A Level Look At Sea Levels

Head for the hills folks! Sea levels are rising. But first read Ed Caryl’s latest essay on sea levels. It sure helps ignoring the climate catastrophe cultists for a few minutes and taking a sane look at the data.

A Level Look At Sea Level

By Ed Caryl

Figure 1: Sea level rise since the last glacial maximum 20,000 years ago. (Chart source: http://en.wikipedia.org/wiki/File:Post-Glacial_Sea_Level.png

One of the tenets of the AGW crowd is the idea that sea level rise is going to be catastrophic in the next 100 or 200 years, drowning our coasts and harbors, and in the case of low-lying countries, like The Netherlands, whole countries. These are not the facts.

Figure 1 shows the sea level rise over the last 20,000 years. In the last 8 thousand, the curve looks flat. It looks like there has been no rise since civilization began, and that the recent rise of about 20 cm (Figure 2) since 1900 is “unprecedented.” That is not true. The sea level has risen and fallen several times in the last few thousand years.

Figure 2: Recent sea level rise. Chart source: http://en.wikipedia.org/wiki/File:Recent_Sea_Level_Rise.png

In Figure 3, one can see that the sea level did not abruptly level off after the rather swift rise as the major continental glaciers melted, but slowly continued to rise, with one episode of falling between 3 and 4 thousand years ago.

Figure 3: Magnified view of sea level rise in the last 8,000 years. Chart source: http://en.wikipedia.org/wiki/File:Holocene_Sea_Level.png

A closer look at the last 2000 years is wanted. An article describing the sea level at Barrow Alaska was found. Here is the abstract in full:

Eustatic rises of sea level between A. D. 265 and 500 and between A. D. 1000 and 1100 caused the formation of raised beaches. After the first rise, sea level dropped about 2 meters below the present level, permitting Eskimo settlement of Birnirk about A. D. 500. The second rise of the ocean flooded Birnirk. At present, sea level is about 0.6 to 1.0 meter below the high water levels; the ocean partially floods Birnirk.”

The rises and falls at Barrow mirror the Roman Warm Period, the Dark Age Cool Period, the Medieval Warm Period, and the last fall in sea level in the Little Ice Age, with a slow rise since then. (See From Hockey Sticks to Boomerangs for the temperatures during this period.) But we are still below the high water levels seen at Barrow. These events are somewhat visible in the data points of figure 3, but the author of that chart has chosen to use a straight line to depict the sea level for the last two thousand years, not showing the natural variation.

 The same rises and falls happened in the Fenlands of eastern UK. This description is from Wikipedia. The Roman period in the UK was from 43 CE to 410 CE, well into the Dark Age Cool Period.

The peak of the water levels in the fens was in the Iron Age; earlier Bronze and Neolithic settlements were covered by peat deposits, and have only been found recently.[11] During the Roman period, waters levels fell once again, and settlements were possible on the new silt soils deposited near the coast. Though water levels rose once again in the early medieval period, by this time artificial banks protected the coastal settlements and the inland from further deposits of marine silts, though peats continued to develop in the freshwater wetlands of the interior fens.[12]

 Then there are the Roman fish pens. Described at this site, but the story is all over the internet as proof of AGW caused sea level rise. It proves no such thing.

‘The Romans dug these fish pens into bedrock, and the water line in these well-preserved structures shows that the sea level along the Italian coast 2000 years ago was 1.35 metres below today’s levels. “They were used for only a very short time, so they make rather nice markers,’ says Lambeck.”

He then analysed how land elevations changed along the Italian coast due to both plate tectonics and the after-effects of the last ice age. In a paper to appear in Earth and Planetary Science Letters, he concludes that geological processes affecting land levels over the past two millennia accounted for 1.22 metres of the change, which means that the global sea level rose by 13 centimetres.”

The only problem with this story is that the sea level changed several times in the intervening years, both up and down. The fish pens are just one marker in time. They were used only for a short time because after that they were either above sea level and dry, or below sea level and unusable. Is there a chart of sea level over the last 2000 years? There is this one at CISRO, but the error bars are very long and it shows nothing useful. We only begin to get good data from tide gauges in the last 300 years.

 A problem with measuring sea level is that isostatic rebound, post-glacial rebound, or glacial isostatic adjustment (GIA), is still happening. It affects tide gauge readings all over Europe, especially in Scandinavia. One way to correct for this is to use GPS readings to find the actual earth movement and subtract that from the tide gauge measurements. When this is done, the real sea level rise in recent years begins to dwindle. This quote is from the abstract of Geocentric sea-level trend estimates from GPS analyses at relevant tide gauges world-wide.

Sea level change in the era of the recording tide gauge. Int. Geophys.Ser., 75, pp. 37–64.] rules, whose estimate is 1.84±0.35 mm/yr after correction for the GIA effect [Peltier, W.R., 2001. Global glacial isostatic adjustment and modern instrumental records of relative sea level history. Int. Geophys. Ser., 75, pp. 65–95.]. We obtain a value of 1.31±0.30 mm/yr, a value which appears to resolve the ‘sea level enigma’ [Munk,W., 2002. Twentieth century sea level: an enigma. Proc. Natl. Acad. Sci. U.S.A., 99(10), pp. 6550–6555]. © 2007 Elsevier B.V. All rights reserved.

S. Jevrejeva et al (Figure 4) did another sea level reconstruction using several European tide gauges and correcting for GIA in 2008. This shows a steady rise of about 300±100 mm since 1800. This is about 1.5±0.5 mm/year. This is a steady rise since the end of the Little Ice Age, with no unusual rise after the increase in CO2. This natural rise began long before mankind began burning fossil fuel in earnest.

Figure 4. The sea level since 1700. Data source: Jevrejeva et al. (2008) For the plot with error indication, go to: http://www.psmsl.org/products/reconstructions/jevrejevaetal2008.php

Is sea level rising? Yes, as it has been since the end of the little ice age 200 years ago. It will continue to rise. The remnant glaciers will continue to melt until the next cool cycle. But there is no catastrophe. At 1.31±0.30 mm/year, or 1.5±0.5 mm/year, if the trend is linear, it will be up 10 to 20 cm by 2110. The Dutch will need to put more blacktop in their dike roadways, which they normally do anyway, several times in the next 100 years. But if the current solar minimum continues for a few years we won’t need to worry about it. We will be in a cool cycle.

Anticipating questions, these are provided:

What about Bangladesh? The river silt has kept up with sea level rise so far, and will in the future, in fact, 250 years ago, much of Bangladesh was flooded all the time. To learn more look: here, here, here, and here.

What about the Pacific Islands, the Maldives, etc? Coral grows much faster than 2 mm/year, and has kept up with sea level rise so far, and it will in the future. Many of those islands are only there because of coral growth.

What about our harbors? Infrastructure is continuously wearing out, being torn down, and rebuilt. The docks of 1700 are no longer there. They have been replaced, 300 mm higher.

30 responses to “A Level Look At Sea Levels”

  1. mindert eiting

    Thanks, Ed. Your article shows the methodological principle that with good research bogus claims disappear as snow for the sun. By the way, Amsterdam was born in the thirteenth century when people started peat digging in the western part of The Netherlands behind sand dunes protecting us from the sea. Water is our arch enemy but we still have dry foots here.

  2. Pointman

    @Pierre. OT I know but let’s get behind Jo Nova’s initiative.


    Worth a topic?


    1. mindert eiting

      Sit on my butt? I was doing the laundry with a 60-lines GW-BASIC program.

      For each weather station on earth, in the past and the present, you can compute (or obtain) monthly means. Take some monthly mean in some year and compare, for the same station, that value with the mean of the same month one year ago. For example, take for a station in The Netherlands the difference of the means in January 1800 and January 1799. I do not have the room here to explain that this is a best method. These differences can be collected throughout the year per station and next over all stations on duty in that year. The result is an annual distribution of differences. The mean of that distribution can be used for cumulatively constructing a time series of anomalies.

      Don’t forget to compute for each year the median, the variance, and the skewness of the distribution. You will find that in many years the distributions are extremely skewed, both positively and negatively. You can even make a time series of the skewness statistics, showing something like shock waves during an earthquake. The phenomenon can be found everywhere, for example in 1764. Extreme outliers push and pull the means above or below the medians, causing spurious temperature changes of more than half a degree Celsius per year. Increasing the number of stations is of no help because bias is not the same as error.

      Define any monthly difference of more than plus/minus ten degrees Celsius as an outlier. Next, determine the number of outliers as function of month. You will find in the GHCN data base that these are concentrated in the winter months, January (31 percent), February (26 percent), December (22 percent), March (9 percent), November (9 percent), etc., with the least in June (0.2 percent).

      Just construct a time series of global temperatures (as anomalies) using differences obtained from April through September (summer-series). Compare this one with a time series obtained from October through March (winter-series). Compute for both series (a) the variance of annual anomalies and (b) slope of linear regression of anomalies on time.

      In the GHCN data base you will find for the years 1701-2010, variance summer-series 0.420, variance winter-series 0.899, slope summer-series 0.003, slope winter-series 0.007. Therefore, in this full epoch the earth (mainly Northern hemisphere) warmed with outliers twice as much as without outliers. Regression slopes of anomalies on the years 1961-2010 are 0.018 and 0.026 respectively.

      I used a crude dichotomy in order not to lose too much information. Of course, I also made a time series based on the month June and January only. We will get now greater variances because of additional error variance caused by less observations.

      Variance June-series 0.606, January-series 4.402. Full-range-slope June-series -0.001, January-series 0.012. The latter tells that during 1701-2010 the earth warmed with 1.2 degrees Celsius per century, the former that the earth did not warm at all.

      In the June-series with considerable error, the regression slope of anomalies on the years 1961-2010 equals 0.014, in the January-series with the most error 0.050.

      The more outliers, the more warming. With the most outliers, the earth warmed in the past fifty years with 5 degrees Celsius per century. Without them it is 1.4 degrees Celsius per century. We have to conclude that AGW is based on poor data handling.

  3. Jimbo

    Not only has “The river silt has kept up with sea level rise so far,..” but the country has gained landmass over the past 30 years. See here, here and here.

    Pacific Islands
    These coral island atolls exist BECAUSE of sea level rise and most have actually grown or stayed their ground:

    New Scientist – June 2010
    “For years, people have warned that the smallest nations on the planet – island states that barely rise out of the ocean – face being wiped off the map by rising sea levels. Now the first analysis of the data broadly suggests the opposite: most have remained stable over the last 60 years, while some have even grown….During that time, local sea levels have risen by 120 millimetres, or 2 millimetres per year on…

    The dynamic response of reef islands to sea-level rise
    Results contradict existing paradigms of island response and have significant implications for the consideration of island stability under ongoing sea-level rise in the central Pacific. First, islands are geomorphologically persistent features on atoll reef platforms and can increase in island area despite sea-level change.

    Solomon Star – March 5, 2009
    When the sea rises, the atoll rises with it, and when the sea falls, they fall as well.

    Human induced factors that can lead to sea water inundation, intrusion and erosion:
    Sand mining and gravel extraction for the construction industry
    Blasting boat passages
    Impacts of recreational divers
    Unsustainable over-extraction of fresh water from the lens
    Over fishing of beaked fish which create sand which is vital for island formation

  4. R. de Haan

    New Ocean reference page at WUWT

    It needs to be said that at this moment sea level rise has stopped.
    In fact a sea level decline is expected.

    During the last Ice Age sea levels were much lower than today.
    All the water was caught up in the ice caps that covered the continents over two miles thick.

    Sinking sea levels are a sign for increased ice concentrations on land based ice caps and glaciers.

  5. Brian G Valentine

    Thank you very much for this. It provides the underlying and historical basis for what everyone who lives in harbor villages and island beach front property already knows to be true.

  6. Edwin Adlerman

    And we can assume that sea level rise will remain linear because…..???

    1. Ed Caryl

      I don’t think it will remain linear. If the cycles of the last 2000 years are repeated, sea level may go down.

    2. DirkH

      You are saying that because some AGW believers *postulate* a catastrophe, we should all take this as the likely outcome? No, it’s the AGW believers job to show that there will be a change in trend. You’re trying to turn the table on us; the latest strategy of the AGW believers.

  7. Green Sand

    Anybody know why University of Colorado has gone all shy?
    Last data appears to be Sept 2010

    2010.7415 25.560

    I know Colorado is a long way from the sea but…

    Also JK at Inconvenient Skeptic thinks that acceleration may have turned into declaration:-

    Sea Level Deceleration: Inverted Barometer


    1. Green Sand

      For “declaration” please read “deceleration”

  8. R. de Haan

    16. Februar 2011 at 20:23 | Permalink | Reply
    You are saying that because some AGW believers *postulate* a catastrophe, we should all take this as the likely outcome? No, it’s the AGW believers job to show that there will be a change in trend. You’re trying to turn the table on us; the latest strategy of the AGW believers.”

    I agree 100%.

    The predicted sea level rise is the achilles heel of the entire AGW doctrine.
    In 1986 when the Climate Catastrophe was declared they came up with the Dome of Cologne flooded with water from the North Sea.

    Imminent Climate Catastrophe they said.

    This is over 26 years ago and nothing, absolutely noting has happened.
    Every single sea level rise example from Tuvalu to Bangladesh has been debunked.

    The warmists are a bunch of freaking liars and we should treat them like that. No surrender to lying freaks.

    If we give in and make them half way on any of the subjects from Carbon Trade to Green Energy we sign our own death sentence.

    Germany is set for 90% bio fuels by 2020 and 1 million electric cars by 2016. We won’t make that. We will be completely bankrupt against that time. Just prey for very hash winters and a few VEI 6 or 7 volcanic eruptions to stop this madness because the doctrine that is descending upon us is a mass killer in the making.

    We will see the first famine’s this summer in all those countries where people have to survive on 2 US dollar a day.
    Bangladesh, India, Egypt, Pakistan, and a bunch of Asian countries and Africa. People will starve not only because they can’t afford food any longer but because we in the west continue to boost crop based bio fuel production. Just remember Obama’s State of the Union.
    Just remember what Merkel has promised.
    Many countries will order bigger stocks than normal to prevent further price hikes and create food security but the effect will be a further rise
    of price levels.
    Today our food stocks have reached the lowest level since the second World War and we only need a small disruption, a drought of an early frost in major wheat lands and people will start to die like flies.

    Mark my words.

    If you have any doubts:


    1. Brian G Valentine

      How much freaking money have we flushed down the toilet because of green pork heads?

      How much more will we need to?

      Name a parasitic disease more costly than green pork heads – in the history of the Universe.

      Go ahead, name one.

  9. R. de Haan
  10. Brian G Valentine

    My wife gets angry with me for getting angry at – green pork heads.

    Being “nice” them only encourages them to run rampant. They don’t respond to a thing – except getting tough on them. Time to fight back.

  11. Edwin Adlerman

    A more recent version by Woppelmann came to a number of 1.61 mm/yr:

    >But if the current solar minimum continues for a few years we won’t need to >worry about it. We will be in a cool cycle.

    If TSI and surface temperature suddenly became correlated since 1970, that’s news to me. Lockwood even updated his paper about a year ago.

  12. Brian G Valentine

    “However, the popular idea (at least on the Internet and in some parts of the
    media) that solar changes are some kind of alternative to GHG forcing in
    explaining the rise in surface temperatures has no credibility with almost all
    climate scientists.” – ibid. p.22.

    The Fallacy of the False Dichotomy. Do you think?

    1. Ed Caryl

      There is this paper by Lean and Rinn, but they didn’t realize that we were already in a minimum.
      When they wrote the paper, they thought the minimum would not happen until after 2014. Expect a revision.

      1. Brian G Valentine

        How much of this stuff would see the light of day in “peer” review if it had to withstand two sentences of justified criticism

        Like none of it, that’s what

  13. Brian G Valentine

    Here’s a photo of some nuclear waste


  14. Edwin Adlerman

    >How much of this stuff would see the light of day in “peer” review if it had to >withstand two sentences of justified criticism

    It already did. You’re perfectly welcome to submit a rebuttal. Please add some pictures of ‘nuclear waste’, as it will enhance your credibility.

    PS. If you really are adjunct faculty, how come you are not listed in the University Directory or in the Engineering Dept or anywhere within the entire Department? Is that a secret Heartland Institute/DOE petroleum assignment, or [-snip]

    1. Brian G Valentine

      Because the web sites are being updated, I was absent on assignment in Iraq.

      I work for the US Department of Energy, Office of Energy Efficiency and Renewable Energy.

      I teach part time at the University of Maryland, Department of Mechanical Engineering. I am teaching a course this semester together with another professor.

      For further details you have to write me personally.


      1. Brian G Valentine
        1. Brian G Valentine

          By the way Mr Alderman,

          Thank you for investigating me on the Internet,

          this demonstrates your commitment to finding out the truth, inspired by a commendable skepticism.

          Now if you’d only demonstrate that level of skepticism to many of the AGW-related studies, I am quite sure you would be convinced of their exaggeration in no time at all. : )

  15. Edwin Adlerman

    >There is this paper by Lean and Rinn,

    Good catch, forgot about that one. However, the conclusion is still reduced warming, eh?

    1. Ed Caryl

      They were following the prediction of two years ago, not what actually happened. Expect a revision.

  16. Ike
    1. Brian G Valentinw

      As well, there’s a lot of excitement in the US about new technologies to discover and extract natural gas.

      That’s a good thing. Here is a natural gas dilemma in the US:

      California relies on ethanol shipped by trucks from Montana and elsewhere. California would like to process their own ethanol from corn starch. They cannot. The reason is, there is not enough natural gas to meet demand of both gas turbine electric power generation and ethanol distillery.

  17. Edwin Adlerman

    >Thank you for investigating me on the Internet,

    Trust but verify!

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