ROYAL NETHERLANDS INSTITUTE FOR SEA RESEARCH
In their effort to provide decisionmakers with insight into the consequences of climate change, climate researchers at NIOZ, Deltares and UU are bringing order to the large amount of sea level projections, translating climate models to expected sea level rise. Their new overview study was published in the scientific journal Earth’s Future. “These results offer tools for decision making on the shorter and longer term.”
Aimée Slangen is a climate scientist at NIOZ and co-author of the IPCC climate report. Together with climate adaptation experts Marjolijn Haasnoot and Gundula Winter from Deltares and Utrecht University, both also IPCC authors, Slangen investigated the similarities and differences between the many sea level projections published in recent years.
Eight families
“We found that the set of more than 80 different projections can be reduced to eight ‘families’,” says Slangen. “Within each of the families of projections that we identified, researchers have often used similar data, but they have for instance used different model approaches. As a result, every new publication resulted in different amounts of projected sea level rise, depending on whether the publication focused on the shorter term or the longer term, or depending on the models used to estimate the processes causing a potentially large contribution of accelerated melting of the Antarctic ice sheet.”
These details are interesting for scientists, but make it more difficult for users to maintain overview. Slangen: “This can be an issue when you have to decide as a government what you are going to do to protect your coasts from rising sea levels. Decision makers can’t adjust their policies with every new publication.”
Half a meter rise before the end of the century
The researchers hope to dispel this doubt, as all families paint a similar picture for the first 50 cm of sea level rise. Slangen: “We will see the first half-meter rise before the end of this century, even if we start reducing greenhouse gas emissions on a large scale. For this period, it therefore makes little difference which family you use for sea level projections.”
According to adaptation expert Haasnoot, this therefore means that we can already start adapting to the consequences of sea level rise now. “Those who have to make the climate-proof decisions can already get started. However, it is important to take into account the uncertainty of the future. If you plan cleverly, you make sure that what you are doing now for a half meter sea level rise can be adjusted later for one meter. That will save a lot of money and effort.”
Models and emission scenarios
The larger the sea level rise, the more diverse the eight families become. Slangen: “From 75 cm to one meter sea level rise, it matters more which model approach you use and which climate scenario you follow. While such larger values are only exceeded in the long term, they can inform adaptation decision making already for the medium term. Each family is valuable for a specific situation and at what point certain threshold values are exceeded.”
Haasnoot : “In a vulnerable area, for example, you might choose a family with a large acceleration in the contribution of Antarctic melt. Many major world cities, such as London, New Orleans and Rotterdam, are in vulnerable areas. In such mega-deltas, relative sea level rise is even faster because of the land subsidence caused for instance by groundwater extraction.”
Flowchart
In their publication, the authors present a flow chart that policymakers can use when deciding when and how to adjust, while taking into account the range of uncertainty in sea level projections. “For example, the timing of these sea level values can be used to estimate until when a measure will remain effective,” says Haasnoot. But vice versa as well: given a desired lifespan, you can use these values to design a protective measure.
Slangen: “For the first 25 centimeters of sea level rise, the bandwidth of the timing is small: the projections show that this will happen before 2060. Half a meter rise will be reached before the end of the century. The larger the sea level rise, the larger the uncertainty. Depending on the family, 1.5 to 2 meter rise can be reached by the year 2100, but it could also be 2200 or later.”
DOI
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Rethinking Sea-Level Projections Using Families and Timing Differences
ARTICLE PUBLICATION DATE
30-Mar-2022
“Global mean sea level reached a new record high in 2021, after increasing at an average 4.5 mm per year over the period 2013 -2021. This is more than double the rate of between 1993 and 2002 and is mainly due to the accelerated loss of ice mass from the ice sheets. This has major implications for hundreds of millions of coastal dwellers and increases vulnerability to tropical cyclones.”
https://public.wmo.int/en/media/press-release/four-key-climate-change-indicators-break-records-2021
Still below the accuracy of the instruments.😂
When the satellite accuracy is +/-33mm it is still below the accuracy of the instruments. 4.5mm +/-33mm.
You’re getting your units wrong. It’s 4.5 mm/year. This means that your +/-33mm comparison is base free.
Not to worry. Pat Frank did the same thing in his functionally (thank the Imaginary Guy In The Sky!) uncited 2019 “Propagation” paper. As a data evaluator and statistician, he has a proud tradition of existence. Meaning, he has not manned up to his mistake(s) like Laura Resplandy. Don’t be like Dr. Frank….
Disfunctional families.
I’ve come in a bit late on this.
MGC’s graph of the Brest data looks dramatic but did he calculate the acceleration. The perception is all in the scales used.
The acceleration will work out at just over 0.01mm/year2. All of the long tidal data sets (over 150 years) show an acceleration of this order, which is a great deal lower than the so called “accelerations” from Satellite reading which is the source of most alarmist predictions.
All these calculations use quadratic curve fitting and to misquote JFK, “it is not because it is difficult but because it is easy”.
There are many other ways of curve fitting but the biggest mistake is in the use of extrapolation.
Definitely caused by a kink from level trend to positive trend around 1900-1910
So not human CO2.
As pointed out further up, Brest SLR is actually DECELERATING over the last 50 years.
And nearly all the satellite ” acceleration” comes at changes in satellite, often through adjusting previous data.
The sea level rise is currently about 3 mm / 10 years. In 100 years it will be 300 mm = 30 cm or 12 inches if everything continues as it is now. I think something will change by then, nothing is as regular as change!
Attaching a table of analysing the Brest Data over different time periods
Analysis of Brest Sea Levels
1850 to 2018 Slope = 1.3058 X2 Coefficient = 0.0054 “acceleration” = 0.0108
1850 to 1935 Slope = 0.0882 X2 Coefficient = 0.0221 “acceleration” = 0.0442
1835 to 201 Slope = 1.5591 X2 Coefficient = 0.0224 “acceleration” = 0.0448
1850 to 1892 Slope = 0. 0269 X2 Coefficient = -0.0360 “acceleration” = -0.0720
1892.5 to 1935 Slope = 2.3077 X2 Coefficient = -0.0594 “acceleration” = -0.1188
1935 to 1977.5 Slope = 0.5052 X2 Coefficient = -0.0283 “acceleration” = -0.0566
1977.5 to 2018 Slope = 2.6652 X2 Coefficient = -0.0162 “acceleration” = -0.0324
1850 to 1871.25 Slope = -1.2595 X2 Coefficient = -0.4504 “acceleration” = -0.9008
1871.25 to 1892.5 Slope = -1.5110 X2 Coefficient = -0.5387 “acceleration” = -1.0774
1892.5 to 1913.75 Slope = 3.1467 X2 Coefficient = 0.5480 “acceleration” = 1.0960
1913.75 to 1935 Slope = -1.1201 X2 Coefficient = 0.4905 “acceleration” = 0.9810
1935 to 1956.25 Slope = -0.2152 X2 Coefficient = 0.0168 “acceleration” = 0.0336
1956.25 to 1977.5 Slope = -0.3548 X2 Coefficient = -0.4453 “acceleration” = -0.8906
1977.5 to 1998.75 Slope = 3.4006 X2 Coefficient = -0.0163 “acceleration” = -0.0326
1998.75 to 2018 Slope = 2.5326 X2 Coefficient = 0.1322 “acceleration” = 0.2644
The full period gives an acceleration of 0.0108 mm/year2
The 2 half period each give accelerations over 4 times bigger
The 4 Quarter periods all give de-accelerations between 0.0324 and 0.1188
The 8 Eighth periods vary between an acceleration of 1.0960 and a de-acceleration of -1.0774.
That for a total period of 168 years. What chance does Nerem have with a period of less than 30 years for the satellite readings.
Why do you think limo libs like Obama buy million dollar estates on the water if they thought sea level rise was a concern? The answer is, they don’t. Climate change scare is for the peasants and useful idiots. Wake up folks.
The satellite data are global to be fair, not based at a single location.
Sorry – when Obama, Gore, Pelosi, and others all buy new beachfront property for millions of dollars – I do not buy that they believe sea level will rise to any appreciable degree in a hundred years. Seems like hokum to me.
The Gore and Obama properties are not truly “beachfront”. They are both a considerable distance from the shoreline. And the Pelosi story is just flat out false:
Conservative Media Makes Up a Fake Florida Mansion for Nancy Pelosi
Anatomy of a Viral Lie.
https://www.thebulwark.com/conservative-media-makes-up-a-fake-florida-mansion-for-nancy-pelosi/
Can’t make correct conclusions starting from false information, RRR.
So not beachfront properties?? Pictures, easy enough to find say otherwise MGC.
As to the Pelosi and/or Gore things, Rick Ray Robinson appears to have NOT verified for himself what he read in some news releases, you know, like about EVERY climate scare headline including those about “accelerating” sea level rise.
But you DID lie in your statement, “Obama properties are not truly beachfront”! Of course they are. Now the homes are not ON the sandy beaches, but BOTH properties go to the WATERLINE, and the Hawaii one even needs a seawall.
So there you are conflating true and false statements into one, just as R R R has appeared to have done. Pot, meet Kettle!
Hypocrisy is still hypocrisy, and when you consider the number of properties both ALGORE and Her Highness own, and the massive “carbon footprint” of same, what difference does it make whether they own beach front property, their massively ENERGY wasteful lifestyles say all there needs to be said about their “belief” in CAGW.
Drake, when I said “properties” I meant the houses. Sorry that I did not make that clear. As can be seen from the pictures you’ve provided, the buildings are a good distance from the water and are elevated.
1) Property is property. (“Can’t make correct conclusions starting from false (provided) information.”)
2) Look at the Hawaii photo … what the hell kind of a rationalization are you trying for. Given that level of self-delusion, it becomes apparent as to why you can hold the opinions that you hold without (yet) imploding.
3) “… good distance from the water and are elevated”. (Can’t make correct conclusions starting from false (provided) information).
4) The east coast Obama house is in the FEMA mapped flood plain. You are going to try a little harder to explain what you mean by elevated. That house was constructed without regard for current modeling, let alone future projections.
5) Liar, deluded, or both?
DonM
Can you really not see that high sea wall in the second picture?
And how much longer are the Obamas going to live? Maybe 40 years? How much will sea level rise in their lifetimes? Maybe a foot? The house is set far enough back for that.
Folks don’t seem to understand the real issue with sea level rise. Once set in motion, it will continue to accelerate and keep rising at elevated rates for centuries if not millennia to come, and will be almost impossible to stop later on.
The real issue is that we’re now pushing over the first domino in a centuries long chain of dominoes.
So, why can’t you just be honest in your discussion.
*Obama et al are hypocrites that don’t care what will happen after their lifetime(s). They are in it for now, but they claim (like you) that we all need to sacrifice for the common good.
*Yes, they are on the shore, and are directly subject to ocean events and changes.
*You think that the premise (or theory, if you prefer) of human influenced sea level rise is a real thing … and we need to sacrifice now protect others centuries into the future. You think that there is a tipping point and our current societies has the ability to tip the world into an accelerating SLR.
re: “You think that the premise of human influenced sea level rise is a real thing.”
Of course I do. So should anyone else who examines the scientific evidence in an unbiased, rational manner. Even Anthony Watts himself admits that human influence on sea level rise is real.
BTW, how is Obama a “hypocrite” for buying an already existing home? He did not build that home. Whatever sea level issues that may eventually arise for that building will occur regardless whether he bought that home or not.
re: “You think that there is a tipping point and our current societies has the ability to tip the world into an accelerating SLR”
Based on the available evidence, there is high confidence within the worldwide scientific community that the onset of “tipping the world into an accelerating SLR” has already occurred.
I’m stupid. And darn proud of it. I mention this only in the service of asking for patience when I ask stupid questions. Like this one: What is “relative sea level rise?”
Since the oceans are contiguous, sea level must be the same all over the world. That is, absolute sea level rise must be the same in Maine and Indonesia, surely. How can there then be relative sea level rise at all? The word “relative” implies a fraction. If the numerator (current sea level) is the same all over the globe, and then sea level rises (at the same level all over the globe) there is no relativity of sea level rise among different jurisdictions.
I have got to be missing something here, and I hope somebody will explain it to me.
“relative sea level rise” means sea level rise measured in relation to a local land reference. One way that “relative” sea level rise can differ from place to place is because the land itself can be moving up or down in different places.
Also, surprising as it may seem at first, “sea level must be the same all over the world” is actually not correct. The oceans are not like a quiescent bath tub. Because of differences from place to place in temperatures, winds, currents, and even gravity, absolute sea level (measured relative to the earth’s gravitational center) is not the same everywhere.
Hope that helps.
PS – I also hope “darn proud of it” is just joking around, LOL.