Coping with Sea Level Rise

The people of Tampa Bay, in order to prepare for all the problems that will come with sea level rise, responded to Florida’s 2015 Peril of Flood Act by having their Climate Science Advisory Panel (CSAP) produce a Recommended Projection of Sea Level Rise in the Tampa Bay Region. They proposed multiple projections, which were then used to estimate how the region, its people, and its facilities were at risk in a recently released study by the Tampa Planning Commission.


noaa-projected-sea-level-rise

The planning commision’s report considers risks which may plague the Tampa Bay region as early as 2040, which includes a threat to homes, businesses, and Tampa General Hospital. That’s serious business.

The projections cover a range of possibilities. The low end is essentially a continuation of the average rise rate over the last 70 years as observed at the St. Petersburg tide gauge. The projections are provided in tabular form, through 2100 in the CSAP report and through 2040 in the report from the Planning Commission. So, we can make our own graph:

projections

The different scenarios are based on expert evaluation by NOAA, the National Oceanic and Atmospheric Administration. Enter Willis Eschenbach, who derides the projections. Here’s an example of Willis Eschenbach’s method of “scientific” appraisal:


Uh-oh, sez I. We are now in the hands of “experts engaged in climate science”, so hide the good silver and watch your wallets …

Perhaps Willis Eschenbach actually believes that the best way to communicate science is to slander scientists you disagree with, by calling them dishonest in as snotty a fashion as possible.

When it comes to actual science rather than infantile slander, the essence of Willis Eschenbach’s is this claim:


Finally, look at the St. Petersburg sea level dataset, or any Florida sea level dataset. None of them show any significant acceleration, despite covering the period of recent warming. Warming but no acceleration of sea level rise … oops.

The St. Petersburg sea level data set in question is from their tide gauge, and shows how sea level has been rising in the region since 1947. Here are annual averages:

stpete

The average sea level rise rate over these 70 years has been 2.7 mm/yr, but Willis Eschenbach mistakenly speaks as though it’s still rising at the same rate. It isn’t. Contrary to what Willis Eschenbach claims, this data set shows significant acceleration. I wonder whether he’s not competent to determine that, or he simply didn’t bother to find out before making his claim.

The linear model on which Willis Eschenbach’s claim is based, the one with a constant rate of rise, is demonstrably inferior to a quadratic model, which includes acceleration:

stpete_accel

The quadratic term achieves statistical significance, which demonstrates that the constant-rise-rate model is not correct — but that’s the basis for Willis Eschenbach’s claims that the present rate of sea level rise there is merely 2.6 mm/yr.

Even if we restrict ourselves to the linear model, the rate Eschenbach uses omits more recent data, so his estimate is out of date. The present linear rate estimate is now up to 2.7 mm/yr. And there’s uncertainty associated with that, as with any estimated rate — something Willis Eschenbach doesn’t mention. The linear model suggests the rate might be as high as 3.0 mm/yr (95% confidence interval).

But the linear model isn’t right; acceleration of sea level rise at this location is a statistical fact. The present rate, estimated from the quadratic model, is 4.65 mm/yr. Of course there’s uncertainty associated with that too — it could be as high as 5.7 mm/yr. Already, in 2016 — not at some future time. Yet Willis Eschenbach insists on using an out-of-date and demonstrably wrong estimate, with no consideration of its uncertainty, to ridicule the projections of genuine experts.

Willis Eschenbach also speaks in rather cavalier fashion about the global rate of sea level rise when he says:


Sea level is rising around the world at something like 8-12 inches (200 – 300 mm) per century.

This is ridiculous. The present rate of sea level rise, worldwide, is over 3 mm/yr (over 300 mm/century), yet Willis Eschenbach speaks as though it’s less than that, possible as little as 2 mm/yr. I wonder whether he thinks all the scientists who measure sea level rise using satellite data are incompetent or dishonest, or he simply didn’t bother to find out the truth before making his claim.

As for the projections which Willis Eschenbach ridicules in such snotty fashion, we can examine them more closely for the time span up to 2040, the period considered in the report from Tampa’s Planning Commision:

projections1

The projections start in 1992, so naturally it’s worth comparing the projections to observed sea level rise since that time as measured at the St. Petersburg tide gauge station:

projections2

Clearly it’s too early to tell which of the projections will be closer to reality. But some conclusions are already evident. First, the observed sea level rise is well in the midst of the range of projections. Second, because proper planning must take worst-case scenarios into account, it’s a good thing the Climate Science Advisory Panel included the high-end projection, to enable area planners to prepare for the extreme trouble which is a realistic possibility. Third, Willis Eschenbach’s ridicule of the projections is contradicted by observational evidence already.

In my opinion, the worst aspect of Willis Eschenbach’s criticism of the projections isn’t his utter scientific incompetence, it’s the snotty attitude which pervades his essay. Just my opinion.

I advise the people of Tampa Bay to begin their preparations immediately. I also advise them to ignore any and all snotty critics who deride the wisdom of actually getting prepared for the changes that are coming.


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33 responses to “Coping with Sea Level Rise

  1. Typical. The data don’t show what Eschenbach wants to see, so he won’t look, except in the most cursory fashion.

  2. I’m confused: If it’s a 2015 report, why do all the projection graphs start around 1990?

  3. Well, it’s pretty clear that he didn’t actually get to know the facts before giving his opinion. I don’t know of Willis Eschenbach but I guess he’s a denier and deniers always avoid checking facts. The graph may even look like it supports his claim, to some people, so he can get away with it and influence people.

  4. It’s curious that the projections start in 1992. That suggests to me that they are based on the old IS92a and IS92b scenarios. These were standard scenarios used in climate modelling before the development of the SRES scenarios (A2, A1F1, B2, etc), which were themselves superseded by the Representative Concentration Pathway scenarios, such as RCP8.5 and RCP4.something.

    I suppose it’s fair to say that nothing fundamental has changed in our knowledge of climate science since then, and in particular there has been little progress in reducing the uncertainty in climate sensitivity, or in resolving the ice sheet response to warming.

    I can’t help but be reminded of what Marx said about philosophers, “The philosophers have only interpreted the world, in various ways. The point, however, is to change it.” and that this applies in a slightly modified form to climate science – the point is to not change the climate.

    • National Tidal
      Datum Epoch:

      The specific 19-year period adopted by the National Ocean Service as the official time segment over which tide observations are taken and reduced to obtain mean values for tidal datums. It is necessary for standardization because of periodic and apparent secular trends in sea level. The present NTDE spans 1983 through 2001 and is referred to as the mid-point or 1992.
      The NTDE is actively considered for revision every 20-25 years

      ———-

      Skeptics go to one place here, and that is subsidence. In the referenced study, it looks like they used an United States Army Corps of Engineers calculator. Has the USACE never heard of subsidence and are they incapable of accounting for it?

      Not that it means a great deal, but the current 1-year rate of GMSLR is 4.11 mm p/yr, and the 5-year rate is 4.97 mm p/yr.

      • Everett F Sargent

        JCL,

        http://www.publications.usace.army.mil/Portals/76/Publications/EngineerTechnicalLetters/ETL_1100-2-1.pdf

        Subsidence? Check.

        RSL is what counts in coastal planning and designs thereof.

        [Response: Relative sea level change is a combination of subsidence/uplift, and change of the sea surface height. Anyone who uses subsidence/uplift to deflect attention from the undeniable rise of sea surface height, and/or its acceleration, is either dishonest or really, really stupid — or both.]

        It’s fine to fit a non-linear curve to the tide gage data, just don’t extrapolate it 84 years for planning or design purposes.

        [Response: The projections are not an extrapolation of curve fits, except for the lowest projection which extrapolates the linear rate since 1947. They’re more interpolations, so that if net sea level rise by 2100 reaches a certain level, we have an approximation of where it will be in intervening years.

        The real usefulness of the quadratic fit isn’t that it gives a precise forecast for future sea level change. It’s that it disproves the false claim (by Willis Eschenbach) that there’s no acceleration in any tide gauge data set from Florida.]

      • Everett F Sargent

        [Response: Relative sea level change is a combination of subsidence/uplift, and change of the sea surface height. Anyone who uses subsidence/uplift to deflect attention from the undeniable rise of sea surface height, and/or its acceleration, is either dishonest or really, really stupid — or both.]

        I didn’t bring up the issue of subsidence. :( JCL did. Subsidence is part of the planning guidance. That is all.

        [Response: The projections are not an extrapolation of curve fits, except for the lowest projection which extrapolates the linear rate since 1947. They’re more interpolations, so that if net sea level rise by 2100 reaches a certain level, we have an approximation of where it will be in intervening years.

        The real usefulness of the quadratic fit isn’t that it gives a precise forecast for future sea level change. It’s that it disproves the false claim (by Willis Eschenbach) that there’s no acceleration in any tide gauge data set from Florida.]

        I didn’t say the projections were an extrapolation of the curve fit, now did I?

        Abjectly, it does NOT give a scare quotes precise forecast scare quotes, it is simply a curve fit for the known data with associated confidence intervals for that known data period. Care to extrapolate those (expanding at greater than linear rate) confidence intervals another 84 years? TIA

        It’s called planning guidance for a reason. It includes the lowest (linear extrapolation of RSL) all the way up to 2.0m by 2100. Federal, state and local concerns are free to choose whatever they want, given the nature of past-present-future infrastructures. That’s one reason why the guidance is so broad.

      • What I was pointing out that subsidence is the place many skeptics go to hide from the reality of sea level rise. It would be ridiculous to think that the United States Army Corps of Engineers does not know about subsidence, but that is exactly what many skeptics think.

        The other place skeptics go to hide from the realty of sea level rise is their speculation that measuring SSH from satellites with altimetry is probably hard, which is why they hire scientists to do it instead of high school dropouts.

      • “… their speculation that measuring SSH from satellites with altimetry is probably hard…”

        And which assorts so strangely with their speculation that measuring surface temperatures with remote sensing is probably easy.

  5. Nic Lewis thinks that Willis has a strangle hold on Floridian SLR

    niclewis January 15, 2017 at 12:35 pm
    Congratulations on another excellent article, Willis.

  6. I have hoped that Tamino would write about Tampa Bay since I live there. As usual you do a great job. It will be interesting to see what the projections of a report from neighboring St Petersburg say since that city is much more low lying than the City of Tampa (covered by this report). This report is especially interesting to me since I hope to live until 2040, the end of the time period where they assess affects on land. Your graph of actual sea level rise compared to projected is especially interesting.

    On page 5 of the projection of Sea level Rise (linked in the first paragraph of the OP) it states that they used the IPCC Fourth assessment report to set their projections. I presume that they started the projection report before the IPCC Fifth report was released. In the Fourth IPCC report they did not consider sea level rise from melt of the great ice sheets of Greenland and Antarctica. The Fifth report’s assessments of sea level rise were significantly higher than the data used for this report. Since the Fifth assessment was released, new data shows that the ice sheets are unstable and higher sea level rise is likely.

  7. Willis Eschenbach? Remind me, who’s he in the professional, trained and experienced climatology/oceanography literature?

    Right…

    On the acceleration… although a quadratic fits, my inclination would be to follow physics and nature, and assume a sigmoid response. The plateau might be a little difficult to pin down at this point in proceedings, but the trajectory to at least the point of inflection would probably be close enough that any policy decision could be reliably based on such projections.

    [Response: As George Box said, all models are wrong, some models are useful. The usefulness of the quadratic model is that it enables us to negate the linear model and establish acceleration. But I doubt sea level will follow a quadratic (i.e. constant-acceleration) model. I expect the acceleration will increase in the next few decades.]

  8. Obviously Willis has got it wrong (yet again), but even if he had it right he’s still admitting the sea level is rising. That means it will still displace people, still cause billion dollar disasters, still require preparation for those countries that can afford it and geopolitical destabilization for countries and their neighbours that can’t adequately prepare for it.

    So, I’m not sure what exactly his point is. Why not say “I think the lowest estimate is the correct one, and we’d better prepare for that”, and avoid the petty insecure snark? And if he were had the mindset of a scientist he’d add, “I could be wrong so better prepare for the next higher estimate, at least”.

    Seems he manages to fail not just at science, but also at playing one on a blog.

  9. Luiz Da Silva

    Again it appears that that the climate alarmist mind set is at play here. Choosing and picking what data set to use is the preferred method of disinformation. The earth’s climate has been changing for the last 4.5 billion years and will continue to do so with or without human interaction. The main factor impacting the climate is and will continue to be the sun’s output. As to preparations for imminent sea level rises for the Florida area it would be better to worry about the next hurricane.

    [Response: Again it appears that that the climate denier mind set is at play here. If you’re trying to accuse me of disinformation by “choosing and picking” the sea level data from the St. Petersburg tide gauge, go accuse Willis Eschenbach — that’s what he chose to focus on, and what he claims shows no acceleration — a mistaken claim made, apparently, without even having done any study of the data he himself refers to.

    Hurricanes are unavoidable, and the next one to hit the Tampa Bay area will bring trouble. Pity that climate deniers can’t seem to comprehend that sea level rise makes their impact worse, by increasing the storm surge and worsening the flooding. It’s both foolish and pathetic disinformation to use the devastation of a hurricane to downplay the need to understand how much worse it will get.]

    • Projection as a trick is really overrated, Luiz. Worked for a while under Rove, but people really are on to it now and it doesn’t even fool the self deluded.

      Question for you Luiz: How many of those 4.5 billion years of ever changing atmospheric conditions could we place you outdoors somewhere on the planet and expect you to live more that an hour? (Hint: It’s not a game you want to play.)

    • The main factor impacting the climate is and will continue to be the sun’s output.

      And how would you characterize solar ‘output’ quantitatively, with respect to climate? What is the variability of solar ‘output’? How does it correlate with ‘climate’ over the last several decades? We breathlessly await your analysis.

      Well, maybe not ‘breathlessly.’ I’m guessing it may take a while.

      Hint:

      http://woodfortrees.org/plot/wti/mean:13/plot/pmod/offset:-1366/mean:13

    • Tamino wrote in reply to Luiz: “If you’re trying to accuse me of disinformation by “choosing and picking” the sea level data from the St. Petersburg tide gauge, go accuse Willis Eschenbach — that’s what he chose to focus on”

      Which Luiz would have known had he bothered to read your post before commenting. Unfortunately, I’ve found that not only is reading comprehension not a strong suit among climate science deniers like Luiz, many of them don’t even bother to read the original post at all before commenting. As a result they tend to score a lot of own-goals, as Luiz did, even before his back-handed “it’s the sun” comment in the midst of current record temperatures while solar output is at a modern low, demonstrating a self-imposed ignorance that is simply impervious to reality.

    • LDS: The main factor impacting the climate is and will continue to be the sun’s output.

      BPL: We have been measuring the sun’s output from satellites for more than 60 years, and for all that time, it has been even or dropping, aside from the 11/22 year sunspot curve. Sunlight cannot in any way explain the global warming of the last four decades.

      http://bartonlevenson.com/Sun.html

      • skeptictmac57

        “BPL: We have been measuring the sun’s output from satellites for more than 60 years, and for all that time, it has been even or dropping, aside from the 11/22 year sunspot curve. Sunlight cannot in any way explain the global warming of the last four decades.”

        Yes, I don’t know why deniers keep pushing this long debunked talking point.
        I often wonder if the more ‘informed’ deniers like to use this, to dupe the less informed by making them think that climate scientists are saying that the excess heat energy isn’t originating from the sun, but coming directly from CO2, rather than being trapped.
        “Of course the dang ole sun is creatin’ the heat, so why are them crazy scientists sayin’ it’s our fault!!!”
        It’s just common sense…right?

  10. “Nic Lewis thinks…”

    Isn’t there a better verb?

  11. skeptictmac57

    One of the ‘cleverest’ moves that the fossil fuel industry pulled, was to frame the concerns of climate science as ‘liberal’ and coming from Democrats only.
    Ironically, they should have been seen as being conservative (in the truest sense).
    When I listen to the arguments against consensus science, they almost always have this snarky, dismissive and libelous, air to them, whether it is against evolution, vaccines, GMO’s or climate science, the attitudes against them is nothing short of grand conspiracy theory thinking.
    But when I listen to the actual scientists in those fields talk about their work, they are straightforward, data driven, nuanced, talking in ranges of probabilities and acknowledging uncertainties and polite and even often meek. Just the opposite of the way they are being demonized by their opponents.
    That difference is always a red flag for me, and I struggle to understand why the average person on the denial side of these issues do not pick up on this.

  12. Looks to me like Eschenbach is Presidential advisor material.

  13. Scepticmac- you’re spot-on about the abuse of the word ‘conservative,’ which has become a completely misleading label (a usage that’s become standard for the mainstream press). What it seems to mean now is extreme radicalism and a defense mechanism for that radicalism that depends on the self-serving rejection of overwhelming evidence that their ideologically driven policies will not work out well… Given that public memory has failed (I recall a recent poll showing that most Republicans believe the stock market declined during the Obama Presidency), I fear the chickens will come home to roost, but very few will have any clue as to where they flew in from…

  14. ” If you’re trying to accuse me of disinformation by “choosing and picking” the sea level data from the St. Petersburg tide gauge, go accuse Willis Eschenbach”

    Maybe Mr. Eschenbach has looked at this one?…

    https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=8726520

    … where NOAA itself does a linear fit… no parabola around?

    The figure’s caption, not written by Mr. Eschenbach, reads:

    “The mean sea level trend is 2.66 millimeters/year with a 95% confidence
    interval of +/- 0.25 mm/yr based on monthly mean sea level data from
    1947 to 2015 which is equivalent to a change of 0.87 feet in 100 years.”

    0.87 feet = 265.2 mm

    Case closed… all the rest is misinformation or paranoia at best.

    [Response: NOAA reports the result of a linear fit to every tide gauge. They make no claims about the significance, or lack of same, of acceleration. Willis Eschenbach did — and got it wrong. Apparently he hasn’t analyzed the data properly, if at all. It seems the same goes for you.]

    • @tamino

      “They make no claims about the significance, or lack of same, of acceleration. Willis Eschenbach did — and got it wrong. Apparently he hasn’t analyzed the data properly, if at all. It seems the same goes for you.]”

      Actually I have looked at it… and there is no noticeable acceleration, some peer-reviewed papers come to the conclusion that many tide gauges show a deceleration of the rise.*

      [Response: In case you weren’t paying attention, the subject was the tide gauge data from St. Petersburg, FL. Yes there is acceleration. Did you actually look at it and just get it wrong? Did you not understand what the topic was?]

      I do not spend any time looking for links about this studies, as I am perfectly sure that an expert in the matter like you are knows about them perfectly.

      [Response: I’ve dealt with garbage, like that from Houston & Dean for example, before. It’s a pity you pretend that their (and others’) publications are informative. Or were you actually taken in?

      Careful study of many tide gauge records, and of global estimates, shows that during the 20th century sea level has shown both acceleration and deceleration (at different times). I’ve blogged on the topic more than once, but won’t bother to provide links, to save you time since you already know how to ignore the truth perfectly.]

      The only thing left to do is to understand why you pretend that they do not exist.
      Cheers.

  15. I encourage everyone to go defrost their freezer. Mine has wire racks. It melts for a while, then ice starts falling off the racks and bounces out on to the floor. As chunks of ice bounce out onto the floor, the process goes much faster than I expect. Always! Always!, and I have been doing this since a Chem E professor demanded that we go home and defrost our mother’s freezer more than 50 years ago. I am a slow learner.

  16. Michael Hillinger

    Tamino, I wonder what your take is on this analysis. It was done by a conservative “think tank” as a response to the New Hampshire Coastal Risk and Hazards Commission. The article at http://www.unionleader.com/environment/free-market-think-tank-pushes-back-on-coastal-flood-risk-report—20170124 has links to both the report and the analyses.

    Thank you.