A geological perspective on sea level and storm surges.

Guest post by David Middleton

“Sea level has already risen by about a foot, 1 foot, in much of the Southeast, which means Matthew’s storm surge was higher, and the flooding was more severe.”

–Hillary Clinton, Miami FL, 11 October 2016

When I read this quote in William Anderson’s recent post, I was reminded of Joe Bastardi’s appearance on the Sean Hannity Show on the eve of Hurricane Mathew’s landfall.  When asked about the assertions that sea level rise has made hurricane storm surges more destructive, Mr. Bastardi said that it was insignificant.  The influence of tides and waves were far more relevant than a minor rise in sea level.

To illustrate the irrelevance of sea level rise, I devised a little topographic exercise using NOAA tides & sea level trends and a USGS topographic map of the Jacksonville FL quadrangle.  There are two NOAA sea level stations in this quadrangle: Fernandina Beach and Mayport.  I chose Fernandina Beach because the record goes back to 1897, Mayport only goes back to 1930.


Sea level trend for Fernandina Beach, Florida (NOAA)


Tidal range for Fernandina Beach, Florida (NOAA)


1994 USGS topographic map of Fernandina Beach, FL area (USGS).  Contour interval = 1.5 meters.

To evaluate the significance of 2 mm/yr of sea level rise since 1897, I constructed a topographic profile (A-A’) along Atlantic Avenue from Nassau General Hospital (A) to the shoreline (A’).


Topographic Profile A-A’ –  Vertical Exaggeration ~ 40x.


My next step was to plot the sea level data at the same vertical scale as the topographic profile.


Can you see the sea level curve? It’s the squiggly green line, straddling the o m elevation line.

What effect has all of this sea level rise had on a 10′ storm surge?  Just above zero-point-zero.


Note that the height of a 10′ storm surge hasn’t changed much since 1897; nor will it change very much by 2140 at 2 mm/yr.

My next exercise was to compare the typical tidal range to sea level rise.


Anything imperiled by 1′ of sea level rise is already flooded at high tide.


Recommended Reading

Oh say can you see modern sea level rise from a geological perspective?

Featured Image Borrowed From



103 thoughts on “A geological perspective on sea level and storm surges.

    • First semester, freshman year (1976), Earth Science 201, Physical Geology… I always knew that class would come in handy!
      Thanks Anthony!

  1. Maybe this betrays my Alberta ignorance, but is sea level the low tide mark, high tide mark, or some sort of average? The last figure suggests that sea level is the low tide mark.

  2. Nothing better than a geological perspective on sea level. Out side the profession, I don’t think many realize how much we study sea level & how important it is in interpreting the sedimentary / geological record.

    • If not for lots of climate change and sea level variation, sedimentary geology wouldn’t be much fun.

    • Could one of you geologists explain why we never read or hear any geologists speaking out on this kind of AGW FUD?

      • Speak out where? The AAPG has been disengaged on the subject since 2006. The Houston Geological Society will occasionally feature climate change talks… I’ve been thinking about putting one together and submitting it. Dr. Neil Frank gave a great presentation at a Ryder Scott Reserves Conference (his presentation included several slides from WUWT, including one of mine). We speak out… But we are largely shut out of the AGU, AAAS, Nature and most other venues. Just look at the hurdles thrown up in front of Roy Spencer & John Christy.
        On a side note, I attended the Society of Exploration Geophysicists (SEG) conference in Dallas on Monday. The AGU had a booth… I never saw anyone visit them… 😉

      • as a side note–just received the yearly “news letter” from the geology dept I graduated from back in the “stone age” The dept has grown tremendously since my time there, and the news letter is now a full blown magazine featuring reports from all the faculty and staff on what they have been up to. Haven’t quite finished reading yet, and with all sorts of interesting studies going on (even some in paleoclimate), not one mention of agw, let alone cagw, and only one mention of CO2–in reference to a new piece of lab equipment that can read the amounts of CO2 in a rock , (or sediment sample) along with the amount of H2O, and other constituents. From the looks of things, a visit there would be like a visit to another planet compared to the Geo Department of my day.

      • Ian Plimer, mining geologist and professor out of Australia, wrote Heaven and Earth a few years back (2012?), with material that is easily understood and provides a good update on paleoclimate from a geologist point of view….with more than 2,200 references….

      • Plimer’s book is very good. Pat Michaels’ books are probably the best combination of climate science and readability.

      • Not a geologist. But I’ve been employed by a couple of very large companies in the industry for many years and have come to know quite a few geologists and geophysicists during that time. They all tend to pretty much poo-poo the whole idea of AGW. But mostly, they have other stuff to do, as ristvan noted.

      • I thought about doing another profile with a 20′ wave height… But I figured that would be overkill.

      • during Mathew, here in Savannah, the report of a “storm surge” of nine to eleven feet meant a high tide of nine to eleven feet.

    • The storm winds would build the same amount of ocean surge regardless of the sea level, right? Of course the storm surge can augment the height of the water, and it will add this augmentation to whatever the current tide is, but the amount of augmentation itself would not increase. Consider a storm out in the open ocean, the capacity for wind to move water does not change with a change of water height.

      • Wave action near shore is a function of the profile of the bottom to a significant degree and thus considerably variable from place to place.

      • Pictured above are the NOAA Predicted and Measured Tidal Gauges for The Battery, NY and Kings Point, NY. It shows the Spring Tide expected without Sandy (blue), the measured tide with storm surge (red) and the difference as the storm-surge without tidal effects (green)

      • If I find the time next week, I’ll see if I can post this and The Battery sea level data on a topographic profile.

  3. The destruciveness is primarily a function of man’s stupidy and greed in building in places prone to flooding due to storm surges, tides, and waves.

    • You got that right, the more money folks sink into making the coastline habitable, the greater the cost of any level of tropical storm. The illusion is that the storm was “worse” because it had a higher remediatiory cost.

  4. This is not such thing as perspective in win-the-day courtroom tactics. Just ask any lawyer, like Hillary

  5. It’s been a long time since I had to calculate vertical exaggerations (actually, i didn’t have to, I did it for fun), but if I did it correctly your VE is approximately 55x, and the sea level rise is still indistinguishable from 0.

  6. Hillary means carbon tax but that word is banned during the campaign and its rehabilitation depends on down ticket voting for the Senate.

  7. I feel like I ma missing something here. 2mm per year = .08 inches per year.
    119 years x .08 inches = 9.52 inches
    I convert to inches because I’m more familiar with how big an inch is…
    Those charts with the green line indicating sea level rise since 1897 seem REALLY wrong. There HAS been almost a foot or 1/3 of a meter rise since 1897.
    I don’t think it’s anything to worry about, but those charts simply look wrong to me.

  8. Very nice post and illustrations.
    FWIW, there are about 85 high quality long record tide gauges like this one around the world. About 40 of them have differential GPS land motion sensed within 10 km of the gauge. Unfortunately NH biased, but that should not matter much given that water seeks its own level. The result from these after diff GPS correction is ~2.2mm/year, and no acceleration since about 1900. So your nice example is quite representative of the entire globe.
    Importantly, these tide gauges also show no acceleration in SLR, just like your example, unlike CAGW theory and Jim Hansen’s latest nonsense. And, the ~2.2mm/yr value closes nicely with SLR ~= thermosteric rise plus ice sheet mass loss. The Argo estimate for the former is 0.6mm/yr, the GRACE estimate for the latter is 1.6mm/yr. See Chen et. al. Nature Geoscience 6: 549-552 (2013) and then apply the 2013 diff GPS GIA correction to the earlier GRACE Antarctica estimate, subtracting 0.2mm since Antarctic ice loss was overestimated by the faulty modeled GIA used in all papers before YE2013. That detail was covered by McIntyre in a post some months ago. 1Gt of ice is ~1 km^3 =>2.78 microns of SLR for those wanting to do the calculations themselves. Calculated in essay PseudoPrecision in ebook Blowing Smoke.
    Lack of closure shows that the newer satellite altimetry estimates of SLR are significantly biased high. Warmunists create artificially accelerating SLR graphs by sticking satellite including a GIA guess onto tide gauge starting 1993, pretending apples to oranges doesn’t matter while not disclosing the closure problem. Diff GPS corrected tide gauge is the highest quality SLR data we have. Not the sat alt SLR stuff. Reading the Jason 2 accuracy and precision specs, plus understanding the impact of waves on the radar altimetry signal, explains why.

  9. The one thing missing is the topographic change since 1897. In a natural setting, 2 mm of sediment is easily deposited for every 2 mm of local sea level rise, and the coastline position does not change and there is no apparent sea level change. Local changes in sedimentation or subsidence/uplift overwhelm the very little increase in ocean volume over the past several hundred years (several thousand really), ergo, there technically is no ‘global’ change in sea level.

  10. I agree 100% with this. I don’t understand why the press or presidential candidates wail about rising sea levels when they don’t understand the net impact. Once again, there are dozens of articles about chronic flooding in South Florida from “King Tides” due to climate change.
    Except there has always been King Tides (or Spring Tides) in South Florida, and such flooding has always occurred.
    Just the other day, there was an article on Climate Central which claimed that 76% of all coastal flooding is due to man-made climate change. Such a conclusion seems like such a senseless exaggeration — without any supporting documentation. Ironically, they mentioned Fernandina Beach, FL.
    “In some locations, the influence from our carbon pollution is particularly dramatic: in 11 places, ranging from the Miami area, to Wilmington, N.C., to Seattle, more than 80 percent of flood days in a 10-year span can be attributed to human-caused sea level rise. And in both Honolulu and Fernandina Beach, Fla., all of the flood days (138 days and 16 days, respectively) between 2005-2014 were made possible by climate change.”

    • Of course. If there has been one millimeter of sea-level rise due to climate change, of course the top millimeter of every flood from then on was only possible due to carbon pollution /sarc.

    • So “building on a flood plain” is now “human-caused sea level rise” and caused by “carbon pollution”?
      “[A]ll flood days … made possible by climate change.” Does that mean that if there was no “climate change”, it would be impossible for flooding to occur? If only Noah’s contemporaries had stopped burning all that coal and natural gas.

    • The quote includes Seattle.
      The region just had a rainy day. Baring (40 miles ENE of Seattle had 3.35 inches).
      Flooding in the region increased over the last X number of years because of urban developments (roads, parking lots, housing, and other hard surfaces), and increasingly sediment clogged streams. The region is mostly built on deposits left after the Fraser Glaciation and the Puget Lobe ice.
      Development causes runoff to come faster and the peak to be higher — look for studies of the “urban hydrograph.”
      The State of Washington has “The Washington Carbon Emission Tax and Sales Tax Reduction”, also known as Initiative 732, on the November 8, ballot. Some do not want it because it does not direct money to “green” actions. In any case, it is a distraction from serious problems.

      • When I lived in Seattle, they used to have an “underground tour” of the area that built when the first floor would flood twice a day at high tide and the toilets would back up. When the city burnt down, much of it was built higher and you can still find buildings which have an unoccupied lower level.
        I don’t know if they still have that tour, but it was one of the best things to do in Seattle.

  11. “Sea level has already risen by about a foot, 1 foot, in much of the Southeast”
    Sure it has, but since when? The southeastern US from Cape Cod south has been slowly subsiding ever since the ice age and will go on doing it for many thousand years more (unless there is another Ice Age).

    • In a lot of places vertical land motion (up and down) is much greater than along the US SE coast, thanks to both isostatic rebound and plate tectonics. That is why a simple average of many hundreds of tide gauges isn’t very accurate even if thought to be relatively ‘still’. With diff GPS land motion correction the smaller subset is quite precise.

      • The Southeastern US is sinking mostly due to isostatic rebound since it is in the “forebulge zone” of the Laurentide glaciation. Down in the Gulf subsidence due to sediment load from the Mississippi also cuts in.
        And it is very rare for any area to be completely “still”. Long-term GPS measurements help, but even that is shaky at the millimeter-per-year level since the GPS coordinate system isn’t really that precise. NASA has been trying for years to get money for more precise geodetic satellites but nobody seems interested.

      • “isostatic rebound and plate tectonics”…agree. However, for non-geologists these terms cause eyes to roll back in the head and any attempt to explain these geologic processes (or any other geologic process) loses the audience.

  12. You could make the same comparision to daily and yearly temperature variations and the threat of Global Warming, it would hardly be visible.
    Half the year (or day) we would fry, and the other half we would freeze to death. Amazingly we are still around to notice the nature and the climateers doom predictions.
    Sea level seems to be the least influenced by CO2 or temperature. Some of the series rise a bit more than others, but no one seems to follow temperature or CO2. But never let a good story die because of facts.

  13. Sea levels are also greatly affected by whether a particular part of the coast is rising or falling often due to isostatic rebound (glacial) although other circumstances also affect land changes.
    Sea level rise is one of those things that probably shouldn’t be averaged, as it varies enormously from place to place and ocean basin to ocean basin. For example, engineers would consider the local circumstances when considering flood defences, as in the US we have places where Sea level is rising 10mm a year and in other places falling by 17mm a year so taking the global average of 3mm a year would be pointless in both circumstances
    Sea levels in roman times were generally probably higher than today excluding any land changes

    • Tony, that is why tide gauges are locally very useful for planning and adaptation.
      But the CAGW meme is that whatever SLR is locally, it will accelerate from melting ice sheets and warming oceans and soon drown coastal cities like Miami and Bangkok. That is why knowing what the true global rate is, and whether it is accelerating, is so important. Clinton was just wrong last week about Matthew. In two ways. Obama was wrong about Miami Beach in 2009. Hanson and Rahmstorff and their peer reviewed papers are all just wrong also, making absurd assumptions about tipping points (see essay of same name in my ebook). And MSM doesn’t fact check, just passes the political nonsense on as if scientifically true. Dave Middleton has done a superb job here of calling out Clinton and Obama using a little real geology science. Regards to you and your historical research.

    • One of the problems, is that there are very few genuine sea level reconstructions spanning the Holocene, apart from a couple of spectrally FUBAR hockey sticks.

      • David there are though, a few medieval castles and even older ancient cities with harbors and docks that are a quite a ways from the present shoreline. That should be enough to say that it is likely sea levels were higher in the past so therefore the present level and rate of rise is not a threat. That is only common sense… which sadly seems to be lacking in the alarmist crowd.

      • In the book “Water World” there are shown many ancient cities that are under as much as 60 feet of water.

    • “Sea level rise is one of those things that probably shouldn’t be averaged, as it varies enormously from place to place and ocean basin to ocean basin. ”
      too funny.
      in the US we have an inflation rate. it varies from place to place. therefore there should be no CPI
      Height, income, racial mix, unemployment, crime… all vary from place to place.
      If things DIDNT VAR we would not have to average.
      We average BECAUSE they vary and then by averaging we can examine WHY they vary according to
      There is for example an average number of deaths from guns across the US.
      by AVERAGING we can see that places like chicago have higher rates… and we could offer up the
      observation that their tough gun laws do nothing to effect the murder rate.
      so.. its BECAUSE THINGS VARY that we average.
      of course you cannot average anecdotes or diaries

      • The coast of Washington State dropped ~10 feet in January of 1700. It will do something similar again.
        There is good reason for planning for the anomalies.

      • Any average should be reported with the range of uncertainty attached directly behind. Reporting an average of 2mm per year without saying ±2.5 (Sigma 1) or whatever the figure is, misleads. All measurements, all of them, have an uncertainty which should be recorded and propagated through any subsequent calculations. There are standard ways of dealing with such calculations. The more complex the calculation, the greater the uncertainty because they compound. SLR is not measured to a 1000 microns so I don’t want to read numbers that include a long string of digits. That’s false precision.
        The uncertainty applies only to the data sets used. It is not permissible to estimate the uncertainty about sites not measured because there is no instrument involved. Thus the statement of sea level rise has to be qualified with words such as, “This figure is calculated from the available data sets which are sparse in many areas of the planet.” This was done in the article above. Congrats.
        Now, what is the SD of the SLR provided, and how many years must pass before the level in any selected year is exceeded beyond Sigma 2? The calculated average value may have increased, but the difference may not be statistically significant.
        I loved the reference to 1 GT of melted ice = 2.78 µm of SLR.

      • Except you can’t average intensive properties (well, you can but the averages are meaningless) Mosher seems to ignore that physical fact.

  14. Given that 11″ of this foot was already experienced before the average building was built then even if Crimton attributes 100% of the sea level rise to AGW that means a 30′ storm surge would have been a mere 29’11” had our grandparents adopted a more carbon neutral lifestyle. I doubt even the residents of the street worst hit would have accepted that tradeoff if given a time machine.

    • The Marshalls are very tectonically active. Strides the boundary of Pacific and Australian plates. That is why the new (2007) tide gauge at Majuro has diff GPS correction. Any tide gauge in the Marshalls without diff GPS correction is not measuring sea level change only. Check your analysis against Majuro. See also Nils-Axel Moerner’s guest post here on this in 2013. He is arguably the world’s top expert.

    • Sea level in the Western Pacific drops during El Niño cycles… Assuming a La Niña forms, sea level will rise in the Western Pacific.
      It’s “funny” how sea level in the heart of climate refugee-land often moves in the opposite direction as the rest of the world

  15. I always LOVE a good geologic perspective. Thanks, David. Here in South Florida, we’re just finishing up 4 or 5 days of King Tides, with local salt (brackish) water street flooding. Monday was the worst, with water covering some nearby streets to a depth of about 5 inches for about an hour centered at the time of high tide. It’s been a little worse than last year, due to steady NE onshore winds, which pile up water along the whole coast. I don’t know if any of that water can be attributed to Matthew, but I suspect not much, as the storm surge was minor during the closest approach here. For those who don’t know, the northward flowing Gulf Stream gets very treacherous during North and NE winds. The winds push against flow of the water at the surface, raising waves that are higher than the wind speed would normally create. In the Gulf Stream, even in very deep water, N and NE winds can raise large waves, white caps and breaking surf. Some of that water probably is creating something of a surge now, during the tides.
    In a nearby commercial area, there’s a block of businesses that routinely sandbags their street frontage for King Tides, and the worst of it is when thoughtless drivers speed through the standing water on Las Olas Blvd. making a wake that increases the height of water the business owners need to deal with. Of course, NPR and local news media (whom I praised during their continuous coverage of Hurricane Matthew) are going crazy with claims of how this annual event is getting worse and worse, and it’s time to DO something… blah blah blah. Next month’s full moon will also have fairly high King tides, but then things should go back to “normal.” The moon is/was approximately 220-225K miles from Earth during these tides.
    I had posted a few comments here on WUWT during Matthew, and in one of those conversations I mentioned that power in my area is supplied by underground cables and transformers. Well, last night, power went out at my place and on the whole north end of my street for several hours. This was PROBABLY (I don’t know this for sure) due to a salt water incursion into the underground transformer vault. The FPL guys were stellar and had power restored quickly. Some of the local grass lawns are dying back due to salt water incursions, too. This grass will bounce right back and green up after King Tides end, and some fresh rain falls. To me, these inconveniences are just part of the everyday costs of living in a sub-tropical coastal area. I feel very fortunate that my area was spared the wrath of Matthew, unlike St. Augustine, Jacksonville, the Carolinas, and Haiti and the Bahamas.

    • Outstanding, Mickey! Sea levels are (and have been) rising relentlessly.
      Plan for it, you unaccountable bureaucrats and politicians. But, you always just blame climate change for your failures. “Nothing we could have done about it, but just give us more money/power and we will fix it.”

  16. “Sea level has already risen by about a foot, 1 foot, in much of the Southeast, which means Matthew’s storm surge was higher, and the flooding was more severe.”
    –Hillary Clinton, Miami FL, 11 October 2016

    Huh? I thought sea level rise was supposed to a GLOBAL threat.
    But I’m sure The Clinton Foundation will buy stilts for all those poor people on Tuvalu.
    (As soon as they figure out a way to bus them to the US in time to vote in this election.8-)

    • Huh? I thought sea level rise was supposed to a GLOBAL threat.
      It is indeed, but 3/4 of the globe is anyway water, so no problems there.
      The only problems arise at shores, where tide gauges measure what happens.

  17. ““Sea level has already risen by about a foot, 1 foot, in much of the Southeast, which means Matthew’s storm surge was higher, and the flooding was more severe.””
    Does she mean that 1.7mm rise per annum is not significant and therefore a lie? and wishes to give the accurate story of 10 inches since 1880 which is documented somewhere?
    Arithmetic may be her achillies heel.
    Let me see.
    2016 – 1880 = 136 years
    1.7mm x 136 = 231.2 mm
    25.4mm = 1 inch – 231.2 / 25.4 = 9.1 inches
    Is 9.1 inches about a foot?
    Beats me. Maybe she should tell the UN to vacate their headquarters 🙂

  18. Excellent post!
    Hillary is likely to follow in the monumentally ignorant footsteps of Obama who has consistently been wrong on all his assertions during the last 8 years regarding coastal sea level rise acceleration which in fact NOAA tide gauge data shows is non existent.

    • In the world of politics, Hillary knows that what matters is not what is, but what people can be persuaded to think, is.

  19. A bit too ‘Sciency’ with too many facts for the left….. With that many facts causing emotional stress for them, they’ll accuse you of using “Hatefacts” and demand a trigger warning.

    • No it has been unusually mild in East Greenland this fall with strong southerly winds. So all that wet air from the Atlantic gets forced up over the icecap and drops record amounts of snow.
      That is something often forgotten. Glaciers require cold and precipitation. That is why there are almost no glaciers in northern Siberia. It is cold, but too dry.

  20. Remember that part of the reason for recent sea level pile up on the east coast of North America is the current slow down of the Gulf Stream. This is not necessarily associated with warming – more likely the opposite.

  21. All of you have it wrong!! The sea level is rising. But Florida is also rising, so the sea level rise doesn’t show up in America [except during storms].
    How do I know that Florida is rising? The sinkholes are pushing it up!!

  22. Every cubic kilometer of silt deposits can cover area of 1 million square kilometers with 1mm deposit.(1000m x 1000mm). World ocean has 360 million km2. That means 720 cubic kilometers of deposits in oceans will cause rise of world ocean of 2mm per year.
    Take all rivers with silt deposits, all dust from atmosphere and do not forget all the lava from underwater volcanoes.

  23. David Middleton ==> You might like to check and use the National Geodetic Survey’s data collected through their network of Continuously Operating Reference Stations (CORS). Data and maps available, as well as links to processed data in papers: https://www.ngs.noaa.gov/CORS_Map/
    These CORS units tell whether ort not the land mass is in motion and in which directions, included towards and away from the center of the Earth — in other words, is the land itself rising or falling.

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