9 mm/year of sea level rise in South East Florida? Only if you cherry-pick

Claims are only possible by cherry-picking the multidecadal oscillation with a short time window

Guest essay by Albert Parker

From the “every trick is legitimate to prove the flood will come” department, another example of cherry picking the short time window to misrepresent the natural oscillations of the sea levels. This time the place where global warming is producing three times higher rates of rise is Southeast Florida. In a paper Wdowinskia, Braya, Kirtmana and Wub [1] they claim “the average rate of sea level rise in Southeast Florida increased from 3 ± 2 mm/yr prior to 2006 to 9 ± 4 mm/yr after 2006”.

The alarmism is obviously mounting, as a recent article from NPR demonstrates. [2]

“Miami Beach is one of the nation’s cities most vulnerable to climate change — and its leaders are doing something about it. The city, a national leader in addressing climate, has begun to make improvements aimed at protecting residents from rising sea levels. In South Florida, the rate of sea-level rise has tripled over the last decade, according to a new study from the University of Miami. The rising seas raise questions for many about whether the resort community has a future”.

The 3 ± 2 mm/yr prior to 9 ± 4 mm/yr after 2006 statement is profoundly incorrect for assigning climate-scale trends, based on the use of a very short, cherry-picked time window of only 10 years that magnifies the latest positive phasing of the oscillations along the East Coast of the United States.

Without sufficient data of good quality spanning time windows long enough to clear the trend of the inter-annual, decadal and multi-decadal oscillations, there is no chance to compute a meaningful trend of relative sea level rise by fitting the monthly average mean sea levels (MSL) [3-6]. We proved already in the previous essay that a minimum 60-70 years of continuous data collected without major perturbations to the instrument are needed to infer reliable trends.

That is the case with Miami, as seen in Fig.1, the tide gauge data there stopped in 1981, but for the 50 years it did record, there was no evidence that the trend accelerated except for a brief pulse between 1940 and 1950.


Fig 1 – The mean sea level trend is 2.39 millimeters/year with a 95% confidence interval of +/- 0.43 mm/yr based on monthly mean sea level data from 1931 to 1981 which is equivalent to a change of 0.78 feet in 100 years. [7]

Still, many alarmists continue to cherry pick the few years of data in a time series to prove the sea level are rising at “unprecedented” rates, thus confirming how bad we are burning fossil fuels, main reason why mother nature will punish us with the flood.

This latest claim is easily debunked by analyzing the data where they are measured over a significant time span without major issues in KEY WEST. This tide gauge has 104 recorded years over a time span of 104 years for a completeness of 100%. The first year is 1913, the last year is 2015. Fig.2 shows the MSL, the long term trend computed by using all the data (SLR), and the relative rate of rises based on a short time window of 10 years (SLR10) in different key times.


Fig. 2 – Mean Sea Level in Key West, 1913 to present.


The longer term trend computed by using all the data is +2.36 mm/year.

The SLR10 changes significantly already month-by-month, and dramatically year-by-year or decade-by-decade. Over the years, the SLR10 has fluctuated between +12.93 and -7.05 mm/year.

In 2015 the SLR10 is certainly +11.81 mm/year.

However, in 2009 the SLR10 was +0.54 mm/year.

Going back in time, in 1943 the SLR10 was +0.96 mm/year.

Then, in 1948 the SLR10 was +12.93 mm/year.

Finally, in 1956 the SLR10 was -6.71 mm/year.

It is wrong to claim a SLR of +11.81 mm/year since 2006, and only +2.36 mm/year before, as even larger SLR with 10 years time windows were previously recorded in the past, and then these values were always followed by much smaller values.

Note that in Fig.3, the NOAA plotted trend for the 100 year period is nearly identical to that of the trend in Miami, shown in Fig.1.


Fig. 3 – The mean sea level trend is 2.37 millimeters/year with a 95% confidence interval of +/- 0.15 mm/yr based on monthly mean sea level data from 1913 to 2015 which is equivalent to a change of 0.78 feet in 100 years. [7]

The sea levels are clearly oscillating about the same constant sea level trend and it is therefore more appropriate to say that in Key West the sea levels have been oscillating since 2006 as they did before.


1. S. Wdowinskia, R. Braya, B. P. Kirtmana, Z. Wub (2016), Increasing flooding hazard in coastal communities due to rising sea level: Case study of Miami Beach, Ocean & Coastal Management, 126:1–8.

2. http://www.npr.org/2016/05/10/476071206/as-waters-rise-miami-beach-builds-higher-streets-and-political-willpower

3. A. Parker (2013), Oscillations of sea-level rise along the Atlantic coast of North America north of Cape Hatteras, Natural Hazards 65(1):991-997. DOI: 10.1007/s11069-012-0354-7.

4. A. Parker (2013), SEA-LEVEL TRENDS AT LOCATIONS OF THE UNITED STATES WITH MORE THAN 100 YEARS OF RECORDING, Natural Hazards 65(1):1011-1021. DOI: 10.1007/s11069-012-0400-5.

5. A. Parker, M. Saad Saleem and M. Lawson (2013), Sea-Level Trend Analysis for Coastal Management, Ocean & Coastal Management 73: 63–81. Doi:10.1016/j.ocecoaman.2012.12.005.

6. A. Parker and C.D. Ollier (2016), COASTAL PLANNING SHOULD BE BASED ON PROVEN SEA-LEVEL DATA, Ocean and Coastal Management. Doi: 10.1016/j.ocecoaman.2016.02.005.

7. NOAA Tides and Currents http://tidesandcurrents.noaa.gov/sltrends/sltrends.html


61 thoughts on “9 mm/year of sea level rise in South East Florida? Only if you cherry-pick

  1. ” The 9 ± 4 mm/yr after 2006 and the 9 ± 4 mm/yr after 2006 are statements profoundly incorrect, ”

    Is this a TYPO ???

    [fixed, thanks -mod]

    • Really, so your pause window of 1998 to whenever is not a classic cherry pick?

      [Please follow site policy and use only ONE user-ID, login-ID, and email address. .mod]

      • Nope. The pause window is typically calculated backwards…ie how far back can you go without any warming. Thus, it’s the exact opposite of a “cherry pick”. You would probably be benefited from reading what is actually stated, rather than what you want to believe is stated.

        Also, it’s interesting to note that the calculated pause has included the ’98 temp spike from el niño, and does not start with it. So, the complaint that the pause starts from the highest point (and thus everything will of course be lower) is not only false, but is utterly backwards from the truth.


      • ripshin,

        …is not only false, but is utterly backwards from the truth.

        That is my experience with pretty much all statements from the mouths of liberals, environmentalists and climate scare mongers. For something close to the truth, just flip a liberal statement on it’s head and you’ll be pretty close.

        Liberals can’t convince people of their theories using facts and observations. It must always be scare tactics, playing on emotion and use of hyperbole dressed up as truth. That’s why large coercive government MUST be at the heart of any socialist system.


  2. below the first quote box, cut & paste error with “The 9 ± 4 mm/yr after 2006 and the 9 ± 4 mm/yr after 2006 are statements profoundly incorrect…”

    please moderate out this comment but do fix the typo…

    [fixed thanks to previous commenter -mod]

  3. Even @ 9mm / year that’s only about 3.5 inches per century. Who cares? Although I agree with Miami’s approach at infrastructure improvement (adaptation) rather than trying to stop climate change (mitigation). Adaptation measures are beneficial whether or not CC is anthropogenic and “dangerous”. Protecting from SLR would also increase protection from hurricanes for example.

    • Indeed; mitigation over adaptation seems stupid to me. We have clear historical evidence that
      adaptation will be required regardless of whether we’re altering the climate to a sufficient
      degree – or not.

      • I am confident that my progeny will be intelligent and resourceful enough to adapt to whatever climatic paradigm they experience, if they are not indoctrinated with pseudoscience and guilt from childhood.
        The urgent detour of “fighting climate change” is presented as a sole option because it’s the only way they can sell governmental subsidies of the failing, energy-sparse wind and solar industries. Furthermore, the political climate change the UN has planned can be more quickly accomplished by stressing mitigation now (by emergency executive order) and adaptation later on becomes a reason to “tighten the thumbscrews” on the masses.

    • The city, a national leader in addressing climate, has begun to make improvements aimed at protecting residents from rising sea levels.

      And, as they finally figure out they need to adapt to changing climate (it’s mostly natural, that’s what it does, duh!), I wonder how many citizens are wishing they hadn’t wasted so much money and time on attempts at “climate control”.

  4. Can you present the opposite side of the oscillation? If total water is the same, and it rises here, it should fall there. How about trying to slip a story about SLF into the papers with a title like “Is global warming drying up the (some ocean)? Scientists extrapolate desert sand bars off the coast of (some land).”

    • Cannot be done because the change (the slosh, so to speak) does not have to be along some other coastline. It could be out in the middle of the Pacific. One reason Sat alt gets a different answer that tide gauges. The closure problem also suggests the sat alt SLR estimates are systemically biased high by about 1/3–3.2 should be ~2.2.

      • There is a reason they call it “sea level”.

        Water, being a low viscosity fluid, can flow freely from “high” places to “low” places, and seek its own level.

        So you cannot have a different rate of change for sea level from one place to another.

        If sea level increased more at one place than some other place, pretty soon people would begin to notice this pile of water sitting there with no visible means of support.

        So I don’t buy their alleged different rates of sea level rise from place to place.


        Now land is not low viscosity like water so land might be able to pile up in one place more than another.

      • ‘Water, being a low viscosity fluid, can flow freely from “high” places to “low” places, and seek its own level.’
        But what level? What you are overlooking is that the ocean has non-uniform density. A column of light fluid adjacent to a heavier one will rise due to buoyancy, with a higher level surface. Then there will be a pressure gradient tending to push the light toward the (lower) heavy near the top, and the other way at depth. That will tend to mix and equilibrate, but the time scale is very long. And we know the density differences persist.

      • GE Smith

        I agree that on a perfectly spherical planet of uniform non-freezing temperature without land features or undersea bumps or rotation or a sun or a moon or wind or living creatures, there is a remote possibility that water would settle equal depth.

        You’re not slicing spherical cows again, are you?

      • Persistent winds which create currents can pile the water a little in one area and lower it in others. When we are talking mm/yr, it is not hard for this to create differences in rise or fall from place to place. In addition, extra rainfall in a basin compared to another (e.g., Indian Ocean) will change the relative sea level a little and it will take time for water movement to equilibrate the levels. Density changes due to rainfall and river input will also have an effect as Ristvan noted.

  5. “9 ± 4 mm/yr after 2006”

    This seems to claim too much accuracy.

    NOAA published a US SLR report in 2009 that included estimating the 95% confidence intervals of SLR for tide station data as a function of record length. The result was (equation 8, page 59):

    y = 395.5 / (x^1.643)

    where y is the 95% confidence interval, as in R mm/yr +/- y mm/yr;
    x is the record length used in years.

    For a record length of 2006 – 2015, or x=10 years, this gives y=9 mm/yr.

    The paper should be reporting the sea level rise since 2006 as 9 mm/yr, +/- 9 mm/yr.

    • Wow, so using accurate error bars, sea level rise could be as high as 18 mm/yr since 2006. It is worse than we thought.

      • Dan-

        Indeed. It can be as much worser as you want.

        Taking satellite sea level data off Miami’s shore, the year 2015 shows a SLR of 46 mm/yr, +/- ???.

        Key West tide gauge SLR for 2015 (1 year) is 100 mm/yr, +/- 395.5 mm/yr.
        So Key West may currently have SLR of 495 mm per year.
        Or Key West may currently have SLR of -295 mm per year.

      • 495 mm/yr? In a little over a century, there is a chance the water will be at my door in Ohio. Good thing they are building an ark just across the border in Kentucky.

      • Dan-
        ” In a little over a century, there is a chance the water will be at my door in Ohio. ”


  6. How does one discriminate terrestrial elevation changes, a local manifestation, from seal level changes, a global artifact?

    Islands sink and rise, the Himilayahs are rising so something is falling.

    • Used to be very difficult, in the Japanese sense. But with the advent of differential GPS, is is now very easy. Unfortunately, as of 2009 (source is a Masters thesis at USF comcerning reducing satellite SLR uncertainty) there are only ~70 long record (>50 years) tide gauges with such a GPS determined land motion estimate within 100 km.

    • Great question. Short answer:

      One can look for “stable platforms” like Australia or the Bahams that are thought not to be bouncing around and use their data only.


      One can correct (possibly) known effects like glacial isostacy. then hope that if you throw all the measurements in a blender and average them, you will come up with the one true value.


      One can use satellites and hope that if you take millions of measurements and average them, the fact that you only know the satellite’s position to a few cm won’t prevent your achieving sub mm accuracy.


      You can just make something up and publish it.

    • This new metric of ‘seal level changes’ intrigues me. Increasing seal level means less fish which would cause the sea level to decrease.

  7. Ya know, I lived in New Jersey into the 1970s. We used to vacation at Long Beach Island in the 50s and 60s. One thing that impressed me profoundly after seeing that veritable sand bar barrier island cut into pieces by the hurricanes of the 1960s is that only dumb people build at low sea level near the ocean. I do not care what the sea level is. Yeah, it was really nice back then, but if you built you built on 20′ high piles and prayed a lot.

    • only dumb people build at low sea level near the ocean…

      sea ports are really hard to build in Minnesota

      • Some very shrewd people build and develop high-priced real-estate on the shore, maybe even a barrier island, maybe the (New) Jersey shore, but only if they can offload the insurance risk and cost to taxpayers. Like the former mayor of NYC whose day job included real-estate development.

  8. Subsidence.

    “What people build, particularly on land with looser soils, could worsen the blow by sinking some coastal areas faster than nature would alone.

    One project designed to quantify this effect focused on the Fraser River delta in western Canada, home to the coastal city of Vancouver. Using radar measurements taken by satellites, geophysicist Stéphane Mazzotti and colleagues found land subsidence, or sinking, that appears attributable primarily to the weight of what was constructed atop it.

    “Subsidence due to human activity exceeds the natural rate in heavily built areas,” says Mazzotti, whose findings were published in Geology.

    Vancouver itself, built on solid substratum, is not at risk. And in undeveloped or lightly developed portions of the metropolitan area, natural consolidation of upper Holocene sediments is causing subsidence of only 1 to 2 millimeters per year. But in heavily built-up locations outside the city—including the Vancouver International Airport, ferry terminals and industrialized zones—the drop was significantly greater: 3 to 8 millimeters per year.”


    • Much of Florida is composed of coquina (broken sea shell) which is porous and subject to dissolution by acidic groundwater. Every once in a while, a spectacular sink-hole opens up to emphasize this point.

  9. Funny how sea rise can be different in some places. Nonexistent in some places and surging in Miami?
    I’m just a simple man, but when I fill my bath tub the water rises the same everywhere.

    Well I never take baths so I’m going on memory and presumption.
    Is it possible that my tub could run over the rim on one end while remaining below it on the other?

    I live in Oregon, obviously.

    I go to the beach, occasionally, even though many people have stopped going due to fear of the big one.
    Worry worry worry.

    I have yet to see anything different at any beach. The tide predictably swings twice a day and by golly sometimes a little and at times a lot. We are told in advance.

    Yet many Oregon alarmists swear there are big changes underway.

    How is it that I am supposed to stand on a beach I stood on 50 years ago and see the exact same thing and be worried about sea rise? I can’t.

    There are countless studies and reports like this which try try try to get be spun up.

    IMO they are all worse than useless as they devour vast sums of resources while producing nothing of use.
    They just sit there where ever they are stored.
    They are piling up while the heap provides no value for anything but to compel a bigger pile.

  10. South Florida is horrible for media coverage of sea level rise. Every year when the astronomical high tides occur, and some minor street flooding occurs as a result, our local NPR stations go bat-sh*t crazy on rising sea levels. The Democratic politicians and even some Republicans will trot out the tired canard that CAGW will soon render Miami Beach uninhabitable. If we measured whether or not Miami Beach is uninhabitable by looking at real estate values along the beach rather than tide gauges, things would be looking good. And a big part of the problem (other than big storms and normal barrier island movement due to the Gulf Stream and wave action), is that because people who live near the water want to SEE the ocean, and they tend to flatten out the beach dunes, rip out the mangrove bushes, and drain brackish estuaries for easier access and more comfortable, mosquito-controlled lives. None of this is to say that periodic street flooding by salt water isn’t a major pain in the ass for people and their cars, not to mention infrastructure such as bridges, utility cables, water pipes and more. But such maintenance headaches are just part of the normal costs of living along a low-lying beach where millions of people want to live and vacation.

  11. So 3+/-2 and 9+/-4 are the measurements of concern. The former being the earlier, less worrying measurement, the latter being earth is doomed measurement.

    When last I did math 3+2=5
    Similarly 9-4=5

    I’m old and haven’t done the new math but IIRC 5=5. Wouldn’t that automatically render the result obtained, regardless of how the numbers were fudged in the first place, statistically insignificant? Yes, I fully understand I’m only looking at one in a range of outcomes, but if I threw error bars on their numbers of 3 mm and 9 mm the result would show it plainly anyway.

  12. please help me out with this… if the sea level is to change, will it not increase the same measurement throughout all the seas? recent article referencing 5 Islands in South Pacific are now under the sea.
    No Id as to what 5 Islands. Or is this the land that China is using to build their new Island bases?

  13. “This tide gauge has 104 recorded years over a time span of 104 years for a completeness of 100%. The first year is 1913, the last year is 2015. ”

    1913 through 2015 (inclusive) is 103 years, not 104 years.

  14. Sea Level Acceleration/Decelaration Review
    A review of trend models applied to sea level data with reference to the ‘‘acceleration-deceleration debate’’ Hans Visser,S€onke Dangendorf, and Arthur C. Petersen 2015

    Here we shed light on the controversial discussion from a methodological point of view. To do so, we provide a comprehensive review of trend methods used in the community so far. This resulted in an overview of 30 methods, each having its individual mathematical formulation, flexibilities, and characteristics. We illustrate that varying trend approaches may lead to contradictory acceleration-deceleration inferences. As for statistics-oriented trend methods, we argue that checks on model assumptions and model selection techniques yield a way out. However, since these selection methods all have implicit assumptions, we show that good modeling practices are of importance too. We conclude at this point that (i) several differently characterized methods should be applied and discussed simultaneously, (ii) uncertainties should be taken into account to prevent biased or wrong conclusions, and (iii) removing internally generated climate variability by incorporating atmospheric or oceanographic information helps to uncover externally forced climate change signals.

  15. “Without sufficient data of good quality spanning time windows long enough to clear the trend of the inter-annual, decadal and multi-decadal oscillations, there is no chance to compute a meaningful trend of relative sea level rise”.
    These long-term variations are well known to all. To attempt to draw any conclusions from an ‘analysis’ that does not try to account for them is beyond disingenuous, and very close to outright fraud.

  16. Another “success” for “Pal” review.
    That c*** like this gets published is clear evidence of the corruption in climate “science”.

  17. As a green pro-wildlife environmentalist, Florida’s sea level rise is great news!

    More alligators and crocodiles, more turtles, more great white and blue herons, more ducks and geese, more fish. It’s all good.

    • Would be nice to see the FL Disney facilities preserved under several fathoms of seawater.

  18. Wow – these people are either utterly insane, utterly stupid or utterly corrupt.
    Why do they not just look at a graph of the overall data run, and see why their short term cherry-picked trend indicates nothing.
    This is a brilliant example of foolishness or intentional deception perpetrated using statistical trickery.
    When I fist encountered the coastal gauge data, I saw immediately that all the acceleration claims were busted by the evidence. All the graphs show a generally linear trend (with only a tiny number of exceptions where presumably the gauge has subsided due to development – such as Manila.)
    How long can this theater of nonsense continue?
    Meanwhile in the real world, China has shown that it has no interest in this SLR acceleration nonsense and is planning for the long-term future by building brand new islands, complete with vast airbases and harbours. The Chinese are not stupid. We are worried about losing. But they are only planning to win.

  19. Wife and I were down in Key West in October. Had a high tide and Duval Street started to get flooded. Lucky for us the bars stayed open despite the sea level rise. We high tailed it back to New Orleans to hide behind the levees.

    • That explains the rock-bottom real estate prices in Key West. :-)

      406 United St, Key West, FL 33040, 4 beds 5 baths 3,624 sqft, $2.59M

      715 Duval St # 2, Key West, FL 33040, 3 beds 3 baths 2,387 sqft, $1.7M

      (The Lowe Mansion) 620 Southard St, Key West, FL 33040, 5 beds 6 baths 10,822 sqft, $8.4M

  20. At 9 mm/year, Miami will be at zero elevation MSL in…199 years. At 2.37 mm/year, it will take 762 years. The approaching calamity reminds me a lot of the steamroller scene in “Austin Powers: International Man of Mystery.” Austin and Miss Kensington are escaping Dr. Evil’s lair on a steamroller, moving at about 1 foot per second, and see that an Evil henchman is in the way — 30 feet away. They shout at him to get out of the way, and he shouts at them to stop, but stands frozen in terror until they finally run over him (and then stop). Does anyone think that 199 to 762 years is too short a time for Miami to “get out of the way?”

    The Miami skyline will continue to change, over the next two centuries, and I can’t believe that no action will be taken to bring in more dirt to raise the elevation. It would be more effective than standing still and shouting “STOP!” at civilization.

    • Boston managed to add over 1000 acres between 1630 and 1900 using shovels and horses, as sea level rose around 1.7 mm/year. I think future Miami can cope, and apparently the beachfront property owners think so too. For example:

      9814 W Broadview Dr, Bay Harbor Islands, FL 33154, 6 beds 5.5 baths 6,722 sqft, $7.95M

  21. Bully for sinking Key West because this is what Oz CSIRO reckons globally-

    “We have used a combination of historical tide-gauge data and satellite-altimeter data to estimate global averaged sea level change from 1880 to 2014. During this period, global-averaged sea level rose about 23 cm, with an average rate of rise of about 1.6 mm/yr over the 20th Century.”


    In Oz we have some very old rocks like Hallet Cove where you can read the signs-

    “The level shore platform has been eroded by wave action across the rocky coastline during the past 7000 years. The big fold was formed during the mountain building about 500 million years ago. During the Recent ice age about 20 000 years ago, sea level was about 130 metres lower than today and South Australia’s coastline was about 150 kilometres south of where Victor Harbor now is. The ice cap started to melt about 15 000 years ago. Sea level began to rise and reached its present level about 6000–7000 years ago.”

    Yes that could be an average rise of 16.25mm/yr for 8000 years and it’s not hard to see why geologists like Ian Plimer are shaking their heads in disbelief at the antics of todays doomsayers.


  22. Sea level in the geological sense is referred to as either eustatic (global, volume change) or relative (change in local/regional shoreline due changes in sedimentation rates, uplift, subsidence). Without specifically stating what type of sea level change Miami may or may not be experiencing leaves a door open as to the probable cause(s) of Miami’s problems with water along the coast there. However it seems clear their intent was to blame melting ice and perceived global temperature rise as the culprit.

  23. The frame of reference is complicated. Bench marks ( tidal ) fluctuate. The materials for example in and around Miami Beach that support the existing infrastructure are unconsolidated granular deposits and fill over bay mud and coquina. Since the placement of buildings to cover as much of the expensive real estate along the waterfront has occured over the last 60 years it would be surprising if no vertical movement in the shallow supported benches has not occurred.
    As example, there is data from instrumented test caissons that were used to construct the WTC that indicated the deeper limerock/sandstone strata were compressible. Punch past the 80 ft or so depth to the foundation material and one could run an H pile a long way. This building loading is one aspect of a source for error downtown.

    A second source of recompression in the upper materials is the fluctation in total load caused by ground water withdrawal of the water from the Miami Aquifer.

    Correlation of the old USGS datum with the newer NGVD and satellite are other sources.

    It would be interesting to see how these studies and the references have treated the bench mark data.

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