Current climate model simulations overestimate future sea-level rise


by Utrecht University, Utrecht University Faculty of Science

Credit: CC0 Public Domain

The melting rate of the Antarctic ice sheet is mainly controlled by the increase of ocean temperatures surrounding Antarctica. Using a new, higher-resolution climate model simulation, scientists from Utrecht University found a much slower ocean temperature increase compared to current simulations with a coarser resolution. Consequently, the projected sea-level rise in 100 years is about 25% lower than expected from the current simulations. These results are published today in the journal Science Advances.

Estimates for future sea-level rise are based on a large ensemble of climate model simulations. The output from these simulations helps to understand future climate change and its effects on the sea level. Climate researchers continually aim to improve these models, for example by using a much higher spatial resolution that takes more details into account. “High-resolution simulations can determine the ocean circulation much more accurately,” says Prof. Henk Dijkstra. Together with his Ph.D. candidate René van Westen, he has been studying ocean currents in high-resolution climate model simulations over the past few years.

Ocean eddies

The new high-resolution model takes into account ocean eddy processes. An eddy is a large (10-200 km) swirling and turbulent feature in the ocean circulation, which contributes to the transport of heat and salt. Adding ocean eddies into the simulation leads to a more realistic representation of the ocean temperatures surrounding Antarctica, which is key for determining the mass loss of the Antarctic ice sheet. “The Antarctic ice sheet is surrounded by ice shelves which reduce the flow of land ice into the ocean,” Van Westen explains. “Higher ocean temperatures around Antarctica increase the melting of these ice shelves, resulting in an acceleration of land ice into the ocean and consequently leading to more sea-level rise.

Comparison of the new high-resolution model (left) with the previously used low-resolution one (right). Credit: Utrecht University

The current climate model simulations, which do not take ocean eddies into account, project that the ocean temperatures around Antarctica are increasing under climate change. The new high-resolution simulation shows quite different behavior and some regions near Antarctica even cool under climate change. “These regions appear to be more resilient under climate change,” says Van Westen. Dijkstra adds: “One obtains a very different temperature response due to ocean-eddy effects.”

Full article here.

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April 12, 2021 10:18 pm

What idiot “climate scientists”! Doesn’t anyone own a thermometer anymore? We need a fleet of Argoes to surround Antarctica and take proper measurements! I can’t believe this article goes on and on about comparing the new model to the old – WHO CARES? How does it compare to Antarctica?

Chris Hanley
Reply to  PCman999
April 12, 2021 10:54 pm

There are Argo circum-Antarctic ocean temperatures showing no apparent trend from 2004:
comment image

April 12, 2021 10:43 pm

It’s like kids arguing who’s made the best/most colourful & accurate picture of a dinosaur they’ve never seen.
Where’s the real data ???
This is just more climate “séance”.

Reply to  saveenergy
April 12, 2021 11:07 pm

This is just more climate “séance”.

I love that. I will use it!

Izaak Walton
Reply to  saveenergy
April 12, 2021 11:50 pm

How on earth do you suggest they get “real data” about the sea level rise in 2100? Borrow
a handy time machine? You have to make predictions using a model. And the more accurate the model the better.

Reply to  Izaak Walton
April 13, 2021 12:41 am

But they have no idea if any particular model used is “accurate” or not.

Pretending ANY “climate model” has any accuracy at all over that sort of time frame, is in the realms of PURE FANTASY.

So just the thing Izzy-dumb would “believe” in.

Reply to  fred250
April 14, 2021 5:22 am

pure MANNTASY, rather than “fantasy”

Joel O’Bryan
Reply to  Izaak Walton
April 13, 2021 2:20 am

“Accurate” – I don’t think you know what that means in computer projection to the distant future.

Reply to  Joel O’Bryan
April 13, 2021 2:32 am

He can “dream” though..

Poor Izzy-dumb…his Mills and Boon fetish just keeps going !!

Nicholas McGinley
Reply to  Joel O’Bryan
April 13, 2021 2:30 pm

It means nothing…it is an utterly inane pronunciation.

Pamela Matlack-Klein
Reply to  Izaak Walton
April 13, 2021 2:53 am

To date, not one of the models used by the CAGW clowns has predicted anything accurately. They can’t even get their models to hindcast previous temps/sea levels accurately. There is no reason to believe anything they say. When it comes to sea levels, there is excellent evidence all over the world that attests for former sea stands. This is how we who actually go out in the field and LOOK know what former sea levels were. And we know how low they have been in the past also thanks to evidence that is brought up in dredges and fishing nets.

Models are nothing more than feeble attempts at fortune telling! This really should be evident to everyone by the long list of failed predictions over the past decades – England will no longer know snow….

Reply to  Pamela Matlack-Klein
April 13, 2021 3:04 am

“Models are nothing more than feeble attempts at fortune telling!”

I prefer to think of them as a sort of low-level computer game.

PacMan, Tetris etc.

Falling well short of those “civilisations” type sim games.

Reply to  Pamela Matlack-Klein
April 13, 2021 5:45 am

The current crop of climate models are random-number generators, within limits determined by a set of parameters. Only the parameters determine the models’ results. This model is no exception.

Nicholas McGinley
Reply to  Mike Jonas
April 13, 2021 2:32 pm

Exactly, and the people making up the parameters are just feeding in their own biases and then calling the results science.

Reply to  Pamela Matlack-Klein
April 16, 2021 8:25 am

Forget the models.
It´s already here.
Sea level rising is already very expensive, much more to come.
Take a look at South Florida.

Last edited 24 days ago by Herwig
Reply to  Herwig
April 17, 2021 5:35 am

You clowns are so comical it is painful to watch. Nothing is going to stop land subsidence in Miami, it is built on swamp land, idiot. I remember in the mid ’70s when visiting family there, neap tide would coincide with a close lunar approach and flood streets there. Storm surges flood the streets there, always have. Want to fix Miami’s flooding problem? Move it to higher ground, otherwise it will be as it has always been, flood prone. You are such a moron.

Reply to  Izaak Walton
April 13, 2021 5:29 am


Climate models have been in existence for decades.

The models have completely failed in all of their projections, which is why the model makers don’t call them predictions.

The models have not and cannot be validated.

Without validation the models are about as useful as chocolate fire guards.

Nicholas McGinley
Reply to  Redge
April 13, 2021 2:32 pm

In fact the previous prediction/projections, have falsified this entire approach.

Nicholas McGinley
Reply to  Izaak Walton
April 13, 2021 2:29 pm

If they cannot use a time frame that allows at least some sort of verification, what exactly is the point?
It is a useless exercise, devoid of science or even logical reasoning.

But we know why they are now making predictions on such a useless time frame: Because all of the predictions they have made that have ripened, have proven to be wildly inaccurate, even though they were made with unwavering confidence in their conclusions.

No one can possibly be dumb enough to think that such predictions reflect anything other than what the people making them decided will happen ahead of time.

pHil R
Reply to  Izaak Walton
April 13, 2021 3:31 pm


Nicholas McGinley
Reply to  saveenergy
April 13, 2021 2:20 pm

It is worse than talking about something no one has seen.
Dinosaurs at least were know to have existed.
These guys make a different model, and claim the model has “determined” the future!

“The output from these simulations helps to understand future climate change and its effects on the sea level. Climate researchers continually aim to improve these models, for example by using a much higher spatial resolution that takes more details into account. “High-resolution simulations can determine the ocean circulation much more accurately,” “

No, wrong. The output of simulations that are unverified and have never been useful in predicting anything, do not help anyone understand anything.
These jackasses do not know the difference between putting more effort into a prediction, and how likely the predictions are to come true.

Simulations do not “determine” a darn thing.
There is not even any trace of an understanding of basic logical reasoning from these people.

Nicholas McGinley
Reply to  Nicholas McGinley
April 13, 2021 2:23 pm

On top of that, they are making WAG’s on a time frame which is utterly useless, since everyone involved in the effort and everyone they are talking to will be long gone before then.
They might as well be making predictions about what happened prior to the Big Bang.
All it will ever amount to is hand waving.

April 12, 2021 10:46 pm

A search on “Antarctic ice loss” gets 5 million hits, and “Antarctic ice gain” gets 2.5 million hits. So the science is settled……

Reply to  DMacKenzie
April 13, 2021 5:20 am

Stoppit, you’ll be giving her ideas: Oreskes N. (2021) Science, submitted for publication.

April 12, 2021 11:15 pm

Ah yes, our favorite method of DOOM!, Sea Level Rise.
The chart shown in the video is small, but we can see it well enough to pick off some values using our Mark-1 eyeball.
2020 – 4 cm.
2100 – 34 cm.
Close enough.
In round numbers, 30 cm in 80 years from a standing start, so we calculate the all-important acceleration.
d = Vo + (1/2)*a*T^2

We take the initial velocity, Vo to be 0 as it is trivially small here, so:
d = 0.009375 cm/yr^2

And we can now calculate the *Rate* of SLR for the year 2100, after all that acceleration:
V = a * T
{Drum Roll….}
V = 0.75 cm/yr or 7.5 mm/yr.
Now we contrast and compare with the accepted overall rate currently,
1.8 to 2.2 mm/yr.
So these people are claiming about a 3.5x to 4.0x increase in the rate of SLR by 2100. Even though we have an outstanding SLR record going back well over 100 years, and without a trace of SLR *acceleration* anywhere.

But it gets better. Look at the video again, and they seem to be plotting SLR *acceleration* starting at 2000, or 2010 for sure. And this, we know is not happening from the tide gauge record.

My rating for this work: DOA – Dead on Arrival, model predictions contradicted by prior observation.

Reply to  TonyL
April 13, 2021 12:28 am

To carry on a bit.
Let us revisit the first equation, and put in an initial rate for SLR. As before, the generally agreed value is 1.8 to 2.2 mm/yr. So we can use 2.0 mm/yr.
This is a totally reasonable thing to do, as this is the SLR that is known to be happening. Again, we can use 30 cm in 80 years.

d = VoT + (1/2) * aT^2 (Notice I left out the first T in the eqn. above)

In this case a = 0.004375 cm/yr^2
And the rate of SLR in 2100 is 5.5 mm/yr.
Somewhat reduced, but still an increase of almost 3x.

Now we can watch the video full screen and look at the beginning of the graph, years 2000 to 2020. It does not look like there is any SLR there right in the beginning ten years. So it looks like they are not using an initial velocity.
OK, fine. Lets try this. We go from 2000 to 2100, and rise from 0.0 to 33 cm.
a = 0.00660 cm/yr^2
and SLR in 2100 = 6.6 mm/yr.

Right back where we started with a SLR over 3x what we have today.
Not even reasonable.

Thought for the day:
The authors run these climate models on computers so powerful that they are considered to be national strategic assets.
I check their work with a calculator. FUN!!!

Reply to  TonyL
April 13, 2021 4:46 am

Kind of reminds me of the early silicon valley days when Apple was using a Cray to model their second and third generation Macs, and Seymour Cray was using a Mac to conceptually design his next Cray

Reply to  TonyL
April 13, 2021 2:11 am

SLR was one few things alarmists have been able to quantitatively legislate.
Here in Victoria Australia, all developments must be designed to accommodate a 200 mm SLR by 2040.
The base was 2010, thus a required rate of 6.66mm/yr.
After 10 years of only 2mm/yr, they now need 9mm/yr to catch up.
The government is going to have real problems trying to backtrack this projection.

Reply to  Waza
April 13, 2021 8:40 am

Don’t forget how politicians work. When it is time to take “responsibility” the current batch of leftists will be gone.

Also remember that the media will ignore the ridiculous predictions of the past, re Paul Ehrlich. He still spouts his BS and media do not call him out. He thinks 1.5 to 2 billion humans is optimal for the Earth. If he thinks that, why is he still alive? Why did he have a child?

Proven wrong time and again, leftists will just move the goalposts. Fauci anyone?

Reply to  TonyL
April 13, 2021 2:45 am

… prior observation.

We have this recent WUWT story pointing to a study showing that it was warmer during the Minoan Warm Period and the Medieval Warm Period.

The alarmists insist that the warm periods and the Little Ice Age weren’t global. That gives rise to this:

Sea-level data for the Pacific Islands suggest that sea level in the region fell, possibly in two stages, between 1270 and 1475.


“in the region” … OMG. Even a clever six year old should be able to tell us that, aside from the land moving up and down (post glacial rebound etc.) the sea level rises and falls uniformly around the globe.

The sea level has been higher during the Holocene. Between the Holocene Optimum and now there’s no record of those higher sea levels causing any kind of problem. The change in sea levels was slow and easily adapted to. That also applies to the alarmists’ projected sea level rises.

Climate believer
April 13, 2021 1:09 am

“Current climate model simulations overestimate future sea-level rise”
I’d hazard a guess it’s not just sea-level rise.

Coeur de Lion
April 13, 2021 1:43 am

When it gets colder?

April 13, 2021 2:11 am

I compared the skill of climate models to reproduce the temperature trend in the Nino34 region. This region shows zero temperature trend over 4 decades. It becomes challenging for climate models to show a trend where there is none. Attached shows how a couple of the US climate prognosticators coped.

US groups demonstrate both options – ridiculous cooling of the past or ridiculous cooling of the present. Clearly either method is as silly as the other.

So tropical warm pools are thermostatically controlled to 30C and sea ice forms at -2C. Clearly there can not be much ocean warming until all the sea ice disappears- how is that going!

Reply to  RickWill
April 13, 2021 3:06 am

Nice comparison, Rick.. really shows just how INCOMPETENT climate models really are. !

Or as a modeller might say…… TOTALLY LACKING IN SKILL

Reply to  fred250
April 13, 2021 4:15 pm

I have challenged a couple of the climate prognosticating groups with this data. I was somewhat surprised that I got a response. Their initial response is that their model was similar to others and/or middle of the road. They could offer nothing but model output to back the results of their model – they live in model world. CSIRO did back away from their 314K by 2300 suggesting that their 308K figure for 2100 should be considered instead.

I have replied to the two groups so far contacted with the temperature regulating data from the moored buoys and no response yet.

The Nino34 region is highly scrutinised and will always be trendless given a few decades so is a good place to validate or condemn any climate model or temperature dataset for that matter.

April 13, 2021 2:58 am

I wonder how many of the models show that Greenland was 6 to 7ºC WARMER during the Holocene Optimum, when CO2 was apparently MUCH LOWER

“And at present, with the “summer SST ranging from 4.0-5.2°C,” we are likely experiencing some of the coldest temperatures of the last 10,000 years.

Last edited 28 days ago by fred250
Joseph Zorzin
April 13, 2021 3:30 am

The Guardian: “The climate emergency is here. The media needs to act like it”

“The planet is burning. It’s time for journalism to recognize that the climate emergency is here. This is a statement of science, not politics.”

a big duh!

Reply to  Joseph Zorzin
April 13, 2021 4:18 am

“Today, we are joined by others in the news industry, organizations that recognize that a global catastrophe is already here, and that without immediate action, it will get unimaginably worse.”


What sort of brain-dead zombie actually believes this sort of thing? All you have to do is get your nose out of your cell phone and look around.
When your population becomes even remotely susceptible to this drivel, then you know your civilization truly is doomed.

Reply to  Joseph Zorzin
April 13, 2021 5:29 am

The Guardian is using words like “burning” when France and the UK are having damaging frosts and late Spring snows. Their timing just might be a little off to persuade their readership of such. Even Australia is having an early taste of winter.

With the St Vincent volcano starting to pump SO2 into the lower stratosphere and lingering effects of the recent La Niña continuing to influence global temperatures, it doesn’t appear any global burning will be occurring until the western US fire season starts and we get the usual headlines associated with that. We also are having other explosive volcanoes stirring to life, including Mt Pelee and some in Iceland A perfect storm of these things going off will be a very bad thing for we humans if it happens.

Last edited 28 days ago by rbabcock
Joseph Zorzin
Reply to  rbabcock
April 13, 2021 5:58 am

I wonder if someone should take on the job of mimicking the alarmists but go further with the exaggeration- but do it so that it’s not so over the top that alarmists will immediately realize its sarcasm- just enough so that the average person will see how absurd it is. Of course this would need to be done by someone not known as a AGW skeptic.

Reply to  Joseph Zorzin
April 13, 2021 8:58 am

I’m not sure that’s possible. Many years ago I posted a picture that was distorted so that looked like the street and cars in Las Vegas were melting, and said “Global Warming melts cars in Las Vegas”

I had to spend a week convincing people it was a joke.

Nicholas McGinley
Reply to  Joseph Zorzin
April 13, 2021 2:43 pm

Over the top?
Like saying the planet is burning when we are living on planet in the midst of an ice age, in which a large portion of the surface is a perpetually frozen wasteland, and there is no place on Earth so hot that people cannot run ultramarathons there in mid Summer?

When nothing unusual whatsoever is happening in any place on the entire Earth?

Unimaginably worse than nothing happening, and nothing happening counts as a global catastrophe!
How exactly does one troll that?
Nothing they yammer on about has ever come true, and last month was no warmer than 40 years ago.

Besides, they are already themselves doing exactly what you suggest.
There is even a name for it, and Wikipedia pages on the subject.

Last edited 27 days ago by Nicholas McGinley
Clyde Spencer
Reply to  Joseph Zorzin
April 13, 2021 10:17 am
Tom Abbott
Reply to  Clyde Spencer
April 13, 2021 6:12 pm

From the link: “After over 175 years of publishing, Scientific American made a major editorial announcement on Monday: the historic U.S. magazine will officially adopt the term “climate emergency” for its coverage of the human-caused crisis.

The move came as part of a new initiative led by Covering Climate Now, a global consortium of media outlets dedicated to improving climate coverage. SciAm was one of the nine initial signatories of the Climate Emergency Statement.

Common Dreams is a member of the consortium, has signed on to the new statement, and has been using the term climate emergency in our reporting for several years.

Scientific American has agreed with major news outlets worldwide to start using the term “climate emergency” in its coverage of climate change. Read our statement about this decision, and the impact we hope it can have throughout the media landscape. . .

This idea is not a journalistic fancy,” writes a senior editor. “We are on solid scientific ground.”

end excerpts

So Scientific American and these other jokers are going to start claiming the world is overheating right this minute, yet a check of any regional surface temperature charts would show that region is in a temperature downtrend, not an uptrend.

So Scientific American and these other jokers are directly contradicting reality. That’s real good for a science publication.

I dropped my subscription to Scientific American a long time ago, about the time they started making unsubstantiated claims about the Earth’s climate overheating in their publication. I couldn’t stand that they were constatly putting forth speculation as representig facts. And they are doing the very same thing here. Nothing has changed since the 1980’s.

The science is not on solid ground. It’s all pure unsubstantiated speculation and has been since the 1970’s. These Scientific American people couldn’t prove Human-caused Climate Change is real if their lives depended on proving it because there is no evidence for it.

Scientific American has become part of the the Leftwing Propaganda Enterprise. Lending their authority to a lie.

Joseph Zorzin
Reply to  Tom Abbott
April 14, 2021 9:19 am

It’s supposed to snow this Friday in western Mass.

Tom Abbott
Reply to  Joseph Zorzin
April 15, 2021 7:27 am

Our usual last freeze date is about April 1, but it is still chilly around here and they are forecasting more cool weather although I don’t think we are going to get down to freezing. Kansas will, though. That’s not too far away.

Joseph Zorzin
April 13, 2021 3:35 am

“Climate researchers continually aim to improve these models, for example by using a much higher spatial resolution that takes more details into account.”

But…. that implies that the model fully incorporates all variables and their relationships correctly with the only missing factor bring that the resolution needs to be higher. No doubt many variables are missing and many relationships are faulty in the model. Fair enough- nothing wrong with making models as long as the weakness of them is acknowledged- but to pretend enough is understood to revolutionize our civilization with “green energy” at the cost of countless trillions is insane.

Robert Wager
Reply to  Joseph Zorzin
April 13, 2021 9:48 am

Every single model has a positive feedback variable. What if (like we find in nature) the feedback variable for climate is actually a negative value? I know, i KNOW, HOW DARE i?

April 13, 2021 3:40 am

The models are doing precisely what they are designed to do, perpetuate a political agenda.

Bruce Cobb
April 13, 2021 4:27 am

When Bad Science is walked back a little, you are still left with Bad Science. Just perhaps not quite so bad.

Tom Abbott
Reply to  Bruce Cobb
April 13, 2021 6:16 pm

Well, at least they are walking it back and it’s not “worse than we thought” this time. That’s an improvement.

H. D. Hoese
April 13, 2021 5:53 am

Have to see what Sverdrup thinks about this since they use his name in vain, both no doubt going around in big circles. Sverdrup, H. U. 1933. Vereinfachtes Verfahren zur Berechnung der Druck-und Massen verteilung im Meere. Geofysiske Publik. 10(1).
“The discrepancy between observations and models can be explained as follows…..In the ideal case, one would like to consider the subsurface temperature anomaly for each individual glaciers (e.g., the Pine Island, Thwaites, and Crosson glaciers). However, to resolve the ocean circulation near ice shelves, an even higher horizontal resolution is required [i.e., 200 m; (30)], which is about a factor 15 higher compared to that of the HR-CESM. Even if the temperature anomalies of each glacier is known, the corresponding response function is required and these are not available…..However, the results here already indicate that sea-level projections based on low-resolution climate models should be interpreted with great care, in particular, regarding estimates of the effects Antarctic basal melt. ”

April 13, 2021 7:26 am

Face it, getting the current climate models to explain the past is iffy at best, using them to predict the future is a fool’s errand.

Steve Z
April 13, 2021 8:25 am

If we assume that the sea-level data through 2020 on the graph were actually measured, we see about 2 to 3 cm sea level rise in 20 years, or up to 1.5 mm per year. Extrapolating linearly to the year 2100 would result in a maximum sea level rise of 15 cm (about 6 inches).

Why do the modelers believe that sea level rise will accelerate in the future, to arrive at 42 cm by 2100 (for the low-resolution model) or 33 cm (for the high-resolution model)? What would be the cause of this acceleration, which has not been observed over the last 100 years?

Even so, we can still remember Al Gore’s prediction of a 20-foot (about 610 cm) sea level rise in his “Inconvenient Truth” movie, while this latest model predicts only about 5.4% of what Gore predicted. Most likely, by the year 2100, the real sea level rise will be even less.

But by then, will our great-grandchildren have the good sense to discard these predictions as meaningless and get on with their lives, or will some of them be predicting disasters for the year 2200 in order to get research grants?

Alan Welch
Reply to  Steve Z
April 13, 2021 8:49 am

The modelers all seemed to have been from the school of Nerem in that they fit a quadratic equation to the known results over 20 years and then extrapolate for 80 years. Adding some pseudo noise makes it all look a bit more scientific – who would believe a smooth curve?

Being in engineering analysis for over 40 years if any engineer working for me insisted on doing this they would soon get their P45 (UK for sacking).

April 13, 2021 8:38 am

From the abstract:
“The HR-CESM and LR-CESM simulations are initiated from the end of the corresponding spin up and are forced under a 1% pCO2 increase each year (model years 2000–2100).”

Ergo: a science fiction input.

Pat from Kerbob
April 13, 2021 9:31 am

Personally i don’t care much about such modeling studies. The models are always high and SLR seems to be chugging along same rate as last 200 years.
All supposed acceleration seems to be related to either spliced satellite data and/or subsidence restricted by geography.
Isn’t there supposed to be a new satellite to check the old satellite which is promised to be even more accurate?
Or is that just finer resolution of garbage?

Am still planning my 60th birthday tour of places that were supposed to be long gone by 2025, always wanted to see the Maldives.

Do i need to put New Jersey on that list? Or will someone place a thumb back on the ground to the north to stop Jersey from tilting into the sea?

Clyde Spencer
Reply to  Pat from Kerbob
April 13, 2021 10:24 am

SLR seems to be chugging along same rate as last 200 years.

Try the last 7,000 years!

D. J. Hawkins
Reply to  Pat from Kerbob
April 13, 2021 1:08 pm

If you ask my wife, she’s all in favor of NJ sliding into the sea. I keep reminding her that we live there, but it doesn’t seem to move her opinion.

April 13, 2021 4:57 pm

Elementary Dear Watson-
Sudden Catastrophic Climate Events in The Past Had No Single Trigger. Here’s Why (
We must run everything on windmills solar panels and batteries.

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