6.7 mm/yr, which is 3x today’s 2.2 mm/yr.

Are those author’s smoking a crack pipe? Or just a grant butt-snorkle?

Jaap Titulaer
Reply to  Joel O’Bryan
November 3, 2019 9:51 am

Well, even 67 cm in 100 years does not impress us (NL). Quite some time ago the 10000-year flood scenario had been updated to include a mere extra 60 cm, it’s included in current upgrades (mostly done during maintenance, when needed)

Quite normal waves in the North-Sea are as high as 4 m. Springtide brings a wall of water 12 m (36 feet) high. So were not impressed by a mere 0.67m extra.

Of course, it’s all nonsense multiplied by 3.

Michael Howlett
Reply to  Jaap Titulaer
November 3, 2019 12:52 pm

Yup 😱

Alastair Brickell
November 3, 2019 2:51 am

Here’s a link to a totally uncritical interview with the paper’s co author Ben Strauss on Radio New Zealand (RNZ) from this Saturday:

Reply to  Alastair Brickell
November 3, 2019 7:07 am

Even if it rises as fast as that audio suggests my dear old grey haired mum with her polyurethane knees and ceramic hips could outrun it. Seems to be a lot of made up fuss about nothing threatening anybody.

Rod Evans
Reply to  Alastair Brickell
November 3, 2019 7:42 am

Thanks for the link Alastair.
Anyone listening to that very calm interview would come away imagining it is evidence of yet more disaster ahead of us. I wonder if NZR will allow anyone to put the critic we have just read on air? Somehow I doubt it. The host of the show seemed so delighted to announce, Thank you professor for that very depressing news. It was just what she wanted to hear. She had no idea or interest in actual science or balance. The other take away was the constant reference to the Paris accord. The now blind adoption of “we must follow the Paris agreement, if we don’t the situation will be much worse than even this projection”.
The constant push by the media to big up any and every climate research that projects doom and disaster is part of the depression in peoples minds leading ultimately to suicidal tenancies.
Hey ho, another day another meaningless doom broadcast.

Tom Abbott
Reply to  Rod Evans
November 4, 2019 8:25 am

“The other take away was the constant reference to the Paris accord. The now blind adoption of “we must follow the Paris agreement, if we don’t the situation will be much worse than even this projection”.”

Which reminds me: Today is the day President Trump is supposed to submit the formal withdrawal of the United States from the Paris Climate Accord

Martin Cropp
Reply to  Alastair Brickell
November 3, 2019 1:22 pm

RNZ is a hot bed of alarmist propaganda. I have sent very pleasant emails to them offering charts and simple explanation contrary to their constant alarmist diatribe. No answer at all. They are after all the communications arm of the government.

November 3, 2019 2:59 am

In a fantasy world, it would amusing to see Govts offer the large majority of funding to research the potential benefits of a warmer increased CO2 world. Amusing…to watch how many scientists jump ship for funding.

November 3, 2019 3:15 am

In early 2018, over on the AGU website several authors project even farther out to 2300.
In their assessment:
Even with climate change mitigation, the land area exposed to coastal flooding will continue to increase for centuries. Adapting the coast to cope with rising sea levels is inevitably required.
DUH. (but we’ve only got 280 years to implement this “adapting” OMG!

Don K
November 3, 2019 5:58 am

In fairness, even though there’s no particular reason other than dubious modeling to expect SLR (roughly an inch a decade for the past century or so) to accelerate, there’s also no particular reason to think SLR will stop any time soon. In any case, potential storm surge is a significantly more serious issue than SLR. If developers and those in charge of building permits took storm surge into account properly, most ocean front “development” would be substantially further back from the sea.

Step back from the water, and no one gets hurt.

Kurt in Switzerland
Reply to  Don K
November 3, 2019 7:42 am


You do what the Dutch did (and continue to do): they recognized that storm surges are real and that much of their land was below sea level. Instead of relocating (abandoning) their towns and farms, they built storm surge barriers, systems of dikes & levees for flood prevention & control.

Massive investment in the 1950s.

And the country still exists today.

Somebody should advise Climate Central, the Dems, the E.U. & the U.N. that this works better than “putting a tax on Carbon”, Cap ‘n Trade, a “Green New Deal”, “Climate Guilt” shakedowns / indulgences, a “Green Climate Fund”, “Carbon Neutrality”, “Zero Net Carbon Emissions by 2050” or other such childish nonsense.

Don K
Reply to  Kurt in Switzerland
November 3, 2019 9:25 am

Kurt: The Dutch (and British) only sorted out their sea defenses after a North Sea storm in 1953 breached the dikes in numerous places, killed 1800 people in the Netherlands alone and flooded a significant portion of the country. Most of the rest of the planet has not hardened their coastline against the strongest likely storm, and frankly a lot of it isn’t worth the cost of protecting and some of the remainder isn’t protectable in any rational fashion. That doesn’t preclude using the land for farming, recreation, mineral extraction, etc. It just means that people mostly shouldn’t live there unless their communities are hardened against storm surges and tides adding in many cases to maybe 6 to 10 meters. And if dikes are impractical or too costly, there needs to be a realistic possibility of evacuating people and livestock from un/poorly protected areas.

BTW — The US tried the “just build dikes” approach in New Orleans. In 2005, a tropical cyclone that came ashore well to the East of New Orleans breached the dikes in numerous places, flooded 80% of the city, killed 1400 people, and caused $70B worth of damage. It’s not that dikes can’t work. The trouble is that in places other than the Netherlands, you’re likely to end up with Potemkin storm defenses that won’t work when put to the test.

Michael Jankowski
Reply to  Don K
November 3, 2019 2:08 pm

Don K,

To be fair, New Orleans’ flood protection is nothing of the scale of the Dutch…but held during Katrina.

The levees that failed in the days following Katrina were due to flawed design.

Jaap Titulaer
Reply to  Don K
November 3, 2019 2:56 pm

The issue is that putting the correct protection, including dykes, in place to protect New Orleans against Hurricane surge floods will cost MUCH less than the damage of that single event, BUT it will still be billions of dollars. Hence people seem to be hesitant to do what is needed.

It is a question of serious planning and making serious cost calculations versus any other approach of belief.

BTW: AFAIK the Dutch are now advising New Orleans.

Reply to  Don K
November 3, 2019 8:39 am

People LIKE to live by the water, and highly value open views of the water.

So what people do in highly regulated advanced civilizations like Florida is the building codes required that first floor elevations be raised to be a little above the estimated flood elevation. Which is no big deal – just use piling foundations. The newer homes built since the revised storm related building codes are all up high. Views are better there anyway. And the open space underneath is used for parking and storage, and may either be open or enclosed with tear-away panels that get replaced after the flood at relatively little cost.

Problem solved. Easily peasily solved. No human catastrophe.

For those homeowners who have homes built prior to the current codes, they are forced to buy flood insurance .. or else they can either raise their existing homes up on pilings, or tear down and rebuild to code.

Regardless of what actual sea levels do in the future, this is common sense building technique in coastal areas. After all, storms on the sea coast are nothing new.

spangled drongo
Reply to  Don K
November 3, 2019 8:21 pm

“there’s also no particular reason to think SLR will stop any time soon”
Don K, the tide gauge in Sydney Harbour, Australia, while showing a trend of SLR of ~ 2 inches per century is actually today showing a 4 inch FALL in mean sea level since the first recording 105 years ago:

This is adjacent to the broadest stretch of ocean in the world. So there is nothing different happening with sea levels than what has always happened.

The world’s coral atolls are also increasing in size.

November 3, 2019 3:34 am

Anyone who puts their faith in AI right now needs their head examined.

Better still, strap them into an F1 car with no pedals, no steering wheel, and have AI control it for them during a race start. (Standing start in F1 so the results at the first corner can be carnage).

Then move onto a harder task, controlling a MOTOGP Motorcycle at a similar standing start with, more often than not, similar levels of carnage at the first corner.

Fortunately, thanks to human instinct, care for fellow drivers/riders and unbelievable levels of skill, there are rarely fatalities.

However, compared to climate change/sea levels etc. these skills will be relatively easy for AI to master.

Reply to  HotScot
November 3, 2019 3:36 am

Oh come on MOD, this is ridiculous. Two perfectly reasonable comments sent to moderation.

Are there no guidelines for regular posters to avoid this?

John F. Hultquist
Reply to  HotScot
November 3, 2019 9:05 am

Perhaps get rid of the “hot” – –
Try CoolScot.
If that doesn’t work, have a glass of wine and relax.

There is a well known phrase, but I’ll paraphrase:
Moderation happens.

Reply to  HotScot
November 3, 2019 7:26 pm

My comments used to be posted right away. Now I wait for, well, awhile.
I was wondering if I became socially unacceptable, or the rules changed.

Reply to  Rotor
November 5, 2019 11:56 am

Not sure, but I think I heard that moderation approval occurs at hourly intervals (not sure at what point). So your comments should get posted anywhere between hardly any time and 1 hr. And there’s keywords that can delay that.

Don K
Reply to  HotScot
November 3, 2019 6:55 am

Hotscot: I somewhat share your opinion of AI. The idea that some sociopath might use Artificial Intelligence in, for example, controlling the velocity and trajectory of autonomous vehicles is pretty terrifying. However, I’m not sure that using neural networks is any worse than passing off elaborate, poorly understood, unvalidated, statistical models as “science”. At least, unlike the climate modelers, these people seem to be actually trying to validate their results. The klimate kids OTOH, seem to prefer hyping their models to checking/fixing them.

Johann Wundersamer
Reply to  HotScot
November 16, 2019 1:13 pm
son of mulder
November 3, 2019 3:38 am

Is there a graph going back to the start of the 20th century that shows how much thermal expansion and how much melting land ice contribute to measured sea-level rise? Do the go forward models delineate between these two contributions? If so how do they compare?

Reply to  son of mulder
November 3, 2019 4:15 am

Let’s add to this the water drained from many of the largest aquifers, now returned to the oceans. This is not trivial.

Reply to  Mark
November 3, 2019 4:59 am

It’s amazing to me that we can pump enough water into the oceans to make a difference…

…and yet the solid sediments washing in from rivers and erosion doesn’t

while at the same time…claim so much sediment is being diverted to the ocean…the land is disappearing

Amazon >comment image

Mississippi >

Bangladesh >comment image

Reply to  Latitude
November 3, 2019 7:14 am


“…and yet the solid sediments washing in from rivers and erosion doesn’t.”

Sediments (erosion, fluvial deposit) are of great relevance for paleostudies, but do not account for much within e.g. 50 or 100 years.

Maybe you have time enough to read a bit of this:

Sea-level responses to erosion and deposition of sediment in the Indus River basin and the Arabian Sea

Out of the abstract:

Our analysis highlights the role that massive fluvial sediment fluxes play in driving sea-level changes over > 1000-yr timescales from the Indus River, and, by implication, from other rivers with large sediment fluxes.

Nota bene: what pdf creators do to hinder us in pasting even an article’s title is incredible. Luckily, there are some nice tools in UNIX’s toolbox.

Reply to  Bindidon
November 3, 2019 9:51 am

I don’t agree at all….

every river is dumping sediments…constantly… and almost consistently

much more than pumping water….or rain in Australia

and there’s millions of them >comment image

Reply to  Mark
November 3, 2019 11:25 pm

Not sure where you live, Mark, but the Australian Great Artesian Basin covers an area of 1.7 million square kilometres, and contains an estimated 64,900 million megalitres (ref:
I could not easily find data on discharge / recharge – maybe you can let us know if it is in danger of running dry when you have read thru the site.

November 3, 2019 3:39 am

The problem of false land level recording due to tree cover has been known for years, ever since airborne topographical surveys were started. This was particularly so in forest and jungle areas where, from the tops of tree levels the are looked relatively flat but was in fact covered in vast areas steep , low, and twisting hill ridges.

Having said that, can anyone briefly explain the accuracy of any sea level rise measurements from satellite readings, when the local time, winds, waves, and tides including seasonal high and low tide peaks massively affect the local sea levels when measured, compared to the claimed level changes.

Reply to  Peter Wilson
November 3, 2019 5:27 am

Let’s take an easy case.

Suppose that I have a radar pointed at a stationary target. The target is small and the signal is weak so any particular return pulse will have big error bars. We say that the signal has a poor signal to noise ratio.

As long as the errors are truly random, we can average many return signals and know the distance between the radar and the target as accurately as we want. The accuracy is dependent on the number of samples. If the errors aren’t truly random, all bets are off.

joe - the non climate scientist
Reply to  commieBob
November 3, 2019 6:15 am

that doesnt work if the measurement error is stytemic

Reply to  joe - the non climate scientist
November 3, 2019 8:24 am

Absolutely. All the errors must be known to be random. That’s actually a rather high bar.

Reply to  commieBob
November 3, 2019 2:54 pm

But the variations that I mention are a mixture of variable value cyclic events and variable value random events.

Reply to  commieBob
November 3, 2019 7:09 am

I understand the point you are making and agree with it, but the radar analogy is is poor analogy to use. If a weak return signal registers at the receiver all it will be as accurate as if the return signal was strong.

Now, it is possible that if the signal of the object the radar is pointed at is weaker than other objects in the radar beam, or the back ground noise, the radar will give an accurate measurement of another object in its field of view. This is the problem of police radar. The car they point their radar gun at is not necessarily the object it will measure.

Reply to  KT66
November 3, 2019 8:30 am

It was the best analogy I could think of. In real life, things get complicated.

Reply to  commieBob
November 3, 2019 1:24 pm

Perhaps I was being being a bit pedantic. Please accept my apology.

Rud Istvan
Reply to  Peter Wilson
November 3, 2019 12:12 pm

PW read my post on Jason 3. CtM made it the center link under the guest post, the one with the bullseye targets.

November 3, 2019 3:46 am

Thanks for the info.

I’m satisfied with the results presented here

Persistent acceleration in global sea-level rise since the 1960s
Dangendorf & al.
(unfortunately under paywall)

Data for interested persons, to compare with C&W, Jevrejeva & al. etc:

No AI needed by Sönke Dangendorf and colleagues, natural brains were enough.
But I guess this will also fall into the unavoidable ‘alarmism’ trap.

No problem for me!

J.-P. D.

Ed Zuiderwijk
Reply to  Bindidon
November 3, 2019 4:37 am

Why is rms error systematically going down from 25 to 3 mm? Were the early observers less skilled? Or do they have nowadays better instruments? I doubt the former, but if the latter why the systematic decrease and not a decrease in steps?

Reply to  Bindidon
November 3, 2019 7:23 am

Lots of problems for me though. When I read a paper that is supposed to be based on tidal gauges complemented with satellite records, I sort of expect it to be based on actual tidal gauge data.

This one isn’t. It is based on what they think the tidal gauges ought to have shown if they were there, when unfortunately they weren’t. An example, here is their version of tidal data for Port Hedland (figure S1) starting in 1900:

And here is the real tidal gauge data for Port Hedland, staring in 1966, but with several gaps:

comment image

And they haven’t even managed to get the interannual variability reasonably correct in their synthetic tidal gauge data. Perhaps you should make a habit of reading papers before you cite them (yes, I know they are paywalled, either use sci-hub, or contact the authors for a copy)

Reply to  tty
November 3, 2019 8:57 am


As usual, you comfortably stay on single examples, and deduce from them differing from what you guess be correct, that the whole paper is wrong.

What an unscientific approach!

“Perhaps you should make a habit of reading papers before you cite them (yes, I know they are paywalled, either use sci-hub, or contact the authors for a copy)”

I apologise, but here you behave really ridiculous. I carefully have read that paper (I got it from elsewhere just before the door unluckily was closed, so I couldn’t provide the link).

Why don’t you write a complete paper scientifically, irrefutably proving that Dangendorf & alii were wrong, and publish it, tty?

Why ?

Reply to  Bindidon
November 3, 2019 11:19 am

“you comfortably stay on single examples, and deduce from them differing from what you guess be correct, that the whole paper is wrong”

OK, in that case just where is the sea-level data from Port Hedland 1900-1965 (which it is not me that is guessing but Dangendorf et al).

And if you have read the paper and the supporting material you know that the R2 values for their “reconstructed” sea-level curves for those few sites that they present (9 out of 479) is in the 0.50-0.81 range, which is, to put things mildly, not very impressive. For New York for example it is 0.59, which means that their reconstruction explains less than 60% of the actual sea-level variation over the studied period. In any normal physical science results with an R2 < 0.9 wouldn't even be published.

By the way, I have written a number of “papers scientifically”, among other things on time series analysis of statistical data.

Nicholas McGinley
Reply to  Bindidon
November 3, 2019 1:33 pm

“Why don’t you write a complete paper scientifically, irrefutably proving that Dangendorf & alii were wrong, and publish it, tty?
Why ?”

This question implies that no one has done this, and that if someone did, it would make any difference.
They have, and it won’t.

Richard M
Reply to  Bindidon
November 3, 2019 8:59 am

1960 is an obvious cherry pick. More nonsense is all you have.

November 3, 2019 3:51 am
Reply to  chaamjamal
November 3, 2019 5:04 am

If I was building something, I would have just a smidgen more faith with a laser theodolite than I would have in satellite measurements.

Kurt in Switzerland
November 3, 2019 4:07 am

This sounded a lot like the propaganda promoted on our state-run media during prime time which I heard the other day… sure enough.

They even included a scary image showing the viewer how bad it will become in Amsterdam come 2050 if we don’t declare war on fossil fuels like the pigtailed child oracle from the North.

Funny how the headlines referenced [danger ahead, it’s worse than we thought for London, Amsterdam and Hamburg] yer their map of projected submerged European coastlines {at high tide & storm surge} actually hits a large chunk of Lincolnshire and some of Norfolk – whence our friends from E Anglia hail (rather than much of London per se), but the entire North Sea from Calais through halfway up Jutland, which includes the entire Atlantic coastlines of B, NL & D, plus some F & DK.

Anyway, they ‘forgot’ to actually point out the lack of any significant long-term acceleration in the sea level rise record when drafting their press announcement.


Kurt in Switzerland
Reply to  Kurt in Switzerland
November 3, 2019 4:32 am

Regarding the lack of an acceleration signal in the GMSL data for the 20th C, despite the massive increase in human CO2 emissions.

Read the last sentence from the abstract. A rare moment of unveiled candor? Note that Church & White are also co-authors of this paper.

Yet Church & White (among others) insist on promoting the belief that human CO2 emissions will cause an acceleration in sea level rise.
Trust us.
We’re scientists.

I noticed that the authors of the Climate Central funded paper featured in the WUWT post didn’t quote Benjamin et al in their bibliography, though they dutifully head-nod to the ‘consensus’ fear-mongering from the IPCC experts’ models of future sea level as a function of human CO2

Jeff Alberts
Reply to  Kurt in Switzerland
November 3, 2019 8:48 am

“Read the last sentence from the abstract. A rare moment of unveiled candor? Note that Church & White are also co-authors of this paper.”

How the hell did THAT get past the gatekeepers??

Kurt in Switzerland
Reply to  Jeff Alberts
November 3, 2019 9:39 am

Like I said, “perhaps a moment of candor” -dare I say “unabashed honesty”?

Can’t have been inadvertent – maybe it’s a Get out of Jail Free Card just in case the planet might start cooling / sea level rise rate were to not cooperate with the models or even slow down (oh the horror)!

Ed Zuiderwijk
November 3, 2019 4:22 am

Incorporating 23 variables? What does that mean? 23 adjustable numbers, 23 different input data?

And a discrepancy of 3.7 meter? What reference point in the carrying plane was used to estimate that? How accurate is the altitude of the flying LIDAR known? If they claim that it is a better method than that of the satellite based method they imply that the altitude of the plane is known to a better accuracy than that of the satellite’s orbit. That must be fractions of a millimetre. Really?

old white guy
November 3, 2019 4:39 am

Born on the east coast, worked on the west coast, vacation on the gulf of mexico and there has been no noticeable rise in the level of any of those bodies of water. Just an observation made over 75 years.

Reply to  old white guy
November 3, 2019 5:29 am

Good observation, OWG…my wife and I have owned a beach house for 20 years. During that time, the beach sand elevation had varied sometimes by two feet compared to “sea level” and the concrete breakwaters. This variation usually happens during a 2 day storm, and “unhappens” in a storm a year or two later. A mile further along the shore, if the sea level changed by half a foot due to CC, it would still be unnoticeable against the 100 foot cliffs, not to mention the 6 foot waves….Someday the sea may take it all, till then we adapt by adding a few boards to one end or the other of the pier. A microcosm of what must happen in the world at large… wonders if those concerned about a foot sea level rise per century have actually spent any significant part of their lives at a seashore.

Reply to  old white guy
November 4, 2019 5:22 am

Grew up on the mid-Texas Gulf coast. Anecdotally, water level definitely seems higher than I was a child. In the late ’50s/early ’60s, it was possible at low tide to walk (from Water St. in Rockport) out from the high-tide line for 50 yards on dry land. It has been decades since that was the case: the bottom never uncovers now — I would guess MLW level is at least a foot higher now than 50 years ago. Subsidence?

Hans Erren
November 3, 2019 4:46 am

A simple solution springs to my mind: use sea level gauges in coastal areas and do not use satellites at all.

Don K
Reply to  Hans Erren
November 3, 2019 6:32 am

“A simple solution springs to my mind: use sea level gauges in coastal areas and do not use satellites at all.”

That’s largely what is done in practice. Except that tidal gauges have a number of known problems — the worst being that the gauges are inevitably rising or sinking along with the land under them and probably any visible landmarks. Those elevation changes are not easy to measure with the precision needed to measure the current quite small changes in sea level. A second problem is that the tidal gauges are, of necessity, unevenly and rather poorly distributed, leaving vast expanses of the planet — e.g. the Southern Ocean — with nothing but satellite data.

In any case I think these guys are interested in demographic analysis — how many folks are potentially affected by flooding from the sea? rather than geophysics — how fast are sea levels rising? In that context, their paper may well have some merits. As far as information on how fast the seas are rising, the paper does nothing other than echo current (more likely than not nonsensical) “expert opinion”.

Hans Erren
Reply to  Don K
November 3, 2019 7:46 am

Gauges do exist where people are living and land subsidence can be accurately monitored using satellite radar.

Don K
Reply to  Hans Erren
November 3, 2019 11:48 am

You probably wouldn’t use satellite radar for a lot of practical reasons. Rather, you’d probably use GPS . And that is indeed what is being done. But you need a couple of magnitudes more accuracy (I’m not entirely sure how much) than you need from most GPS applications like controlling an unmanned tractor.

And there are other factors like crustal tides that require non-trivial corrections at the scale needed for accurately computing tidal gauge elevation changes for use in SLR computation.

I’m confident that good 0.1mm estimates can and will be obtained. Probably in the next decade or two? But I don’t think we’re quite there yet

Then there’s the problem that the earth’s seas aren’t really flat. And some distortions can be rather long lasting especially at the mm scale needed for SLR determination. Not just hours or days, but weeks, months, years and probably decades. Maybe centuries. So even if you know the elevation at tide gauges A and B “exactly”, the rate of sea level rise observed at the two locations can, and probably will be, different.

Satellite Radio Altimetry was supposed to solve those problems, but the differences between SLR computed from tidal gauges — around 2.0mm/yr — and that reported by satellites — around 3.0mm/yr — is bigger than expected. And no one really knows why.

Reply to  Don K
November 3, 2019 8:44 am

Don K

1. “Except that tidal gauges have a number of known problems — the worst being that the gauges are inevitably rising or sinking along with the land under them and probably any visible landmarks. ”

There are, near GPS processing as indicated by Hans Erren, techniques to compensate the effects of vertical land movement (not only GIA). All are used by professionals.

2. “A second problem is that the tidal gauges are, of necessity, unevenly and rather poorly distributed, leaving vast expanses of the planet — e.g. the Southern Ocean — with nothing but satellite data.”

2.1. Sorry for the trivial statement: the job of tide gauges is not to measure sea level rise among oceans: it is to measure it where they are.

2. Of course: ~1,500 gauges are not so terribly much for 1,200,000 km of coastal line! But the situation is not so desperate as you might imagine:

The historical predominance of some places is weakened by well known techniques (regionally specific weighting or distribution over a grid).

Reply to  Hans Erren
November 3, 2019 8:26 am

Hans Erren

“A simple solution springs to my mind: use sea level gauges in coastal areas and do not use satellites at all.”


Hans Erren
Reply to  Bindidon
November 3, 2019 1:04 pm

Yes sure.

Reply to  Hans Erren
November 3, 2019 5:07 pm

“Hans Erren November 3, 2019 at 4:46 am. A simple solution springs to my mind: use sea level gauges in coastal areas and do not use satellites at all”

Brilliant. Kind of like the emperor has no clothes. I will do a post on this and cite the Hans Erren comment. Unless Hans wants to co-author in which case, Hans pls leave me a reply.

Reply to  chaamjamal
November 3, 2019 6:47 pm

Hello Hans Erren
I included your comment in my post
please see paragraph #6 here

November 3, 2019 4:53 am

Synopsis: AI isn’t that much better at measurements than people.

John Dowser
November 3, 2019 5:01 am

About the lack of “AI code available to scrutinize for logic and coding mistakes.”

This wouldn’t be very useful as typical AI code builds, for example, something like a neural-network like matrix which acts like a black box. It’s not meant to be understood or read, analyzed by humans at all. And rarely there are tools to do so.

In other words, the only way to analyze it is by training exercises and analyze failure rate when a good comparison material exists. In this case however, there might be not enough different sets. From my own cursory view I’d say this application of AI feels rushed and not verified up to any scientific standard because of the “message” involved. And you see this a lot these days since AI “has the future” and climate might negate that future. A dangerous cocktail!

Jeff Alberts
Reply to  John Dowser
November 3, 2019 8:56 am

Is it REALLY AI? Or just more complex programming? I mean, is it learning and making its own decisions, reasoning?

November 3, 2019 5:01 am

In order for sea level to rise by 1 meter over the rest of this century, it would have to accelerate to a rate twice that of the Holocene Transgression (deglaciation)…

Sea level was fluctuating above the present level for most of the past 3,000 years during Neoglaciation….

Sea level abruptly started to rise at the end of Neoglaciation…

Sea level was rising just as rapidly during the early 20th Century warming period as it is now…

The fracking margin of error for even the satellite measurements is YUGE.

It’s even larger for reconstructions.


Anyone who publishes crackpot nonsense about catastrophic sea level rise in the 21st Century should be prosecuted for fraud.



Ron Long
Reply to  David Middleton
November 3, 2019 10:28 am

Hey David, amazing how the sea level in Holocene Transgression shows the Dalton Minimum (Little Ice Age). The Astro Climate crowd interprets the solar activity underway to indicate a Dalton (or Maunder?) Minimum. I wonder if they could hurry it along a little, us older guys want to be around to be able to say “I told you so”.

Reply to  Ron Long
November 3, 2019 3:45 pm

I have a better line: “Don’t you feel now like little nitwits?”

Reply to  David Middleton
November 3, 2019 10:40 am

Yes! If ExxonMobil can be dragged through the courts for what it knew about what hasn’t happened yet or never, then certainly scientist/ politicians/community agitators should be tried for lying about the data that actually exists.

November 3, 2019 5:03 am

Do any of these alarmists and warmunistas and their ilk have even the faintest idea about the properties of water?

Water is a unique molecule. It EXPANDS when it gets cold and gets even chubbier when it freezes.

“Most liquids have a quite simple behavior when they are cooled (at a fixed pressure): they shrink. The liquid contracts as it is cooled; because the molecules are moving slower they are less able to overcome the attractive intermolecular forces drawing them closer to each other. Then the freezing temperature is reached, and the substance solidifies, which causes it to contract some more because crystalline solids are usually tightly packed.

Water is one of the few exceptions to this behavior. When liquid water is cooled, it contracts like one would expect until a temperature of approximately 4 degrees Celsius is reached. After that, it expands slightly until it reaches the freezing point, and then when it freezes it expands by approximately 9%.

This unusual behavior has its origin in the structure of the water molecule. There is a strong tendency to form a network of hydrogen bonds, where each hydrogen atom is in a line between two oxygen atoms. This hydrogen bonding tendency gets stronger as the temperature gets lower (because there is less thermal energy to shake the hydrogen bonds out of position). The ice structure is completely hydrogen bonded, and these bonds force the crystalline structure to be very “open”….”
Link is here.
There are pictures, too.

So I’m just curious as to how some of this silliness passes inspection by anyone whose brain is actually working??

Smart Rock
Reply to  Sara
November 3, 2019 7:29 am

The remarkable property of pure water that achieves its maximum density at 4°C and then expands as it gets colder, doesn’t apply to seawater. The “negative coefficient of thermal expansion” disappears with increasing salinity. Sorry.

The coefficient of thermal expansion of water varies a lot with salinity, temperature and pressure. NASA estimates that “thermosteric” sea level rise (from thermal expansion) to be between 0.4 and 0.7 mm/year, but there are so many unknowns about the rate of warming of the entire ocean (or even if it is all warming and doesn’t have deep, cold layers that are still spreading cooling from the LIA) that this isn’t much more than a guess. We have to presume that NASA attributes the remainder of the SLR (which would be about 1 mm/year) to ice cap melting.

It’s quite possible that all the observed SLR is thermosteric and doesn’t contain components from Antarctic or Greenland melting. This would be the default position of “hard” skeptics.

Reply to  Sara
November 3, 2019 7:35 am

Oh no! Not again!

I think I have explained this a hundred times on WUWT.

This is only true for fresh water. Salt water just gets denser until it freezes at any salinity over 20 psu (Which means virtually everywhere except in some rivermouths and similar brackish areas):

comment image

Clyde Spencer
Reply to  tty
November 3, 2019 11:17 am

It is my understanding that when salt water freezes, it tends to exclude the salts, which drain downward as concentrated brines, and produce essentially pure water ice. There may be some bubbles and layers included, which makes the bulk composition less than pure. However, how does that behavior affect the volume question?

Nicholas McGinley
Reply to  Clyde Spencer
November 3, 2019 1:30 pm

The salt is forced out over time, not right at once.
Much of the salt is excluded in freshly formed ice, but it takes a few years until the water is mostly salt free.
The behavior of water as it changes in salinity and temp, and as it gets close to freezing, and then begins to freeze and finishes freezing, is amazingly complex.
Given the density curves, it is a miracle that sea water freezes from the surface down at all.
I have posted on this here and on Twitter several times, and can post links if you want to get into the full complexity of the specifics.

Clyde Spencer
Reply to  Nicholas McGinley
November 3, 2019 9:31 pm

Because I have conflicting demands on my time, I don’t really have the luxury of reading everything on the topic. If you could provide me with one or two links I’d appreciate it.

November 3, 2019 5:06 am

Hello Kurt in Switzerland November 3, 2019 at 4:32 am

the fear mongering in this case is not that sea level rise will be higher but whether the coastal high tide flooding events will be more severe at the same rate of sea level rise if the elevation of coastal lands is lower than our current estimate.

i hope this makes sense.
english is not my native language.

Kurt in Switzerland
Reply to  chaamjamal
November 3, 2019 5:39 am

Dear Chaamjamal,

You’re partly correct. The fear-mongering in the latest paper does indeed require a renewed statement of belief in ‘projections’ of future sea level rise. But you are correct that it is about the frequency of storm surges submerging the most vulnerable, low-lying settlements. This paper suggests that those places are more threatened than heretofore assumed the case, essentially 3x as bad (OMG), based on adjustments to the calculations of elevation above sea level of said land.

If you’re still in doubt, read the paper. It ‘trusts’ the models for future sea level rise.

Reply to  chaamjamal
November 3, 2019 8:09 am


Your english is very good.

If SLR is a serious problem, why “low lands” aren´t doing something to save their country? I see that it´s not a problem, because it would be very easy and cheap to build some walls to keep the sea out.
They do nothing because they know the truth. It´s just a new piece of propaganda.

Here in Finland people are also very worried that SLR is going to kill us all. They just “forget” landrising which is 6 – 11mm/year.

Nicholas McGinley
Reply to  F1nn
November 3, 2019 1:40 pm

At the rate of SLR, one average step for a human being every 100 years would easily allow anyone to outrun SLR.
Given daily and yearly tidal variations, erosion, the average interval between severe coastal storms for any given location, the length of time that a building on the coast is meant to last or will be replaced due to changing codes, lifestyles, and tastes, make the entire issue ludicrous.
There is photographic evidence from all over the world going back over 100 years. There are high water marks on rocks and structures in the water, and all sorts of other ways, including tide gages, to determine how much of a problem sea level rise is for people.
Interestingly, there exists not one single photographs that documents a noticeable rise in the level of the ocean in relationship to any building or other infrastructure, or even to rocks or other landmarks.

November 3, 2019 5:31 am

What do we know of the flexing of the oceans floors. Can we assume the bucket that holds the oceans waters has a fixed volume?

Don K
Reply to  RobK
November 3, 2019 7:46 am

RobK: Basically, we don’t know much about the flexing of the ocean floors. There is a field of study dealing with something called Glacial Isostasy. That’s the rebound of North America and Eurasia the continents after the transfer of huge amounts of ice back to the oceans at the end of the last glaciation. There is actual data on where and when old coastlines were. It’s not great, but it’s probably not awful. That data has been fit to a mathematical model of the Earth’s surface assuming that the weight of the thick icesheets displaced magma deep in the Earth into unglaciated areas and that removing that ice is causing the magma to slowly return. Not surprisingly, the model fit seems to be pretty good in the areas where we have data. Is the fit valid outside those areas? Not the way I’d bet, but what do I know?

Anyway, the model can be (and is) used to guess at changes in ocean floor geometry which are then used by the good folks at CU to fudge their satellite derived Sea Level Rise estimates upward by about 10%. I personally think that’s sophistry, not science.

You can read about it at

But they, and you, are certainly entitled to your own opinions.

Nicholas McGinley
Reply to  RobK
November 3, 2019 1:44 pm

We do not even have any idea of the flexing of the surface of the ocean over time, or even know the actual sea level away from the coastlines to within less that about 1 meter, because this is the resolution of the gravitational anomaly map of the Earth.
Minute physics, what is sea level (?) anyway:

November 3, 2019 5:39 am

Do you have a journal reference that explains for LIDAR transects and SRTM?

November 3, 2019 5:42 am

If You look for acceleration in trend lines these graphs are accurate ie change of change:

50 Year trend filter shows a periodic trend change all over the Globe.
Since 1870 .

Clyde Spencer
Reply to  Lasse
November 3, 2019 11:12 am

Those who prepare tide prediction charts are aware of nominal 20-year lunar periodicities in SL. However, those making forecasts rarely, if ever, take them into consideration when they show short-term ‘accelerations.’

Stuart Nachman
November 3, 2019 5:44 am

Don’t the numerous tidal gauge records, particularly in the USA document a fairly steady rise in sea level over the last century without any discernible rate of increase? I realize the limitations given land movement, but this may be the best evidence of what is actually occurring.

Kurt in Switzerland
Reply to  Stuart Nachman
November 3, 2019 5:58 am

And yes.

Reply to  Stuart Nachman
November 3, 2019 8:21 am

Stuart Nachman

“Don’t the numerous tidal gauge records, particularly in the USA document a fairly steady rise in sea level over the last century without any discernible rate of increase? ”


Above all, I notice that Americans always think that ‘what is good for the USA is for the rest of the Globe as well’, but… please compare the coastal line lengths:
– USA: ~ 20,000 km
– Globe: ~ 1,200,000 km.

Here is a graph indicating the sea level trend change in Church & White’s processing of sea level data:

The plot starts with the trend for 1880-2013, and ends with the trend for 1993-2013.

If there was no ‘discernible rate of increase’, as you seem to imagine, the plot would look like a straight line.

You may do the same analysis sing other evaluations, like that of Jevrejeva & al. for 1880-2009: there is no terrible difference.

Kurt in Switzerland
Reply to  Bindidon
November 3, 2019 9:33 am


Please explain how you reconcile your statement / graph claiming acceleration in GMSL vs time during the 20th Century with this paper?

Either one or the other is right, not both. I note that Church & White are co-authors to the Benjamin paper.

Reply to  Kurt in Switzerland
November 3, 2019 11:02 am

Kurt in Switzerland

It is not my job to reconcile anything.

I did nothing else than to look within Church & White’s original data, using a simple spreadsheet tool, at trends for periods starting at 5-year consecutive dates. That’s all.

The trend of the trend sequence calculated by the tool for 1883-1993 is 0.02 ± 0.01 mm/year².

That is twice as much as C&W report for 1900-2009. This ‘trend of trends’ method to compute a rate is far too simple, and thus I did not mention the result.

We are lay(wo)men here, and use simple thoughts and tools instead of performing deep mathematical analysis.

The question is: how significant is this rate, regardless wether 0.01 or 0.02 mm/yr² ? To answer, again is not my job.

J.-P. D.

Kurt in Switzerland
Reply to  Bindidon
November 3, 2019 4:34 pm

Jean-Pierre (or whatever your name is):
You are making stuff up. If Church & White ever presented such a set of tide gauge data as your plot suggests, it would be in a paper.

Looks to me like you’ve arbitrarily inserted what you’d like reality to be. The only way to get tide gauge data to reflect your fantasy would be massive tampering.

“It’s not my job” is a hilarious “run-away” cry. It suggests you are uncurious to a fault – a dyed in the wool warmist, perhaps?

Jeff Alberts
Reply to  Bindidon
November 3, 2019 11:32 am

Lots of smoothing going on there. Where are the error bars?

Reply to  Jeff Alberts
November 3, 2019 1:05 pm

Jeff Alberts

Smoothing ? What smoothing, Sir ??

Here is a sequence of linear estimates, drawn by a spreadsheet calculator as a sequence of straight segments:

1883-2013: 1,61 ± 0,01
1888-2013: 1,64 ± 0,01
1893-2013: 1,66 ± 0,01
1898-2013: 1,68 ± 0,01
1903-2013: 1,73 ± 0,01
1908-2013: 1,77 ± 0,01
1913-2013: 1,80 ± 0,01
1918-2013: 1,86 ± 0,01
1923-2013: 1,90 ± 0,01
1928-2013: 1,93 ± 0,01
1933-2013: 1,94 ± 0,01
1938-2013: 1,94 ± 0,01
1943-2013: 1,96 ± 0,01
1948-2013: 1,97 ± 0,02
1953-2013: 2,03 ± 0,02
1958-2013: 2,10 ± 0,02
1963-2013: 2,24 ± 0,02
1968-2013: 2,30 ± 0,03
1973-2013: 2,37 ± 0,03
1978-2013: 2,54 ± 0,04
1983-2013: 2,82 ± 0,05
1988-2013: 3,18 ± 0,05
1993-2013: 3,56 ± 0,06

Sorry: you wrote nonsense. Not unusual for eye-balling fans.
And… duh! This error bar syndrome is a bit boring, isn’t it?

Clyde Spencer
Reply to  Bindidon
November 3, 2019 9:40 pm


You said, “This error bar syndrome is a bit boring, isn’t it?” How could it be boring when it is such a novel concept to those who are easily excited.

If you aren’t dealing with error bars in your data, you are doing poor science.

Jeff Alberts
Reply to  Bindidon
November 3, 2019 9:49 pm

You’re making stuff up, so no, I didn’t write nonsense. You presented a smooth line from data that is far from smooth.

Reply to  Bindidon
November 4, 2019 1:50 am

Clyde Spencer

We are all lay(wo)men here.
Above all, Clyde Spencer, when I feel error bars necessary, I present them.

Reply to  Bindidon
November 4, 2019 1:59 am

Jeff Alberts

“You presented a smooth line from data that is far from smooth.”

There is here only one person ‘making stuff up’. The trend series plot is a sequence of STRAIGHT LINES, basta.

If you still don’t see them now, then I think it’s time for you to buy new glasses.

Reply to  Bindidon
November 4, 2019 10:25 am


I believe there is a problem with the data analysis you are presenting. Assume for a moment that SLR is acting on a long wavelength sine curve with the wavelength of 100 years or longer. Assume also, for a moment, that the peak of the sine wave is in the current time frame. If you then do a sequence of linear estimates as you have done here you get a same type of pattern. You get lower “average” slope at the beginning of the time sequence and much steeper (higher) values as you come into the present (and use shorter time periods to average over).

Now relating this to SLR, as most everyone acknowledges global SLR has been steadily increasing since the mid 1800s. If the wavelength of SLR is on a multi decadal or even multi century long time frame, then the presumed “acceleration” as you have sliced the data is just an artifact of nature of the sinusoidal form of the data, and not actual observations. You would see a steepness in the curve in that case as you move towards the present. Now add in several shorter wavelengths that act independent of the longer term ones (AMO? PDO? Something else we don’t understand yet?) and you can get even steeper curves that fit the hypothesis but are not based on the actual long term trends. Now just add a very longterm 1.8 mm/yr average and you gets a curve that long term actually shows only 1.8 mm/yr, but with “curve abuse” can show an acceleration that is a construct of just using shorter and shorter linear estimates as you move to the present day.

Bottom line: I do not believe your justification for dismissing the tide gauge data based on a second rate analysis of Church & White data stands up to even basic statistical rigor.

Clyde Spencer
Reply to  Bindidon
November 4, 2019 10:36 am


Your graph provides no error bars, when it is appropriate to provide them. You give the impression that the values are exact, which is not the case. You should also provide the Coefficient of Determination for the LSR segments if you are really interested in what is happening and what your calculations mean.

Is your graph a conflation of tide gauges in early years with satellite altimetry in recent years? If so, you should mention that. Do your points represent the beginning year or the mid-point of the segment. It appears to be the former. However, you should again document what it is that you are showing.

I think that you are clearly demonstrating that you are a “lay(wo)men.”

Clyde Spencer
Reply to  Jeff Alberts
November 4, 2019 10:22 am


You said, “We are all lay(wo)men here.” Speak for yourself! Not all here are lay people. I wouldn’t put myself in that category.

If you are truly a “lay(wo)men,” then how do you know when error bars are not necessary or appropriate? Just a feeling?

Reply to  Clyde Spencer
November 4, 2019 10:55 am

Clyde Spencer

I repeat: “… when I feel error bars necessary, I present them.”

And yes, Sah: about 99.5 % of the commenters posting here are all but professionals needing error bars. Is that too hard for you to understand? Jesus.

Clyde Spencer
Reply to  Clyde Spencer
November 4, 2019 9:15 pm

So, you are basically saying that you don’t care whether others think error bars are necessary. The only thing that is important is if you, the “lay(wo)men,” ‘feels’ you should use them. Delusions of grandeur!

November 3, 2019 6:14 am

‘Unfortunately, the AI bias correction was good but not great.’

So can it still be called Artificial ‘Intelligence?’

‘My only criticism of this first part is that the paper explicitly did NOT make the AI code available to scrutinize for logic and coding mistakes.’

I get the feeling that the use of the term ‘AI’ is puffery.

November 3, 2019 6:32 am

And the 2019 IPCC Special Report on the Ocean and Cryosphere1 in a Changing Climate (SROCC) touts the same sea level rise crises based on RCP models for 2050 and 2100.
Of course, the report ignores observed GMSL data trends which have a 0.95 correlation coefficient. They cherry pick out decadal trends and ignore longer term century trends. Even the decadal trends show a slower sea level rise than the RCP2.6 model.

Reply to  Renee
November 3, 2019 8:01 am


Sorry: this comparison is simply wrong.

This is a typical mistake: you compare the centennial estimate of C&W data with the 25 year estimate of altimetry data.

What you imho should have done instead is of course to compare C&W with SA within the same period, i.e. 1993-2013 (C&W was extended a bit by CSIRO since 2011):

You see the difference in trends: 2.6 mm/yr for NOAA, 3.6 for C&W for 1993-2013.

Some lacking knowledge argue it’s due to C&W having ‘mal’adapted their data to altimetry data.
Wrong again, and above all… disingenuous.

The increase in trend within C&W did not start with altimetry:

Mike McHenry
November 3, 2019 7:05 am

What has always intrigued me is how do you project Glacial ice melt due to air temperature? Glacial melt principally occurs due to the direct absorption of sun light from what I have read. Air has a puny heat content by contrast. Further complicated by the air ice interface. Does anyone know how they do the calculation?

john cooknell
November 3, 2019 7:11 am

Most of the UK flood mapping is based on LIDAR. It only proved that the Ordnance survey were exactly right 100 years ago.

Stripping back LIDAR to a bare ground model to negate the effects of built up areas and vegetation has exercised the flood mapping community for some time.

However once you get a bare ground model it doesn’t tell you which buildings will flood, as you stripped the building level information out.

The old maps are just as good as the new maps for emergency planning.

Taylor Pohlman
Reply to  john cooknell
November 3, 2019 7:32 am

Nice to be reminded what great engineers our ancestors were. I’ve often wondered if anybody today would tackle designing the Golden Gate Bridge with only slide rules…

john cooknell
Reply to  Taylor Pohlman
November 3, 2019 11:41 am

In the UK we do not need a model to tell us where we are.

Over 100 years ago the Ordnance survey worked out exactly where Mean Sea Level is relative to all our coastline. So please shove your model where the Sun doesn’t shine!

Geodetic levelling of the UK
Starting at Newlyn and working its way to every corner of England, Wales and Scotland, this process was all done manually using land levelling equipment. From this primary network, secondary benchmarks are set up and these are in turn used to level in the tide gauge pressure points, thereby referencing all tidal monitoring points to the same datum, and each other.

There were some extremely high and low waters at the start of the 20th Century, and I can find no explanation for this.

Taylor Pohlman
November 3, 2019 7:24 am

Any conclusions based on RCP 8.5 should immediately be round-filed, but I have a better idea. Peer reviewers should have forced the following statement in the Abstract: “probability of this paper’s conclusions being valid = Probability of RCP8.5 x Probability of WAIS collapse before 2100”. Since both values are vanishingly small, that would pretty much put this paper to bed…

Mike McHenry
November 3, 2019 7:43 am

I’ve concluded that RCP 8.5 was only created so academics and others could wite impactful papers.

Jeff Alberts
Reply to  Mike McHenry
November 3, 2019 10:12 am

Those wascally academics!

November 3, 2019 8:23 am

All the extrapolation curves shown use quadratic or exponential growth. In my paper (now corrected for typos)
I show that a sinusoidal curve is just as good a fit. In the paper the period of 770 years was just an eyed in guess and could have easily been a bit longer in line with the approximate 1000-year intervals between warm periods. Using a 1000-year curve points to an amplitude of nearly +/- 300mm with the next peak in 230 years at about 200mm above todays values. The previous minimum is shown as in about 1750 (mini ice age!?). The velocity based on the 1000-year curve is just peaking at about 1.6 mm/year and the acceleration has just turned negative. As discussed in my paper underlying velocities and accelerations are greatly changed over short time scales by decadal ocean oscillations (20 to 60-year range) that appear both in the Tidal and Satellite readings (see figs 14, 15, 23 and 24). These show up as residuals between actual measured levels and smoothed long-term trends as shown in Appendices 2 and 3.

Reply to  alankwelch
November 3, 2019 1:07 pm

The sinusoidal patterns are interesting in light of what I have recently been wondering about: changes in tides from year to year. This came up as a consequence of our boat club president commenting that there had been more 17 foot tides this year than in previous years, and the breakwater needed maintenance. A quick google search suggests about a 10 year period for fluctuations in tides.

I wonder if the tidal phenomena relate to the sinusoidal pattern in the residuals.

Reply to  Fran
November 5, 2019 6:36 am

There is a variation in lunation with a period of ~8,8 years and we are currently near the maximum so that may be the effect you are seeing.

Reply to  alankwelch
November 4, 2019 11:16 am

The sinusoidal curves are very interesting. Wavelet analysis of the Church and White global sea level reconstruction shows strong 18 yr and 50 yr periodicity pre-1940 and a weaker 50 yr and 20-30 yr periodicity post-1940.

November 3, 2019 8:26 am

I can make debunking these propaganda papers masquerading as science even easier. Take a moment to skim the abstract. If it mentions “climate models”, CMIP, or “carbon scenarios”, it’s using projections based on climate models and can be immediately rejected as unscientific. The models have been never been validated. They are grossly inaccurate when checked against observations. See, for example, this graph from IPCC AR5 (2013) highlighting how badly they overstate warming:

comment image

Any paper based on CMIP projections is a scientific sham, period.

November 3, 2019 8:58 am

Great analysis by Rud, as usual! Two additions..

(1). The ‘median K17/RCP8.5/2100’ scenario is not just extreme, but bizarrely unlikely. Using it as, in effect, a base case would be malfeasance in other fields. RCP8.5 is Somewhere between unlikely or impossible. Ditto for West Antarctica instability by 2050.

The odds of both by 2050 are microscopic. That this conclusion went thru peer review shows what a farce this has become for climate science.

(2). There are harsh words in the comments about AI. As people in that field say, “AI” is just cutting edge software. Once a method becomes widely used, people no longer consider it AI.

Also, the authors run rigorous validation checks on their methodology, and clearly state the resulting uncertainties. This is too rare in climate science. They should be commended for it.

John F. Hultquist
November 3, 2019 9:06 am

Thanks Rud,
… and ctm, and David M., and . . . others

john cooknell
November 3, 2019 9:19 am

A flood model is only as good as the actual flood you calibrate it to, there are so many variables, elevation is only one.

An uncalibrated flood model is of little use for planning anything, and if you wish you can just make things up.

Richard M
November 3, 2019 9:36 am

Not just “grossly inaccurate”, but anti-science nonsense. There is no science involved in climate models as we now can see from Frank 2019 and Thompson/Smith 2019.

November 3, 2019 9:56 am

People, please stop denying that ocean level is NOT rising at an alarming level, I have first hand experience. Just two weeks ago I went fishing off Newport Beach, CA, about 15 miles from the shore; the ocean level looked much higher, then it did three years ago( the last time I was out there) significantly higher. I’m encouraging all my friends and family to immediately abandon their beach front homes in Newport Beach, Sunset Beach and Mission Beach and move to higher ground; say Bakersfield, Fresno, Ridgecrest.
I had the same epiphany while I was flying over the Atlantic Ocean in my private jet; you look down and you can immediately see how the Ocean level has risen.

Reply to  Peter
November 4, 2019 12:02 pm

Genesis 9:11 God said. never again will I destroy the earth with a flood. What you need to concern yourselves with is the fire that will come one day.

November 3, 2019 10:42 am

A sure sign this paper will be used for mass media agitprop is that it is “open access”.
Expect wide fear mongering articles from the usual suspects…

Clyde Spencer
November 3, 2019 11:29 am

“… LIDAR transects, has only mapped the US and Australian coastal regions of those two wealthy countries.”

What is a wealthy country? It is one with abundant natural resources, particularly energy, and the infrastructure to provide its citizens with adequate and dependable inexpensive energy. The inexpensive energy allows the country to produce sufficient food and building materials so that its citizen’s needs can be met without shortages, interruptions, or exorbitant costs for essentials.

The way things are going, California may find that it soon will not meet that definition because of the costs of energy, taxes, and insurance rates. If the high tech companies start leaving the state for states with more reliable and affordable power, it will exacerbate the situation for those who can’t leave.

November 3, 2019 11:39 am

“The alternative much more accurate and expensive method, airplane flown LIDAR transects, has only mapped the US and Australian coastal regions of those two wealthy countries.”

Nonsense. How many densely populated coastal areas are there that have:

1. No accurate altitude data.
2. Are covered by dense forest.

Note that any area mapped by any other method than satellite altimetry is immune to this problem. That includes any area reasonably accurately mapped before c. 1990, which would include at least almost all of Europe, most of North America, Japan and coastal Australia.

Does anyone seriously believe that e. g. in Thailand they have no idea what the ground level is in Bangkok?

Reply to  tty
November 3, 2019 5:26 pm

The problem is that the authors of the paper have belatedly recognised that the satellite DEM that has previously been used was completely inadequate for the purpose. You are of course correct that virtually every coastal community uses much higher quality topographic data to measure levels, so have a very good understanding of the effects of inundation, whatever the cause, in their area. Photogrammetry from aerial photography has been providing accurate levels of urban areas for about a century now.

November 3, 2019 12:15 pm

This application of “AI” to inflate sea level rise sounds more like a mechanical Turk. An activist hiding in a box.

Taylor Pohlman
Reply to  Phil Salmon
November 3, 2019 7:50 pm

Phil, “Mechanical Turk”, “Activist in a box” sounds like Zoltar from the Liberty Mutual commercials – not sure if you’ve seen them, pretty hilarious.

November 3, 2019 1:01 pm

Here is Andrew Bolt’s interview with Daniel Fitzhenry a few months ago, concerning mean SLs at Fort Denison at Sydney Australia.
So far the BOM mean SL data shows it is lower today than in 1914. And Fitzhenry points out that it rises and falls by about 15 cm ( 6 inches) over the last 105 years.
The data is shown onscreen per decade up to 2019. How can these con merchants get away with so much of their deceptive nonsense?
Thanks to Bolt and Fitzhenry for telling us the truth.

November 3, 2019 1:22 pm

Here is the full Govt BOM data for MSL Fort Denison Sydney NSW since 1914. Note it is lower today than 1914.
Also most of the island states have more land area today than just 30 years ago. Looks like coral atolls haven’t changed much since a young Charles Darwin figured this out in 1836.
See Kench et al, Duvat et al studies etc. Here’s the BOM’s MSL data since 1914.

Reply to  Neville
November 3, 2019 3:08 pm


There are over 1500 tide gauges in the PMSL data set. Less than a half show negative trends, and the rest show positive trends.

PMSL station 196 aka Sydney, Fort Denison 2, shows (without VLM correction) a trend of 1 mm/yr over 105 years.

So what!

john cooknell
November 3, 2019 1:38 pm

In the UK we do not need a model to tell us where we are.

Over 100 years ago the Ordnance survey worked out exactly where Mean Sea Level is relative to all our coastline. So please shove your model where the Sun doesn’t shine!

Geodetic levelling of the UK
Starting at Newlyn and working its way to every corner of England, Wales and Scotland, this process was all done manually using land levelling equipment. From this primary network, secondary benchmarks are set up and these are in turn used to level in the tide gauge pressure points, thereby referencing all tidal monitoring points to the same datum, and each other.

There were some extremely high and low waters at the start of the 20th Century, and I can find no explanation for this.

November 3, 2019 6:07 pm

Link to their website:-

November 3, 2019 6:30 pm

In the audio ( ) at 1min40sec in Dr Ben Strauss explains the inaccuracies of the NASA satellite. He mentions the area of signal beam that NASA uses is some 30m diameter and therefore captures roofs etc sending back a noisy signal giving incorrect data.

Is that true? Surely NASA aint that dumb?

Then he says that they get their data from aircraft with pin point laser measurements. As a layman I ask, how accurately does an aircraft fly to know whether or not the land is going up or down or the aircraft?

Replies please.

J Mac
November 3, 2019 8:00 pm

Rud Istvan,
Thanks for the review and revelations. Much appreciated!

Robert B
November 4, 2019 12:43 am

“actual climate impact will be much worse because of population growth”

Kind of hints at the mentality of these activists. They just need to lead stupid people into the light (or away from the prime beach front property). You can’t expect them to have already started building new housing on higher ground.

Geoff Sherrington
November 4, 2019 1:11 am

In a collegiate spirit, might it be added that Judith Curry at Climate Etc did a rather thorough job of analysis of alleged acceleration a few months ago. It is hard for authors to make special pleading when the main evidence is so strong – but some diehards persist against the odds. However, the slow creep of the special pleading is becoming a worry. Geoff S

November 4, 2019 1:52 am

I lived on a beach side property in Melbourne, Australia for over 50 years, beginning in 1955. I mean my back gate was the beach.
I have seen the beach width alter many times over those years and I was there recently to scatter my late sister’s ashes.
You know what?
It is just the same. Someone might produce data that says sea level has risen and if so it is within the parameters of us sceptics!
More fear mongering carp!

November 4, 2019 2:17 am

Meanwhile, in the real world, much is known from observations about the effects of tides on coastlines. In the UK, this is the situation on the Eat coast in the county of Lincolnshire (I’ve lost the source reference for what follows, but there’s plenty about the British East coast on the internet):
Storm waves off the Lincolnshire coast are around 3 – 4 m in height with a 10 – 12 second period. The highest significant wave height was 3.5 m and recorded at Chapel Point. Chapel Point is the frontage that received the highest waves with the most energy. The highest waves in each year all occurred during March storms. The main wave direction is east to north-east with high storm waves coming from the north east. The gentle gradient of the near shore shallows reduces wave heights as they travel towards shore. Banks and overfalls are also features of the Lincolnshire bathymetry that modify incoming waves. The strong current system off the Lincolnshire coast is presumed to have the dominant effect on waves. The flood tide progresses south along the Lincolnshire coast and extends the wavelength of swell waves coming from the north. In turn, the ebb tide compresses the swell and counteracts the progressive energy of waves from the north. This leads to a steepening of waves, shortening the period and dissipating energy. This influence is combined with the energy loss and wave attenuation caused by the bathymetry. This means that despite a flood tide conserving energy, the stretched wavelength encounters the effects of bed friction earlier. The alongshore currents also cause wave refraction and it is presumed the dominant waves from the north-east will be directed to the south. Longer period waves identified in the peak period distribution plots and refracted waves may focus more energy and have a greater impact on sea defences and possible breach points. The tidal range is greatest to the south of Lincolnshire, and the highest tidal levels are shown to be at Skegness.
A dose of reality – waves up to 4m in height, contrast this with silly alarmist claims about millimetre rises in sea level due to CO2!

Reply to  Carbon500
November 4, 2019 10:51 am


Thanks a lot for these lines reflecting a reality you experienced. On this blog, such comments unfortunately are exceptions.

There will be a lot of places looking like what you describe, and lots of others showing the inverse:

I couldn’t find any UK tide gauge located around your Chapel Pointin the PMSL data set.
But there is for example CROMER

1632; 52.934361; 1.301639; CROMER'03.7%22N+1%C2%B018'05.9%22E/@53.8385498,-2.4996304,7z/data=!4m5!3m4!1s0x0:0x0!8m2!3d52.934361!4d1.301639?hl=en

which shows, for 1993-2013, a rise of 11 mm / year. That’s a little bit more than the worldwide average of all gauges for 1900-now (1.5 mm / year).

Still not that dramatic, but not necessary negligible.

Reply to  Bindidon
November 5, 2019 3:35 am

Thanks for your comments, Bindidon. Something I never see discussed is all the factors which affect sea level in a given locality. My own view is that ‘global’ doesn’t mean much. Factors such as erosion, silting-up, sediment transport, compaction, deep ocean sea bed changes and more all have an effect – yet it’s always CO2 that the alarmists and media bleat about!
The Lincolnshire coast as a whole suffers from sea erosion, and is regularly subjected to what’s called ‘replenishment’ – effectively building beaches up with sand pumped via giant pipes from elsewhere in the sea – my apologies if you live in the UK and already know this!
Cromer has its own complex erosion-related problems:
Subjectively, visit Cromer and it’s the same as it’s ever been – it’s certainly not in any danger of submersion from rising seas.

john cooknell
November 4, 2019 2:43 am

Studies like this show why Climate Science cannot be trusted. Their model is not applicable to the real world.

In the real world the ground elevation to mean sea level hasn’t moved, and we know where it is, we worked it out over a hundred years ago for anywhere that matters. We did it without airborne data, in fact the modern airborne data is checked for veracity against the manual record, and my experience is the airborne data is easily misinterpreted.

November 4, 2019 4:03 am

That historic tidal marker in Tasmania, … More detail at John Daley blog site.

November 4, 2019 5:34 am

“It then proceeds to model how many people end up under water.”

So, there’s a positive feedback at work – the more people who end up under water, the more sea-level must rise 🙂

Steve Z
November 4, 2019 10:23 am

We’re supposed to believe that a satellite method with a root-mean-square error of 1.8 meters (1,800 mm) will give us an accurate forecast of sea level over the next 80 years, when at 2.2 mm per year the rise over the last 80 years would have been only 176 mm, or less than 10% of the error?

Scientifically speaking, any measurement which is less than 10% of the error (or even 50% of the error) must be considered “indistinguishable from zero”. This article adds exactly nothing to the sea-level-rise argument. Or should we throw out all the tidal-gauge measurements and conclude that sea level is not rising?

November 4, 2019 11:02 am

4 new papers with one alarm-dispelling conclusion: future sea level rise may not threaten islands and reefs after all:

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