By Andy May
We are constantly told that the rate of global mean sea level (GMSL) rise is accelerating. Is it? How definitive is the evidence? If it is accelerating, why? Is the acceleration dangerous?
The usual assumption is that it is rising mostly because of man-made global warming and the melting of glaciers and the polar icecaps. Is that true? We will examine the evidence and see what we can figure out.
Dangendorf, et al. report that:
“We find a persistent acceleration in GMSL since the 1960s and demonstrate that this is largely (~76%) associated with sea-level changes in the Indo-Pacific and South Atlantic. We show that the initiation of the acceleration in the 1960s is tightly linked to an intensification and a basin-scale equatorward shift of Southern Hemispheric westerlies, leading to increased ocean heat uptake, and hence greater rates of GMSL rise, through changes in the circulation of the Southern Ocean.”
In absolute elevation, sea level is not the same in every ocean basin, this is due to the shape of the ocean basins, the individual ocean basin temperature, and in the strength and direction of the prevailing winds over the basin. Thus, the acceleration of sea level change in each basin is different, the global mean sea level is a combination of all the changes in each basin and just reporting (or discussing) GMSL masks a lot of complexity.
Dangendorf, et al. observe a persistent acceleration in global mean sea level since the 1960s and conclude that the acceleration is due to a shift in the prevailing Southern Hemisphere winds, not melting ice. In fact, they find that melting ice significantly contributed to the high rate of sea level rise in the 1930s, when greenhouse gas emissions were much lower than today, but had “zero to negative contributions to the acceleration coefficients between the 1940s and the early 1990s.”
They also report that the modern (1968-2015) acceleration in “global” sea level is not global at all, it is largely a rise in the acceleration of sea level rise in specific regions. No acceleration is detected in the eastern Pacific or the Arctic Ocean, and deceleration was detected in the Southern Ocean. Thus, the regions that should be most affected by melting ice, the Arctic and the Southern Ocean, show no acceleration.
This suggests that the currently observed acceleration is due to atmospheric circulation changes and not due to global warming or greenhouse gases. Major global wind circulation changes occur with a period of about 65 years and these cause changes in global temperatures as shown in figure 1.
While the AMO Index is not exactly the same as the 60-70-year global climate oscillation, usually called the climate stadium wave, it is similar and the AMO is an important component of the stadium wave (Wyatt M. G., 2012c) and (Wyatt & Curry, 2014). Notice that the AMO shows a minimum between 1910 and 1925 and between 1970 and 1980 and that these minima approximately coincide with lows in the HadCRUT4 global average surface temperature after it is detrended.
Various estimates of sea level rise are shown in figure 2, including the Dangendorf et al. estimate.
The first thing we notice in figure two is that from 1900 to 2000 all the long-term rates of sea level rise are reasonably linear with rates between 1.4 and 2.0 mm/year or 5 to 8 inches per century. The second thing we notice is there is a similar cyclical pattern of increasing and decreasing acceleration of sea level rise in all the reconstructions. All show acceleration from about 1920 to around 1950-1960, followed by deceleration to the early 1990s, then acceleration again after the 1990s. Coincidentally, the satellite record begins as the cyclical acceleration starts up in the early 1990s.
According to Dangendorf et al., the acceleration in the rate of sea level rise observed since the 1960s (near the peak of the cycle) is not significantly larger than the acceleration noticed in 1920s and 1930s. It seems likely that the natural climate pattern seen in figure 1 is heavily influencing the sea level rise acceleration in both periods of acceleration. A comparison of the acceleration from 1960-2016 to that observed from 1920 to 1950 is shown in figure 3 for the Dangendorf hybrid model and the Jevrejeva tide gauge reconstruction.
In figure 3 it is clear that the Jevrejeva sea level rise record is much more detailed and less processed than the complex hybrid Dangendorf reconstruction, but both show similar rates of acceleration for the respective periods. The largest rate of acceleration is the Jevrejeva rate for 1920 to 1950 and the smallest is the Dangendorf rate for the same period. The modern Dangendorf rate of acceleration is modest and smaller than the modern Jevrejeva rate.
As noted in Dangendorf, et al. the rate of acceleration in the 1920 to 1950 period is similar to the rate in the modern period and the Jevrejeva data from 1920 to 1950 suggests the acceleration in that period was higher than the modern period. Since the early 20th century rate of acceleration was probably unaffected by greenhouse gas emissions there is no reason to believe the modern period of acceleration is any different.
Greenhouse gas emissions from 1950 to 1990 were higher than from 1920 to 1950, yet the acceleration of the rate of sea level rise was lower then and possibly negative, as shown in figure 4.
The very heavily processed Dangendorf et al. sea level record shows a low rate of acceleration from 1950 to 1991, but the Jevrejeva tide gauge record actually shows deceleration over the period.
Discussion and Conclusions
There are specific breakpoints in climatic trends at around 1912 and 1972 as seen in the AMO Index in figure 1, these breakpoints can also be seen in the detrended HadCRUT4 global mean surface temperature record. For more information on climate breakpoints, aka climate shifts see here, here, and here.
Breaks also occur in the rate of sea level rise as shown in figure 2, but they are shifted slightly to about ±1928 and ±1991. All the sea level rise records in figure 2 show these breakpoints, with varying degrees of clarity.
It is unclear why the climate changes at these times, or if the changes are related to the changes in the rate of sea level rise. This is an area that needs more research. But these plots suggest that the acceleration of sea level rise changes on a cycle of 60-70 years. The changes follow a similar pattern to the rate of changes in the global surface temperature and the Atlantic Multidecadal Oscillation.
Dangendorf et al. believe that the 20th century changes in the acceleration of sea level rise are tightly linked to changes in atmospheric circulation, especially circulation in the Pacific and Southern Oceans. We see no reason to disagree with this opinion. Changes in the acceleration of sea level rise do not appear to be related to greenhouse gas emissions or human activities.
What if there are no periods of slowing acceleration, or any actual deceleration in sea level rise in this century? In other words, what if the current naturally “juiced” rate of acceleration since 1960 continues to 2100? How high would global mean sea level rise? Table 1 does that calculation using the data for each global sea level reconstruction discussed in this post. The functions used in the Jevrejeva and Dangendorf calculations are given in figure 3 on the left side. For the other functions used see the supplementary spreadsheet linked at the end of this post.
As Table 1 shows, if the observed acceleration since the most recent upswing around 1960, in each reconstruction, is extrapolated to 2100 the sea level rise is only 16 to 33 inches. This is less than the global average daily tide and not a problem for anyone. The naturally juiced acceleration since 1960 is very unlikely to continue to 2100, it should swing back to a slower acceleration soon, just as it did sometime between 1955 and 1965.
A spreadsheet with the data used to make the figures and table can be downloaded here.
Download the bibliography here.
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GMSL — YAMGA, yet another meaningless global average
Disagree a bit. Allowing for differences in regional Earth gravity, water seeks its own level always. Bathtub principle applies, so a global average is legit—unlike a global average temperature even when expressed as anomalies. Reason is that temp is an intensive rather than extensive metric, so not mathematically legitimately averaged. (Translation, temp is a function of heat content, so intensive, while water level is a simple function of gravity, so extensive.)
I do agree; the big problem is the measurements — at any single location, is the ocean rising? Or the land sinking? And can these tiny changes actually be resolved?
Gotta stop Gilligan from moving the post farther out into the lagoon to anchor his crab traps
Rud,
I agree with Karlomonte. Sea level varies all over all the time due to wind, tides, and water temperature. The mean sea level varies for every ocean basin. The GMSL is a guess, and even if close to the truth, is only a snapshot in time. It is also meaningless since sea level varies regionally as the prevailing winds change. See Dangendorf, cited in the post.
You cannot think of at least one meaningful application of the GMSL?
No, I cannot. The only meaningful measure is local sea level and that is only important to the local community. GMSL is a meaningless measure, the rate of sea level rise or fall varies by huge amounts from one place to another and from one ocean to another. Changes in the local tidal range are more significant.
Do you think a water mass increase would not also increase GMSL?
Do you think an OHC increase would not also increase GMSL?
Do you think a GMSL increase would not also increase local sea levels?
Do you think a GMSL increase would not reduce land area?
Andy already remarked above, “No acceleration is detected in the eastern Pacific or the Arctic Ocean, and deceleration was detected in the Southern Ocean.” Apparently, your implied unexamined assumption that GMSL will increase all local sea levels is wrong.
Inasmuch as most tide stations don’t differentiate between SL rise and local subsidence, we don’t have a good grasp of what GMSL means with respect to land area.
Let me ask you a question: Do you suppose that the crust below the oceans basins is immune to the loading of additional water and that there won’t be an isostatic adjustment in the underlying mantle, leading to a rise in the elevation of the land surrounding the basin?
That has nothing to do with my question.
I never said that any increase in GMSL necessarily implies that all local sea levels also increase. That is your argument and yours alone. And as I often have to tell people…don’t expect me to defend your argument especially when they are absurd.
I absolutely do NOT think the crust below the oceans basins is immune from the loading of additional water. I’ll even go further and say I know with near certainty that the removal of solid H2O mass from land and its conversion to a liquid in the ocean basins results in isostatic rebound of the land. This line of discussion, however, is irrelevant to the discussion of whether GMSL is meaningful and useful. It is certainly an interesting line of discussion, but here it only serves to deflect and divert away from the topic of whether Andry truly believes GMSL is meaningless which I stared here in this subthread.
I interpreted your question, “Do you think a GMSL increase would not also increase local sea levels?,” as a rhetorical question, implying that you believed it would. Was I wrong? If so, what was the point of your list of questions?
Yes. The application is to scare the population. That is “meaningful.”
Do you think GMSL is so technically meaningless that if we added up all of the ice on Greenland and Antarctica and calculated a GMSL increase of 65 meters that we would not be able to conclude that more locations would be underwater?
You are going well beyond the scope of this post. I have dealt with your other issues in other posts, use this link to look for what you are asking about. Here, please stick to the subjects discussed in this post:
Search Results for “sea level” – Andy May Petrophysicist
The scope I’m responding to is this exchange.
The intent of my questions is to get you think about more deeply about the GMSL. Do you truly believe there is no meaning in the GMSL at all? Going further do you truly believe there is no meaning in any global average, sea level, temperature or otherwise?
Yes
Fair enough. So how far do you go in the interpretation of your position here? Does this extend such that global average metrics cannot be used for hypothesis testing? Does this extend such that predictions of those metrics are automatically invalid? Does this extend such that those metrics cannot be used as inputs in other models? Does this extend such that the application of the mean value theorem for integrals of a function defined on those metrics is invalid? I’m just curious how committed you are to this position?
Andy, don’t respond to bdgwx’s questions. He has a habit of misrepresenting people, like he does with Monckton by discrediting him based on a casual quote from 2013.
Do you think linking to someone’s past predictions is “misrepresenting people”?
If it’s no longer their position, then yes, absolutely:
And more interestingly, I counted 17 comments you made in that very thread.
This guy is so obsessive that he keeps detailed lists of “errors” that “contrarians” have supposedly made, that go back years. A contrarian (his word) is anyone who dares to question his kooky ideas about technical subjects.
Let me remind you of the context.
You said: “Nobody, including Monckton, knows for sure when the warming will stop”.
I said “That hasn’t stopped WUWT from publishing articles claiming just that. See here, here, and here for examples. And I’ll remind you of the prediction Monckton published in 2013 saying the Earth was going to cool by 0.5 C.”
And don’t think the irony of you lecturing me about misrepresenting others simply because I linked to content relevant to something you said while simultaneously defending Monckton’s argument that the IPCC over-predicted warming when, in fact, they may have actually under-estimated the warming went unnoticed.
Anyway, back on point…
Do you think Andy’s position that global averages like sea level and temperature are meaningless even to the extent that after probing for anything at all that could be meaningful he held firm is a justifiable position?
Do you think Andy publishing an article saying “The planet is no longer warming” has merit given that he thinks the global average temperature is meaningless?
Oh Please. Stop claiming that the sky is falling.
Where I live the sea level dropped 1 foot in 17 seconds because of an earthquake as evidenced by mussels on pier pilings. Everyone knows mussels live underwater, even in 1906 when people noticed the same thing had happened. Those seismic events negated any sea level rise for hundreds of years.
I didn’t say the sky was falling. I’m asking Andy if he truly things global averages, whether it be GMSL, GAT, or otherwise are meaningless.
I’ll you the same question I asked Spart Nova 4. Do you reject the idea, on the grounds that it is meaningless, that an increase in the GMSL by 65m would necessarily mean that land area decreased and that more areas would be underwater?
Averages are sometimes useful. However, they tend to hide detail that might lead one to misinterpret the situation. They have to be used carefully and appropriately. From my perspective, averages, particularly without their associated standard deviation and kurtosis, are commonly abused.
That’s an interesting take since considering a specific spot also hides detail that might lead one to misinterpret the situation. For example, take the Arctic Ocean which Dangendorf et al. 2019 say has not experienced any statistically significant sea level rise since 1993. You might erroneously conclude that there was no water mass increase or thermal expansion of the ocean as a whole during this period.
That is true of any metric.
Sure. But that doesn’t mean averages aren’t meaningful and useful. And besides non-averaged metrics are also abused so let’s no pretend that just because a metric can be abused that it isn’t meaningful or useful.
Argumentative Fallacy – Red Herring. Proves nothing.
One would not expect that based on the global average, which suggests a rise everywhere. That is exactly my point about averages hiding details.
Is your hypothesis that the only way for an average to go up is if all constituent components that went into that average also went up?
I ask because if that is your hypothesis then I can work with you on mathematical proof that falsifies it.
You’re about as genuine as a three-dollar bill.
Oh dearie me… beeswax is off in it own little fantasy la-la-land yet again. !
I’ll ask you a different question. Do you expect that you or any of your relatives, friends, friends of relatives or anyone else alive on the earth today to still be alive when your GMSL increases by 65 meters?
If so, then make the prediction of when it will happen. If not, then stop worrying. It’s not your problem to solve.
I’m happy to answer. No.
If you wouldn’t mind can you answer me question…Do you reject the idea, on the grounds that it is meaningless, that an increase in the GMSL by 65m would necessarily mean that land area decreased and that more areas would be underwater?
Like I said, no, but I’ll make a prediction anyway. The consilience of evidence constrains the lower bound to about 5000 years.
Things that are not happening and are totally unlikely to happen is many thousands of years, if ever.
YES…. TOTALLY MEANINGLESS. !
More like about 3X that the last time I did a back-of-envelope calculation.
If this is in reference to the time it takes to end the ice age then I’m more than willing to consider a higher lower bound than 5000 years. Just keep in mind that the tighter you make the range the more evidence you need to justify it.
Argumentative Fallacy – Red Herring. Proves nothing.
IF there were 65 m of water-equivalent depth added to the oceans, the rise would not be equal everywhere, and there would probably be few if any locations 65 m below the surface. It is also improbable that all the ice in Greenland and Antarctica will melt under any reasonable scenario of human influence while anything resembling modern humans are still extant. All the ice didn’t melt during the Eemian, and modern humans building cities have only been doing so for about 10,000 years.
Even if fossil fuels are responsible for warming, which I doubt, there is a limited supply, which will force us to develop alternatives. If warming is the result of humans, it is a temporary problem that will fix itself. If we aren’t responsible, then mitigation is the only option available to us.
Of course it’s not going to be equal everywhere. But it’s also not going to be <= 0 m everywhere (or anywhere for that matter) either. If the GMSL increases by 65 m then we can eliminate broad swaths of possibilities for what local sea levels might look like just from first principal reasoning alone. It is an indisputable fact that you can draw conclusions about how GMSL modulates local sea level and how local sea level modulates GMSL. Therefore the GMSL is both meaningful and useful. So when I see people say that cannot think any way at all that the GMSL is meaningful I question the conviction of that position.
Don’t heat what I’m not saying. I’m not saying GMSL or any average is the be-all-end-all metric. I’m not saying that GMSL is the only metric needed to understand spot sea levels. I’m not saying GMSL is the only metric needed to analyze sea level in general. I’m not saying the sky is falling. I’m not anything of things and many others things that some may desperately have wanted me to say.
You are not saying anything…. except total gibberish !!
Translation please, anyone?
If your Precautionary Principle deep dive justifys ceasing all fossil fuel use right now because of some future waming causing sea level rise, then what does the Precautionary Principle indicate we should do right now to mitigate the next glaciation?
Talk about meaningless and totally irrelevant…
… Look at your own comments !
How accurate is the 1810 1860 data? If correct those fluctuations in such a short time frame are impressive.
Attached is Jevrejeva, et al. (2008) plot of the standard error for the whole series. The reference is in the bibliography. The errors are pretty large until the late 1800s.
And as is all too frequently the case in climatology, there is no associated uncertainty envelope provided for the annual/monthly GMSL or the regression lines, by the various authors. The numbers are treated as though they are exact and have as much precision as the authors want to assign.
Sea level also varies with the barometric pressure of the air masses moving over the oceans, and it is rarely paid attention to except when the eye of a hurricane passes over the land/water interface and contributes to exceptional flooding as the water rises under low atmospheric pressure.
They live and die by the misnamed Standard Error of the Mean.
Disagree. Simple example: Panama Canal. A series of locks are needed to keep the higher ocean from flooding through and to allow ships from the lower ocean to be raised in steps so they can sail in the higher ocean.
Gatún lake is 26m above sea level. The locks are needed to get ships on and off the lake that crosses most of the distance. The builders of the canal chose not to excavate the entire canal down to sea level because of the difficulty of such an approach. As it is, the current drought is making it difficult to keep enough water in the lake to allow bigger ships to pass.
luckily no islands nearby that could tip over and capsize.
Rud claims
Not doesn’t, as evidenced by sea level differences across the panama canal. It takes more time to settle than happens between changes such as evaporation, rain and tides.
Re: Gatún lake
Ok, fair call.
WUWT had an article which showed Graphic Charts of SLR according to tidal gauges from many places around the earth, and none of them showed accelerating sea level rise. I tried to find that article, I thought I bookmarked it, ….anyone here have a link to that WUWT article? It was probably two years ago.
Colorado University’s Sea Level Research Group C-SLURG says the rate of acceleration since 1992 is 0.083mm/yr² Here’s a chart below, for 25 years of acceleration (1992-2018) from 208 tide gauges that shows that it’s inconclusive. Calculation was done via (V2-V1)/2 not the best way to do it, but easily done on a Microsoft Excel spread sheet.
Here’s a distribution chart of acceleration for 67 tide gauges done with Excel’s 2nd order polynomial (quadratic function)
From Excel, jmp and MiniTab experience, polynomial fits are dangerous because you can fit anything to a polynomial with enough trail-and-error. Not many models fit long-term data if an exponent is bigger than 2.
If one is not paying attention to the error envelope, it is easy to over-fit the data and end up with something that is only applicable to that particular data set, and not have general applicability.
The typical equation from Excel’s “Display Equation on chart” function looks like this one from Brest France (annual data)
I appreciate that acceleration has occurred since the early 1990s and don’t argue that point. The question is if the acceleration is due to human greenhouse gas emissions or melting ice? It seems very like the answer is no.
As noted in the post, it appears likely that the acceleration is due to a natural climate cycle that hit a low in the rate of sea level rise in the early 1990s (see figure 1). The cycle is about 65 years, so we are now at the cycle peak and slowed acceleration or even deceleration is likely over the next 30 years.
Further, Dangendorf, et al. found that a change in the prevailing Southern Hemisphere wind patterns are likely responsible for the acceleration since 1991. It has nothing to do with ice melting.
Ocean warming is a factor since it causes ocean expansion and sea level rise. But greenhouse gases do not warm the oceans much, the IR they emit cannot penetrate the ocean surface, right? Only sunlight penetrates. Thus, the ocean warming we see is due to the modern solar maximum and reduced cloud cover which reduces reflected sunlight.
1). The cycle is about 65 years, so we are now at the cycle peak and slowed acceleration or even deceleration is likely over the next 30 years.
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That’s about what I get, see below:
The ocean transfers almost all of the energy it receives from the sun to the atmosphere. The small residual causes the ocean to warm. The atmosphere cannot significantly warm the ocean through IR radiation, but it does regulate the heat flux from the ocean to the atmosphere through evaporation, which depends on wind speed and atmospheric temperature. Thus, by reducing this heat flux, the atmosphere can easily warm the ocean even if the solar energy input is constant.
The observation that the ocean is warming does not tell us what is causing it.
What about a more active sun and Earth’s declining magnetic field strength ? More energy deeper in the oceans something CO2 never can do.
Andy, I’m looking at figure 1 and I’m seeing 3 full cycles – peak to peak from about 1850 to 1950, trough to trough from 1915 to 1975, and peak to peak early 40’s to (I’m guessing) 2030. Or periods of 100 years, 60 years, and 90 years, Say an average of 83 years. Where does the 65 year period come from?
I eyeball ~1930 to ~1990. Most easily seen in Jevrejeva, but also in C&W and Dangenddorf. Also, I see ~1860 to 1930.
But this is a very subjective look. I’d like to see some more analysis, but I don’t think the data are accurate enough or long enough to be definitive.
The cycles in surface temperature, SST, and AMO average about 68 years, but they are offset from these.
“But greenhouse gases do not warm the oceans much, the IR they emit cannot penetrate the ocean surface, right?”
Not right, the IR does penetrate the surface and is very rapidly absorbed by the sea water.
Absorbed IR will be reradiated or lost via increased evaporation.
It causes the water temperature to rise, a requirement to increase radiation or evaporation.
“the IR does penetrate the surface”
I guess if you think “penetrating” means a tiny tiny fraction of a mm !!!
red thumb thinks IR penetrates more than a tiny fraction of a mm.
Learn some basic physic , idiot !!.
Penetrating in this case means entering the water where it can be absorbed, the reflection coefficient from air to water is very low so virtually all the IR penetrates the surface where it is very rapidly absorbed and warms the surface layer.
Dude, to penetrate anything but a minimal distance, the H2O molecules at the very surface would have to become saturated yet remain in place. What happens is that they evaporate and take the heat with them exposing the next layer of molecules.
You might look up latent heat and how it affects temperature. While you are at it look up heat of vaporization.
Are you saying you don’t think DWIR impacts the energy budget of the ocean or are you are saying you don’t think the energy budget of the ocean impacts its temperature?
BTW…IR does penetrate the surface of water. In fact, water so greedily takes IR that most of it is absorbed in the first few millimeters.
Yup. That’s why every coffee shop in the world uses IR radiative heating from above to heat their water and to keep their coffee pots hot. Because it is so greedily efficient they would be foolish to use a 1500 watt heating pad from below. 420 ppm CO2 IR radiation is in fact causing the oceans to boil. Just ask António Guterres about the global boiling.
I’m skeptical. A 1500 watt hot plate would almost certainly impart more energy to a pot of coffee than a traditional food service heat lamp. Ignoring for a moment that 1500 W for a coffee pot hot plate would be on the high end you have to remember that the 1500 W is almost entirely delivered to the cup. Contrast this with typical 500 W heat lamp stand. The view factor at the cup if mounted 12″ high would be about 0.1 (and that’s being generous) yielding only 50 W. So I’m not seeing why a coffee shop would want to choose heat lamps over hot plates here. And yes, I understand that you were being sarcastic so most coffee shops do not, in fact, use heat lamps. Heat lamps are more widely used in the food service environments.
OMG we have a fool that heats his water from above with hot air !
Basic physics, totally ignored. Hilarious.
Incredible.,
NON-credible .. would be a more apt description of its posts.
Indeed — right up there with his nonsense about oven doors, but incredible that my eyes are seeing these bizarre claims.
There was a very accurate measurement experiment done, (can’t find the link)
But it showed that low-level IR caused the top fraction of a mm water to evaporate, which cause the water in the next couple of mm to actually COOL !
Evaporation does that.. or were you totally ignorant of that fact .
You are comparing conduction to radiation? Not a good scientific practice.
Beeswax has proven many times that it hasn’t got a clue about the different methods of heat transfer.
Which is where evaporation takes place!
Do you think that means that IR cannot warm water?
beeswax , ignoring basic physics, yet again..
The scientific understanding of a squashed slug.
I don’t honestly know the answer to that. However, I believe that IR would more likely lead to cooling because of the induced evaporation.
Did you do the experiment?
Have you observed the results of the countless experiments performed everyday with food service IR lamps?
Again showing you are totally ignorant of what food service lamps are used for.
Hint, little slug, they are not used for cooking the food.
That is exactly what you don’t want them to do.
That is done in enclosed ovens or heat from underneath.
As I said above, the scientific understanding of a squashed slug.
How can evaporation be induced without raising the temperature?
They do not need to penetrate much, they just need to reduce the outgoing surface flux. The solid earth is opaque to radiation beyond a few microns as well, yet no one takes any issue with sunlight warming granite.
The surface evaporates from heat below due to heat absorbed from the sun. IR from above is only going to increase evaporation by providing more energy. BTW, what is the hot body (surface or CO2) and cold body (surface or CO2)? Where does CO2 receive its heat from?
The evaporation will increase because the temperature is higher because there is more energy, so in a roundabout way, yes.
The net flow of IR is always from the surface to atmosphere to space. CO2 absorbs emitted IR from the surface and atmosphere.
It’s the University of Colorado.
AM, have covered your topic several times before.
Steve Case does a good job with random long record sites—similar to Jerejeva and Church, but less selective so more objective.
My best estimates were in long ago guest post here ‘Sea level rise, acceleration, and closure’. The ‘best’ (meaning vertical land motion via dGPS corrected) long record tide gauges per Nils Axl Moerner gives 2.2mm/yr SLR, and no acceleration in the past century.
The importance of that estimate is that it closes exactly with the sum of ARGO estimated steric rise plus satellite estimated ice sheet loss over the past decade.
Thanks Rud,
The main reason I wrote the article was the analysis in Dangendorf, et al. I don’t agree with everything in the article, but their real addition to climate science was they showed that the recent acceleration in sea level rise (since 1991) could not have been due to melting ice. This was new, at least to me, and their case is very convincing. Combine that with the fact that greenhouse gas radiation cannot warm the oceans much, and you see that humans had nothing to do with the modern acceleration.
I thought that idea was worth writing about. It is an important point.
AM, agree. Well done detail.
”you see that humans had nothing to do with the modern acceleration.”
That’s the scary part. We know that nature can do very nasty stuff.
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NOAA’s Tides and Currents page says:
“… the absolute global sea level rise is
believed to be 1.7-1.8 millimeters/year.”
Doesn’t say anything about acceleration.
Good for them. Someone in a conference room might have said “I don’t know”.
Thanks for the interesting comparison of the science, Andy, but as someone who has been involved in building jetties and sea-walls to specific sea levels since 1946 and who still checks many of the existing ones at Highest Astronomical Tides, on the east coast of Australia I have yet to be convinced there is any sea level rise at all, let alone acceleration.
I have yet to be convinced there is any
sea level rise at all, let alone acceleration.
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This web page
https://psmsl.org/data/obtaining/
doesn’t lie.
Possibly, Steve, but there is only one way SL gauges go over the years, and that is down.
It’s called gravity.
Always exaggerates any SLR.
There are lots of tide gauges that have negative rates of sea level rise, and that’s because the shore they sit on is rising. However, whether the tide gauge is rising static or falling over time, acceleration if there is any remains constant see my graph of rates of acceleration for 67 long term tide gauges above: LINK
This is a good example of why a global mean sea level is meaningful and useful. Given an increase in the GMSL and application of the mean value theorem for integrals we can conclude that the ocean volume increased. OTOH, if looking only at a specific site, say with a negate rate of sea level rise, you might erroneously conclude that ocean volume decreased.
This post is a good example of how little understanding you have of basic metrology.
“ we can conclude that the ocean volume increased.”
NO, you cannot.
You have zero idea what else might have happened under the oceans.
A few cm uplift over a large area of the Pacific ocean floor could easily account for all of the very slight sea level rise.
Continents moving together and apart could also be the cause.
Without highly accurate mapping of all ocean basins, we have no possible way of knowing.
And to pretend that ocean floors are not moving, is just utter and complete ignorance.
The only place sea level really matters is at the ocean/land interface.
That means tide gauges, which Steve Case shows have insignificant acceleration on a very small rate of sea level rise.
The sea surface level measured in the middle of vast ocean expanses, far away from land, is totally unimportant.
And to pretend that ocean floors are not moving, is just utter and complete ignorance.
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Another nugget for my files (-:
By the way whether a tide gage has a positive or negative rate of sea level rise, a lot or not so much, the acceleration rate is much the same over those variables.
Hmmm, on edit, it looks like I said that already
I agree. bdgwx has cherry picked another piece of math. The mean value theorem simply says in a continuous function the is an interval whose mean is also the mean of the function. Whoop de doo! Where is that interval? Is it a symmetrical function or distorted. Does one side have a slow rise and the other a high rate.
The oceans are not cups with a uniform bottom. The earth isn’t a real sphere either. You just can’t say, here is the center of this ocean and land points equidistant from that point should have the same height.
Yeah, he didn’t watch the video, pity, might have learned something.
spangled,
The rate of sea level rise is very tiny, and the observed global acceleration is even tinier. To be sure both are below the accuracy of our measurements. It is only if we assume that our processing of the measures of vertical land movement and sea level around the world are accurate (we can’t know that) that we see any rise or acceleration at all.
But, if there is an acceleration since 1991, Dangendorf’s explanation of why is very interesting and credible to me.
Can you define “very tiny”? In other words what is the highest possible sea level rise rate that still qualifies as “very tiny”?
0.1 mm/yr^2 is very tiny by any definition. You can’t even see it.
_______________________________________________
In a mere 10 years that would bump up the rate a millimeter per year. Dr. R Steve Nerem of University of Colorado’s Sea Level Research Group CSLRG claims a ridiculous acceleration of 0.083mm/yr² which would bump up the rate an additional millimeter per year in 12 years.
You can do the arithmetic to figure out how fast the rate of sea level rise would be by 2100. There’s a reason why I say Dr. Nerem’s claim is ridiculous.
On edit, I guess you meant 0.01mm/yr² or less.
Is 0.1 mm/yr^2 the highest possible acceleration rate today?
What is the rise in mm/yr which is what I was actually asking about?
Around 1.5 to 2mm/year SLR is obviously VERY SCARY to you.
Most people who have lived their lives on the oceans/shore interface, would not have noticed any difference.
Why do you choose to lock your ignorant little mind in chicken-little fantasy mod?
Get back to reality, and all your moronic panic will disappear.
Yes Andy. So tiny that the first monthly mean sea level [always the best way to measure SL] taken in Sydney Harbour in 1914, is ~ 7 inches LOWER than the average monthly MSL of the1300 months since.
Sorry Andy, that should read HIGHER, not LOWER. And here is the link:
http://www.bom.gov.au/ntc/IDO70000/IDO70000_60370_SLD.shtml
I’m amused with NASA sea level rise maps showing the greatest rise in deep oceans away from coast lines. I wish they would do a comparison of their measurements to each tide gauge location so accuracy of their satellite techniques can be verified.
Sea level changes have so many causes including:
Glaciers melting or increasing ice
Ocean temperature changes
Ocean and wind currents
Land subsidence or uplift
Building dams or drying lakes/seas
Etc…
With so many components impacting sea level, long term forecasts cannot be made with simple linear or acceleration formulas based on recent trends.
I have always wondered what role all the sediments brought by rivers play. If we look at old seabeds now transformed into mountains and we see miles deep layer after layer formed by sediments .
And water extracted from aquifers.
A video to make one think about the difficulties in getting a GMSL can be seen at:
https://www.youtube.com/watch?v=q65O3qA0-n4
In this, one metre accuracy is claimed as the limit of such a figure
The 1m accuracy is for the EGM84 Earth Gravitational Model at a spot location; not the GMSL.
The sea level is calculated from the difference between the average ocean surface level and the altitude of the satellite. The speed and altitude of the satellite is calculated based on a model using the EGM84. That implies that the altitude and position(?) of the satellite is only known to +/- 1m in the open ocean. Yet, they are claiming to know the change in SL to fractions of a mm when the altitude is +/- 1m! They certainly aren’t measuring the same point every time, and even so, the surface is continually varying. Thus, SL doesn’t meet the criteria of being ‘stationary’ to justify teasing out more precision.
Can you show mathematically using the law of propagation of uncertainty what the problem is specifically?
Can you present another estimate of the uncertainty of the GMSL so that we can compare it to that of Dangendorf et al. 2019?
Can you?
The rule of thumb for subtracting numbers with different significant figures is that significant figures beyond that found in the least precise operand should be discarded. That is, the precision of the difference of the altitude and distance to the water surface is only justifiably expressed as +/-0.5m, which means units of meters only, where the +/-0.5m is implied by the unit meters.
I’m addressing your statement…“Yet, they are claiming to know the change in SL to fractions of a mm when the altitude is +/- 1m!”
Dangendorf et al. 2019 is claiming fractions of a mm uncertainty for the change in GMSL; not for the sea level at a specific location. I’m asking you to show via the law of propagation of uncertainty how an uncertainty for the change in GMSL (not for a spot value) below ±1m is mathematically impossible and then present a figure that you feel is correct.
Now you are weaseling again, you don’t understand uncertainty AT ALL.
Ok, Assuming the altitude is ±1 meter then any reading must carry that uncertainty.
GMSL is made up from “specific locations”. Consequently, it must be an average of sea level measurement from various points on the globe.
Let’s just make up some MSL numbers.
9, 6 -4, 2, -3, 8, 2, -1, 5, 3 ==> all ±1 meter
(9 + 6 + -4 + 2 + -3 +8 + 2 + -1 + 5 + 3) / 10 = 27 / 10 = 2.7
(uc(y) / 2.7)² ≈ (1/9)² + (1/6)² +(1/-4)² + (1/2)² +(1/-3)² + (1/8)² + (1/2)² +(1/-1)² + (1/5)² + (1/3)² ≈ 1.88
uc(y) = 2.7 ∙ √1.88 = 3.7
we’ll expand that by a factor of 1.96
3.7 ∙ 1.96 ≈ 7.3
So the shortest coverage interval at 95% is ≈(-4.6 m, 10 m)
See the following for a description of calculating uncertainty.
Measurement Uncertainty:
A Reintroduction
Antonio Possolo & Juris Meija
Volume of a Storage Tank, Page 13
And guess what I got using the NIST Uncertainty Machine?
Population
Mean = 2.7 SD = 4.2
Interval -5.5 to 10.9
k = 2
Sample
Mean = 2.7 SD = 4.4
Interval -5.9 to 11
k = 1.9
He don’t need no significant figures, for him all data is 100% accurate because everything is random and cancels.
That is why you can not average a quantity of measurements and say you know the mean to more resolution than what you measured them.
Significant Figures Lab | General Chemistry Lab News (middlebury.edu)
Significant Figures (mit.edu)
Microsoft Word – Document3 (purdue.edu)
1.3: Measurements, Uncertainty and Significant Figures – Physics LibreTexts
These are all universities. Anyone who doesn’t agree with these lab instructions will need to supply references that contradict them.
bwx (along with bellman et at.) have discovered how to defeat these rules — they are smart.
They THINK they have! Anyone trained in the physical sciences know these rules and follows them. People who do not follow these rules can never provide counter examples from university lab sciences nor are they believed by people familiar with physical science.
Their position reveals what profession has taken over climate science, mathematicians/statisticians who are not trained on physical measurements.
I am surprised we have not seen temperature estimates in the realm of 10⁻⁴ although we do see uncertainties in that value. Without significant digit rules, how does one make a consistent and logical decision on the number of decimal places to include in a calculation of temperature?
From Purdue:
From MIT:
Which is what you must do with recorded integer temperatures when calculating anomalies.
They use the same false theory as climate science that averaging can add precision to measurements. If I take enough measurements, I can divide by the √n and add umpteenth decimal places to the measurement. Doesn’t matter if the measurements have a resolution of ±1 m or ±1°C. Heck if I measure the speed of light with a stopwatch enough times I can develop the speed to the 10⁻¹⁰.
Don’t forget that bwx uses the NIST Uncertainty Machine to “prove” this.
He doesn’t even understand that the various x₀ to x₁₄ in the Uncertainty Machine are individual parts of a relationship. Like “length · width · height” or “π·r²·h”. That means it only allows fifteen unique measurements to be used to calculate a measurand. That means x₀ = length, x₁ = width, x₂ = height. Defining a measurand as an average of 30 individual measurements isn’t allowed in the Uncertainty Machine. In other words, if I had a surface area made up of 30 sides, the Uncertainty Machine wouldn’t have the capacity to calculate the measurement uncertainty.
His approach to learning technical subjects is to scan for loopholes that might reinforce his kooky ideas.
Time to fess up, you didn’t even watch the 3-minute video.
The current sea level is measured using satellites. The satellites circling the earth then compare annual change in sea level to determine the rate of change.
All very simple stuff.
The difficult bit, is how do you calibrate the satellite position?
A further difficulty is how accurate is the measurement and how does that innate system accuracy compare with the variation in acceleration being sought?
The short YouTube video posted by John in Oz, details some of the factors involved that make measuring sea level difficult. The video doesn’t get into one of the greatest variants affecting sea level though, which is local weather.
The sensible folk around the world have been familiar with sea level measurement difficulty. They decided the only valid option (for them) was to place a local tide gauge at the jetty. From that simple but consistent level gauge it is then possible to say what is happening locally to sea level which is all that actually matters.
The NASA data is clearly interesting, but not too significant to local fisher folk etc.
One other point of note but of little significance is the moon. Our tidal generator is moving away from Earth at about 12ft/century. (3.7cm/year). It does remind us the tides we experience are not fixed in perpetuity either.
When I did a deep dive into how the satellite position was determined I was disillusioned. The individual readings could vary substantially due to inaccuracies in determining GPS triangulation. Up to a meter if I remember correctly. Why so much? Variations in gravity as the earth is circled lets the orbit change a lot.
Guess how they obtain a quoted accuracy? Same as climate science. They average readings over a month and as near as I could find calculate an uncertainty of the mean by dividing by the √n. These readings are just like temperature, never the same thing twice. At best, the quoted uncertainty should be closer to a meter than just a few cm’s.
Jim, when I read the info re calibration of the satellites I was surprised they were able to claim an accuracy of a few millimetres. I believe the satellite datum points are a couple of lakes in North America.
I am sure the lakes never vary in height or have any wind deviation and the tidal forces moving the land up and down as well as the water surface will of course be so easy to accommodate and enable accurate calibration.
I recall thinking it was like suggesting someone using a twelve inch rule can measure accurately to within one thousandth of an inch, if the measurement is taken often enough and averaged.
I am not convinced.
The daily variances from tides are routinely ignored.
Any undergrad with a little statistics can tell you that regression results are only valid over the range of the data.
Climate science cannot understand the difference between averaging multiple measurements of the same quantity versus averaging thousands of measurements made with different instruments of varying quantities.
1/root(N) is their god.
And, there is the issue of “mascons’:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JB011547
Based on some of the reactions here, sea level rise is another sacred cow of the trendologists.
How do the satellites deal with waves and tides?
Average them away!
They “pretend” they can average them out… which is, of course, more fantasy la-la stuff.
Was there ever a moment in time when Nature allowed all the seas to conveniently lay themselves flat level so that a clever human could judge how meaningless knowing global sea level would be in terms of whether it is standing still, going up, down or simply crazy everything at the same time?
The mantra of global sea level rise is just another tool for those who use it to beat the rest of the species up with.
Only place that sea level is meaningful is at the ocean/land interface.
Long term land movements in some places more than sea level rise.
Down here, Sydney has a very stable site, and the SLR is about 1.1mm/year.. VERY SCARY !
Low tide level is rising faster than high tide level (1.4mm/year vs 0.75mm/year)
No sign of any acceleration, but there is a hint of a small step change around 2000
Apparently, GMSL is as valid a number as Global temperature – not…
“It is unclear why the climate changes at these times”
Large volcanic eruptions.
That is indeed one factor, but only one out of many, many natural phenomena.
Dwarfs everything else. And the ~60 years cycle is gone. Temp increase for 50 years.
The question is,is the acceleration constant, increasing linearly or accelerating?
Look at a pure sinusoidal wave. Start at the most negative point. Capture the wave for 1/8th of a cycle, then project the slope. One can get alarming results if one does not recognize the fundamental waveform.
A lot of climate hysteria is based on that narrow approach. It simply eliminates any and all natural variations.
My take from Figure 3 is that, up until about 1929, sea level was declining. That is a breakpoint beyond which the rise is very linear. If Andy were to calculate the r^2 value for 1929 to today, I would expect that a linear regression would give a higher value than a quadratic. That is, the only reason the second-order fit works well is because of the decline up until 1929.
Why do you think Andy chose C&W 2006 and not C&W 2011?
https://climate-science.press/2022/05/02/more-than-75-of-the-worlds-beaches-stable-or-growing/
I might be missing something, but the “accelerations” shown on figures 3 and 4 seem to be the coefficient for the square term in the polynomial fit. The “acceleration” should be twice the coefficient.
Having said that the use of polynomial curve fitting should be treated with caution. It is easy to do compared with other types of curves but is at the best useful for visualizing the data and smoothing out bumps and dips. For the short time periods used in figures 3 and 4 sinusoidal curves can be fitted, after some difficulty, with very similar Rsquare values. Much more questionable is extrapolating these curves outside the range of the data. In all polynomial curve extrapolation, the highest power term dominates, and predictions become meaningless.
So called “accelerations” are very dependent on the time scales involved. Generally, halve the period and the potential maximum “accelerations” will increase 2, 3 or even 4-fold.
When it comes to longer periods, 100 or 200 years sometimes cycles of behaviour appear due to effects such as decadal oscillations. It can be informative to use higher order polynomials to show trends, but these can have a much greater effect outside the data range and even impinge on values near each end of the data. An alternative is making use of a moving average plot.
Figure 2 shows how small a period the NASA data cover and this is subject to its own problems in interpretation as I have shown in my numerous contributions to WUWT recently. Others have applied quadratic curves over about 30 years and extrapolated for 75 years which is totally unacceptable.
Unfortunately, Man lives his or her three scores and ten, but nature works in centuries, millenniums or longer to weave its climatic changes so we must all be more aware of our predictive limitations.
Hi Alan,
I agree with you on all points. I should have multiplied the coefficient by 2 to get a “true” estimate of the acceleration, but the coefficient itself contained the information I was interested in, which was the relative acceleration of the various sea level rise estimates.
The numbers are so small, relative to the accuracy of the measurements, the absolute value of the computed acceleration is not important. I will add a clarifying note though, thanks for the comment.
“Showing results for how many in a score
twenty
A ‘score’ is a group of twenty (often used in combination with a cardinal number, e.g. fourscore to mean 80), but also often used as an indefinite number (e.g. the newspaper headline “Scores of Typhoon Survivors Flown to Manila”)”
So
“Man lives his or her three scores and ten” = Man lives until age 70
But
“What is the US ranked in longevity?
U.S. life expectancy was 76 years in 2021, according to data from the World Bank, ranking it approximately 60th in the world for life expectancy, behind countries like Estonia and Saudi Arabia.Mar 25, 2024”
What did people do before Google, I guess we must have wandered around waiting for the 6 Oclock network news.
Point taken though – the climate data reminds people who look at it again and again, we have not been watching for long. In about 1000 years we might have a good guess.
Does any nautical chart anywhere have a datum block for sea level rise? They have datum for GPS. So why not sea level rise. BA charts are drawn to 1 foot depth for depths less than 1 fathom.
“sea level is not the same in every ocean basin” It took me a long time to say okay, it seems like water level should equalize but the world is complicated.
“extrapolated to 2100 the sea level rise is only 16 to 33 inches. This is less than the global average daily tide and not a problem for anyone.” Two feet higher would matter a f-lot to some waterfront residents. One must consult “anyone” before one asserts that something would be “not a problem for anyone.”
Kevin ==> The issue that gave you trouble gives everyone trouble — “Well, the seas are water and they will all level out, won’t they?”
No, they won’t, they don’t. For reasons the guy like me (average man in the street with some background in the sciences) hardly understand. But there is no doubt about it…measure at the two ends of the Panama Canal — one in the Pacific and one in the Caribbean. There is a know 20 cm difference — the Pacific being higher. 20 cm is 200 mm.
At the rate of SLR claimed based on the satellite record, the Caribbean will take 60 years to catch up with the Pacific.
What is NOT to worry about is the slow steady 1, 2 or 3 mm a year rise. Anyone not preparing for that needs to go back to grammar school and learn to read and do addition. A “sea wall” made of one course of 8 inch concrete block protects from 200 mm of rise — so those silly folks in Miami, who have succumbed to Miami’s Vice need to get together and raise their sea walls by 8 inches. (Note: That’s a joke…the whole area needs to be pre-declared a disaster zone, see the link).
But you see, the real problems lie in areas that are built already dangerously close to today’s local sea level, often below today’s mean High Water and Mean Higher High Water tidal levels. These areas will always flood at unusually high tides (King Tides, which are perfectly normal and expected) and suffer massive damage from any significant storm surge. Entire cities built on ephemeral sandbars along the US East Coast are insanely at risk.
Predictable sea level rise, either at the carefully physically measured rates seen at Tide Gauges or the speculative rates of satellite measurement, do not pose risks to industrialized nations — adopting and adapting to a rise measured in single-digit millimeters a year runs from trivial to really expensive, depending on how foolishly the city has been built.
The risks are from storms and storm surges to places built far too close to any sea level.
Andy ==> Nice analysis of the issue based on the prominent most current papers.
It is nearly impossible for global sea level to rise by any of the amounts shown in Table One — with the exception of the Church and White 16.5 inches. Even that lowest amount would require an extraordinary geophysical event that is not yet in evidence.
16.5 in / 419 mm in 76 years? That requires 5.5 mm per year, every single year, starting now– almost double the currently measured rate. If we see far less than that for ten years, that rate must increase for the rest of the remaining time.
NONE of the sea level rise “measurements” are dependably accurate as of yet. Until we have a widely distributed network of modern Tide Gauges matched with Continuously Operating GPS units attached to the same structure as the gauge (CGPS@TG), we will not be able to estimate the rise of the surfaces of world’s oceans to any degree of accuracy.
Where we do have CGPS@TG, there is not (as yet anyway) any alarming or dangerous or extraordinary rise in the height of the surface of the sea where it hits the land. What we do see at those reliably measured locations is the same low steady rise seen over the last century or so — a long-term trend of 1-2 mm/yr, with a lot of variation (as you mention, there seems to be some long-wave functions over-writing the linear trend).
Worried about sea level in your own area? Go to NOAA’s Tides and Currents site for your most local tide gauge: Here’s mine. At the bottom left, there may be a link for Sea Level Trends (not all tide gauge stations have this available.) Mine shows that The Battery, on the southern tip of Manhattan Island, is seeing 2.9 mm per year of Relative Local Sea Level Rise. Long-term GPS data show that The Battery, according to the CGPS studies of Snay et al. is subsiding at about 1.35 mm/yr. Yes, that means the the sea surface is really only rising (compared to the center of the Earth) by only about 1.6 mm/yr. You’ll notice that this is in keeping with NOAA’s long-term SLR claim of 1.7-1.8 mm/yr.
For Manhattan — it doesn’t matter is the sea is rising or the land is falling — the result is the same. But the CAUSE is far different.
Thanks Kip
The last IPCC report gives no acknowledgement of sea level rises as it ignores hysterical language used to describe the future of climate in the sort of existential framing, only using one apocalyptic word in describing how the media use inflated language in climate reporting, not ascribing any such connotation to their research.
[[File:Holocene Sea Level.png|Holocene_Sea_Level]]
They are trying to tease out a second derivative signal for a dataset a fraction of the right hand hash marks.
sorry:
https://images.app.goo.gl/HNC18gibRvQWk4EA8
It is and it will start decelerating again very soon, just like in the ~1950s/60s/70s.