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Climate Hustle

Doctoring sea level data

What the science says...

Select a level... Basic Intermediate

The claim sea level isn’t rising is based on blatantly doctored graphs contradicted by observations.

Climate Myth...

Sea level is not rising
"Together, these two unaltered [sea level] datasets indicate that global mean sea level trend has remained stable over the entire period 1992-2007, altogether eliminating the apparent 3.2 mm/year rate of sea-level rise arising from the “adjusted” data." (Christopher Monckton)

We have a new entry in the contest for most bizarre "skeptic" argument.  The "Science" and Public Policy Institute ("S"PPI) Monthly CO2 Report for January 2011, edited by Christopher Monckton,  claims on page 29: "Sea level is not rising."

This is of course false.  In fact, sea level is not only rising, but the rise is accelerating.  Immediately below this false claim, the document contains the following figure:

Morner sea level delusion

Notice that the caption claims the blue curve is observational sea level data "up to 1960 according to Professor Morner."  Of course, after 1960 (when the "observations" are apparently just made up) is not only when the "observations" supposedly diverge from the models, but also when they diverge from reality!  Ah, but it gets even worse from here.  On page 33, the document presents what may be my favorite figure of all time:

Monckton batshit insane

Monckton and "S"PPI have taken the sea level graph from the University of Colorado at Boulder which shows a 3.2 milimeter per year sea level rise trend (as is still visible in the bottom right of the graph), rotated it to make the trend look flat, and claimed that this is what the "unaltered" and "uncorrected" data looks like.

It boggles the mind that Monckton and the "S"PPI think they can convince people that sea level has dropped since 1950 based on nothing more than their own unsubstantiated claims and blatantly doctored graphs which are completely contradicted by the actual observational data.

Basic rebuttal written by dana1981

Update July 2015:

Here is a related lecture-video from Denial101x - Making Sense of Climate Science Denial


Last updated on 8 July 2015 by pattimer. View Archives

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Comments 1 to 13:

  1. This explanation is not up to the standards of excellence I would expect from this site. What would be helpful is more explanation in support of the statements that LMVoB (Monckton) has blatantly doctored graphs, notably a discussion of his key claim that "a global isostatic adjustment correction" is open to questioning. He says in the caption to the graph that appears before the second one you show: "The question is whether or not this “correction” is justifiable." Quite. Given this is his justification for tipping the graph like so, I would be grateful if someone with a better grasp of such things than I could furnish an answer.
  2. My own blog entry on this matter
    Response: TC: The comments policy states that:

    "Any link or picture should be accompanied by text summarizing both the content of the link or picture, and showing how it is relevant to the topic of discussion."

    Your post does not meet these conditions. Future posts consisting of a link only and inadequately explaining the content and relevance of the link may be summarily deleted (which is a lot less work for the moderators).

    For the record, the linked post is an extensive discussion of the noted contrarian Niels Axel-Morner's obfustications of the rise in sea level.
  3. I get the impression that this explanation is muddled. The 'myth' statement says:

    "the rate of increase in sea level has not changed since satellites first began measuring it reliably in 1993"
    (i.e. talking about a real but constant rate of increase with time: saying that the derivative dLevel/dTime is constant).

    ... but 'what the science says' gives:

    'The claim sea level isn’t rising is based on blatantly doctored graphs contradicted by observations'
    (i.e. suggesting that the 'myth' is not talking about a rate (derivative) but about the absolute level. Personally I didn't read it that way).

    I don't have much respect for Christopher Monckton, but I'm not sure that his standpoint is being correctly addressed here. And arguably, the 'myth' statement justifies his trick of sloping the graph: it can be seen as a convenient way of illustrating that the line is straight, i.e. no acceleration.
  4. Antwerpenaar:

    If only you were correct.

    The summary of the myth is ambiguous but when combined with the graphs that are part of the SPPI document I think the meaning is clear. At any rate, I suspect you have inadverently mis-paraphrased the myth statement, which cites Monckton as claiming:

    Together, these two unaltered [sea level] datasets indicate that global mean sea level trend has remained stable over the entire period 1992-2007, altogether eliminating the apparent 3.2 mm/year rate of sea-level rise arising from the “adjusted” data. [Emphasis mine.]

    When combined with the SPPI graphs, it is IMO clear that Monckton is claiming sea levels are not rising at all.

    I assume you have cited an actual quote by Monckton as well (in fact, it would not surprise me if it was from the same document that this rebuttal cites), which is probably par for the course from Monckton.
  5. Composer99:

    thanks for the very useful reply. However for clarification: my citations are copied directly from the table on the front page of SkS 'Monckton Myths', hence my comment about these seeming muddled. Could I suggest a clarification?
  6. Ahhhhhh.

    I think you are correct there: the myth Monckton promulgates in the 'Monckton Myths page' is different than the myth he promulgates at the top of this article (surely a Monckton vs Monckton moment if ever there was one).

    However, your point stands: when Monckton claims sea level isn't rising, this is the article to go to. When he claims, as per myth #1 on the Monctkon myth page, that sea level rise is not accelerating, surely there is another, better rebuttal to use. This one might do.
  7. Something has been bothering me for a while, but I've found no mentions in the literature. Maybe someone here has knowledge.

    We know with increasing storms and precipitation causing massive flooding, landslides and topsoil degrading, the latter is talked about as harming agriculture. All the soil washed away eventually ends up in rivers and then the sea. It has volume, it is increasing. Archimedes?

    Is anyone attempting to estimate the volume of loss and its effect on sea level rise added to all the other causes we know about? There are figures for soil loss annually, which one site claimed was the size of Wales, but no volumes and I know nothing about soil scince or erosion. However small, it's bound to add. Additionally, there's coastal erosion which is also adding annually to the eureka effect.

  8. I wonder how Monkton or anyone with a graph they believe disproves rise would care to explain how come the North Norfolk coast is getting increasingly flooded from the North Sea, and the golf course at Brancaster, just to cite one place, is expecting to lose its course by 2020 as it's close to the sea with just dunes protecting. And as no houses on the seaward side of the coast road can get mortgages.

  9. Hi,

    Having grown up metres from a beach in the South Island of New Zealand, I would like to offer my observations, thoughts and a question. I personally have not observed any sea-level rises over 50 years (I'm a 63 year old) and have this link to an article on New Zealand's  most read news website who btw recently published their policy that the science around climate change is "settled". <a href="">News website to publish only climate change friendly opinions and not skeptical viewpoints</a>

    Below is a link to an article on where New Zealand's coastline is rising or falling.


    <a href=""> Is it the land that rises and falls, not the sea?</a>

    I find it difficult to imagine that any amount of erosion is causing a displacement effect mainly because the sea covers four fifths of the earths surface and the deepest point in the ocean is 10.9 kilometers while the highesthe point Mount Everest, is 8.9 km high.

    I would like to be convinced that sea levels are indeed rising (as I have been convinced about increasing levels of residual CO2, explained clearly elsewhere on this site). Is anyone willing to try? Thank-you.

  10. Bart, I find some aspects here a little puzzling. Where has anyone postulated that sea level is rising because of erosion causing displacement? This could only affect very local bays. Seas are rising because of two factors:
    1/ Ocean warming. This causes thermal expansion. Because ocean volume is so huge small changes in temperature easily produce mm of rise.
    2/ Melting ice. Glacier and icesheet losses are well documented.

    As you point out NZ is a lousy place to measure sealevel rise because of tectonics (compare Marlborough sounds -going down - with Kaikoura going up) unless you live in Northland. Even so, on many wide beaches noticing a 10-12cm rise in sea level over 50 years takes a very acute observer.

    So it comes down to what evidence do you accept? The primary evidence is from worldwide network of tide guages (publically accessible) which admittedly needs works to deal with subsidence and station changes. Why are these not convincing to you? Because of issues of land up/down, since the early 1990s, we have relied on satellite altimetry instead though the curves closely match the tide guages. If you dont accept the measurements of sealevel from altimetry, then does that mean you dont accept the results of all the other uses for satellite altimetry either?

    So to disbelieve sea level rise, you have to deny also the measurements in tide gauges and satellites, that the oceans are warming and that the ice is melting. What kind of evidence would you believe?

  11. "I find it difficult to imagine that any amount of erosion is causing a displacement effect"

    You are indeed correct in that skepticism, as the contribution of river sediment delivered to the oceans is about 20 billion tons / year. This sums to about 6 km^3 / yr or ~0.017 mm / yr of sea level rise equivalent (which is about ~1/200 of the current rise rate).

    So if the oceans are not rising significantly due to these natural displacement factors, why is it rising? What then are the actual measured major contributors to sea level rise?

    Let’s look first at what current SLR levels are: 3.2 mm/year.

    Let’s think about what that 3.2 mm/year actually represents, in terms of water volume: 1,184 cubic kilometers per year!

    This means that every 5 years, the oceans are rising by the equivalent volume of twelve Lake Erie’s (484 cubic kilometers)! And over a 10-year period, the oceans will rise by a volume almost equivalent to that of Lake Superior! Wow! And that’s just at current rates of SLR!

    So where are the various contributions to measured SLR coming from? Let’s look at that.

    "Ocean thermal expansion, glaciers, Greenland and Antarctica contribute by 42%, 21%, 15% and 8% to the global mean sea level over the 1993-present. We also study the sea level budget over 2005-present, using GRACE-based ocean mass estimates instead of sum of individual mass components. Results show closure of the sea level budget within 0.3 mm/yr. Substantial uncertainty remains for the land water storage component, as shown in examining individual mass contributions to sea level."

    Unfortunately, due to the measured increases in ice sheet mass losses coming from Antarctica (which have tripled since 2012 alone), the rates of SLR are themselves accelerating:

    "Global sea level rise is not cruising along at a steady 3 mm per year, it's accelerating a little every year, like a driver merging onto a highway, according to a powerful new assessment led by CIRES Fellow Steve Nerem. He and his colleagues harnessed 25 years of satellite data to calculate that the rate is increasing by about 0.08 mm/year every year—which could mean an annual rate of sea level rise of 10 mm/year, or even more, by 2100."

    "This acceleration, driven mainly by accelerated melting in Greenland and Antarctica, has the potential to double the total sea level rise by 2100 as compared to projections that assume a constant rate—to more than 60 cm instead of about 30." said Nerem, who is also a professor of Aerospace Engineering Sciences at the University of Colorado Boulder. "And this is almost certainly a conservative estimate," he added. "Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that's not likely."

    Per Nerem et al 2018:

    "the observed acceleration will more than double the amount of sea-level rise by 2100 compared with the current rate of sea-level rise continuing unchanged. This projection of future sea-level rise is based only on the satellite-observed changes over the last 25 y, assuming that sea level changes similarly in the future. If sea level begins changing more rapidly, for example due to rapid changes in ice sheet dynamics, then this simple extrapolation will likely represent a conservative lower bound on future sea-level change."

    Sea level rise components, from Cazenave et al 2018:



  12. Just one other thought in the question on where land sinks or sealevel rises. Satellite altimetry measures sealevel with respect to the geoid rather than any definition of coast.  This height measurement (often referred to ordinary use as "GPS Height" as height from GPS is likewise) can be determined for tide guages too so you can see whether they are moving up or down with respect to geoid.

  13. Whoops! Brain fart. Altimetry and GPS measurements are made with respect to reference ellipsoid not geoid. Sorry about that. However, effect is same (a reference level independent of land up/down).

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