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Climate Hustle

Monckton Myth #8: Rising sea levels

Posted on 27 January 2011 by Rob Painting

Regular readers will know the drill by now, this is one of a series of posts responding to a number of claims recently put forth by British climate skeptic Chris Monckton, in response to an article in the Australian by Mike Steketee. So let's begin.


Monckton - "In fact, the rate of increase in sea level has not changed since satellites first began measuring it reliably in 1993"

Chris Monckton is correct that the rate of sea level rise has not accelerated throughout the 17 year period of satellite altimetry, however it is still rising in a linear fashion at around 3mm per year. His suggestion that the tide gauge data is not reliable isn't borne out by simple fact checking however, the tide guages are still in use and their data overlap the period of satellite observation. Both satellites and tide guages are in broad general agreement.

Figure 1. - Global mean sea level since 1870. Courtesy of CMAR CSIRO 


Monckton - "It (satellite altimetry data) is a dizzying 1 ft/century – not vastly greater than the 8 inches/century that had previously been inferred from tide-gauges."

The insinuation here is that the rate of sea level rise has not changed appreciably over the timespan of record keeping. This is not correct. Church & White 2006 found that the rate of sea level rise accelerated throughout the 20th century. Merrifield 2009 also found a 20th century acceleration and another study (Jevrejeva 2008) show that the acceleration began as far back as the 18th century.



Figure 2. Sea level reconstruction since 1700 from Jevrejeva 2008.  Shadow represents the errors of the reconstruction & fitted curve is a second order polynomial fit.


Monckton - "A recent paper has confirmed what marine biologists had long suspected: coral atolls simply grow to meet the light as the sea rises, and some of them have even gained land mass recently according to a just-published scientific paper."

This reference is to Webb & Kench 2010, in which the authors examined aerial photos and satellite images of 27 coral atoll islands in the South Pacific taken decades apart. Despite rising sea level rates in the region of 2 mm per year, only 14% of islands decreased in land area. Measurements of height changes were not made.

How this negates current concern about sea level is rather a mystery; sea level rates until now have been relatively small but are expected to increase as global temperatures rise and ice melt accelerates. Rates projected for this century range from 8 - 18mm per year (Grinstead 2008, Vermeer & Rahmstorf 2009) and coral reefs are actually in very poor shape, particularly from warm-water induced mass coral bleaching and ocean acidification. Globally coral are in decline, with about 40% of coral cover being lost in the last 3-4 decades, and recent studies have shown that coral growth rates on the Great Barrier Reef, Australia (De'ath 2009), South East Asia (Tanzil 2009) and the Caribbean (Bak 2009) have dropped in the last couple of decades. That coral can cope with the with the projected rate of sea level rise when they are in crisis (Veron 2009) and at elevated risk of extinction (Carpenter 2008) is somewhat far-fetched.


Monckton - "Professor Niklas Mörner, who has been studying sea level for a third of a century, says it is physically impossible for sea level to rise at much above its present rate, and he expects 4-8 inches of sea level rise this century, if anything rather below the rate of increase in the last century."

Mörner is a retired professor from the University of Stockholm. who has recently criticized current scientific work on sea level. Work by Vermeer and Rahmstorf contradict Mörners' claim. Examining sea level and it's relationship with global temperature, they develop a method for estimating sea level which accurately simulates observed sea level rise. When this method is applied to warming anticipated this century, an acceleration of sea level is projected. 


Figure 3. -  From Verrmer & Rahmstorf 2009. Sea-level rise from 1990 to 2100, based on IPCC temperature projections for three different emission scenarios


Monckton - "In the 11,400 years since the end of the last Ice Age, sea level has risen at an average of 4 feet/century, though it is now rising much more slowly because very nearly all of the land-based ice that is at low enough latitudes and altitudes to melt has long since gone."

The Greenland and Antarctic ice sheets have more than enough ice to cause a jump in sea level rates. The question is how quickly that ice might melt. We can look at the last interglacial, the Eemian for insight, because Earth's land, plants, ice and circulation were similar to today. 

At the height of the last interglacial (about 115,000 -130,000 years ago), global temperatures were 1-2 degrees C warmer than now, resulting in less global ice than today at its peak because of different Earth orbital cycles. Sea level rises at times during this period exceeded 36mm per year (Blanchon 2009 ) . Kopp 2009 estimate that global sea levels rose 6 to 9 meters higher than now, and the authors commented:

"The results from the LIG (Last Interglacial) suggest that, given a sufficient forcing, the present ice sheets could sustain a rate of GSL (global sea level)  rise of about 56–92 cm (5.6-9.2 mm per year) per century for several centuries, with these rates potentially spiking to higher values for shorter periods."

Rising sea levels are a legitimate concern based on the best scientific evidence available; idle speculation by Chris Monckton is not a reasonable basis to suggest otherwise.

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Comments 1 to 50 out of 58:

  1. Is it right to use the word 'skeptic' to describe Monkton? How can somebody that always searches for arguments for the same result, less warming, be a 'skeptic'? Especially if the arguments are so consistently weak or invalid?

    If 'contrarian' and 'denier' are considered words to be avoided, to keep discussion polite .. what descriptive word could one use? Anti-warming advocate? Anti-warming lobbyist? The least one should do is not to honour him with the title of 'skeptic'.
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  2. Nicely done Rob.

    Err, how does Monckton's argument (promoted thanks to Anthony Watts) that the oceans are allegedly cooling tally with his concession that sea levels are rising? Oh right, the contradictory nature of arguments made by many "skeptics" is to be expected. Identifying Monckton as a "skeptics" might be too generous though.

    "coral atolls simply grow to meet the light as the sea rises"

    Does this claim not totally ignore the negative impacts of bleaching and ocean acidification on the corals' ability to reproduce and grow?
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  3. We need to be careful here. Sea levels have been generally rising for the past 20,000 years. It's not unusual. It changes with ocean temperature, but also shifts in the Earth's plates. Then there's the thousands of underwater volcanos.

    It's rising in some areas, and lowering in others (eg Scandanavia). It seems there's bigger forces involved than temperature effects.
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    Response: We can use observations to calculate the various causes of sea level change. Tectonic movements are tracked by GPS and satellite altimetry. Ocean heat data is used to calculate the contribution of thermal expansion. Changes in the gravity field as measured by satellites tell us how much mass is being added to the oceans. All these factors indicate thermal expansion and melting ice sheets contribute almost all of sea level rise.
  4. Don't be too quick to make an assumption that corals will die off. Connolly, Sean R., and Andrew H. Baird. 2010 try to demonstrate that corals might have the ability to migrate to cooler waters. This makes perfect sense if we consider that at the end of the last ice age that global sea levels rose by some 300-400 ft. Some of the inputs at the termination of the last ice age consisted of rather huge amounts of fresh water, such as the draining of Lake Agassiz. If these events were that huge then one must consider that corals (shallow and deep water) might have the ability to adapt.

    The reason there is a perception that sea levels around Scandinavia are lowering is due to crustal uplift, a result of GIA (glacial isostatic adjustment), which is a process that is still ongoing as a result of the end of the previous glaciation..
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  5. In an article entitled Tuvalu - the touchstone of global warming and rising sea level, Professor Cliff Ollier (UWA) makes claims almost identical to those made by Monckton but goes a step further by claiming that sea levels are actually declining.

    Both ignore the effects of melting polar ice sheets and glaciers. Ollier even asserts that in the case of the Greenland ice sheet, melting is so slow as to have little or no effect on sea level. Rob Painting shows in this article shows that both are wrong.

    Melting of the Greenland and West Anatarctic ice sheet (WAIS) have the capacity to raise sea levels by 13-18m. Greenland is expected to reach a tipping point within the next 30 years, and WAIS, a marine ice sheet, under attack from a warming southern ocean has potential to break-up causing more rapid rise in sea level.

    That sea level has been rising and continues to rise at an accelerating rate is yet another empirical measure which Monckton and Ollier ignore. But hey! Why let facts stand in the way of a reassuring story which falsely tells us we have nothing to worry about?
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  6. I don't know why, but every time I see a picture of the dear Lord, the first thing that comes to mind is -- Monty Python. And then when he opens his mouth and begins to speak, it reminds me of that movie that starred Jim Carey and Jeff Daniels.
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  7. Ron Crouch @6, perhaps you had in mind a sporting event?
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  8. Every time I see the usual zombie posting by "skeptics" who haven't done their homework I'm reminded of this MP bit:

    Not a fair fight, as they don't even realize they've lost the debate before they started...

    (apologies for being O/T...and yes, I should know better)

    The Yooper
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  9. Living proof that even here at SkS there is room for a little comic relief, but wasn't that the GOP Caucus Tom?
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  10. Ron Crouch @4, Corals will almost certainly not die of as a result of Global Warming. They are a diverse and reasonably robust class of animal, and it would be astonishing if all examples were driven to extinction. On the other hand, most or all of currently existing reefs are likely to be destroyed, or significantly altered by Global Warming, with surviving corals likely to form new reefs at higher latitudes than currently exist. Although smaller corals are coping better with warming, and multiplying in number, I do not think they good at building reefs, ie, with coping with sea level rise.

    Further, on BAU scenarios, it is likely that a large number of coral species will go extinct. That is an inevitable consequence of stressed conditions with limitted number of refuges. It should be born in mind that the currently dominant corals supplanted to previously dominant types at the time of the Permian extinction, and that corals have not always been the dominant reef building organisms on Earth. If GMT rises towards the 10 degree mark in the space of a couple of hundred years, there is no guarantee that corals will continue being the dominant reef builders in the future.
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  11. Daniel,

    I just love that skit. I saw it a while ago, except on that occasion it was making fun of the GCR argument.
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  12. Thanks for elaborating Tom. I'm not going to say that some coral species might not go extinct, some might, but in the long term I don't see all coral species disappearing either. Even since the end of the Permian coral species have managed to weather many storms (glacials/interglacials, Chicxalub, etc). I agree that 10oC more may be stretching the limits that corals can tolerate, and then there's also the question of pH tolerance. As far as the role that corals might play in the future, I would prefer not to speculate.

    If we compare the temperature record here with the extinction intensity here it would tend to indicate that we're not currently to badly off (yet) in comparison to Earth's historical past, but then the Earth's population wasn't pushing 7 billion either, and that presents a whole new wrinkle.

    The bottom line being that it's not too late to avoid dangerous climate change, but it will take a massive commitment on the part of all this planets inhabitants to avoid it.
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  13. As someone who lives on the coast, I have a question regarding sea level rise:

    If sea level is rising, say 2mm per year, is that a uniform rise throughout the tide cycle or is it nonuniform? For instance, would I simply add 2mm to the lowest tide level, the mid-tide level and the highest tide of the day or would it be nonuniform with the average equaling 2mm? If it is the latter, would that mean that I should add something more than 2mm to the high tide level?

    Thanks in advance for any enlightenment!
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  14. Tom Curtis & Ron Crouch - 4 of the 5 major extinction events lead to the complete disappearance of coral, for many millions of years at a time. The current rate of ocean acidification is unprecedented, outside of an asteroid impact. I wouldn't bet against them being eliminated altogether, but I certainly hope not!.

    Everett - click on the link provided with figure 1. Whole lot of information there from an authority on the topic. The 3mm SLR is a global average. It can vary from place to place for a number of reasons (see CMAR CSIRO link), but no, it's not simply a matter of adding 3mm to each phase of the tide.
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  15. Everett Rowdy @13, that is an even rise of all tide levels, but first not all tide levels will be the same on a local basis because the effects of change in barometric pressures and onshore of of shore breezes. A high pressure system, for example will lower tide levesls, while a low pressure system will raise them. Consequently a 2mm or even a 2 cm rise in SL will probably not be detectable as a straightforward rise, but rather as an average effect.

    More importantly, many parts of the world are either rising or sinking due to the motion of the continental plates. Much of south east asia is rising, for example, because of the slow northerly advance of the Australian continental plate. Further, some parts of the world are still rebounding from the loss of mass resulting from the melting of ice sheets at the end of the last glacial. That is true of scandinavian countries, for example. These motions are generally significantly larger than current changes in sea level. The effect of Mean Sea Level rise in those areas will be to make the areas that are sinking to have a more rapid sea level rise; and the areas that are rising to have a slower sea level fall. So absent more information, I cannot tell you whether the relative sea level on your section of the coast is rising or falling.
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  16. Rob Painting @14, very interesting. I knew it had happened at the Permian extinction event, but not in so many extinction events. By disappear, you of course mean disappear from the fossil record, and artifact of a limited number of survivors in remote refuges.

    I would be surprised by the complete extinction of all corals. This is not because I do not think the stresses are sufficient. With global warming causing coral bleaching, ocean acidification, increased sedimentation due to greater river run offs, and increased storm damage - not to mention dynamiting of reefs as a fishing technique (as is done in Indonesia) and the stresses of ecosystem collapse; there are certainly likely to be enough stresses to cause it.

    However, the manner of coral dispersal implicit in their reproductive cycle suggests that if there are any suitable refuges for corals in the world (almost inevitable given the worlds size and complexity), some corals will find their way to those refuges. Of course, even so, it will be many thousands of years before corals would again be able to become major reef builders in BAU scenarios.
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  17. Addendum to @16, corals have definitely survived through oceans at least as acid as those expected as a result of BAU by the end of this century, ie, with CO2 contents as high as is expected by then. That does not mean current living species of coral can do so without stress, for they will have adapted to the low CO2 levels over the last 50 million years. Ocean acidification will be another stress on corals.
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  18. Just a comment to the Mörner-paragraph: Niklas is a perfectly valid first name in Sweden, but his real name is Nils-Axel Mörner.
    I also wonder in what way it is relevant, in respect to his authority on sea level matters, that he has "dabbled in dowsing". Dowsing is certainly humbug, but would it also have been mentioned that Vermeer and Rahmsorf both are ardent astrologists, if that had been true? I doubt it.
    The purpose is solely to lessen his credibility. What is the term? Guilt by association?
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    Response: [John Cook] Apologies to Rob Painting but I have removed the reference to dowsing in the article. The reference is ad hominem which is not appropriate at Skeptical Science, nor is it required. All that's needed is to examine the scientific veracity of Axel-Morner. His claim that "it is physically impossible for sea level to rise at much above its present rate" clearly contradicts many lines of evidence.
  19. Anthony - The purpose is solely to lessen his credibility

    If you actually read some of Axel-Morner's claims, you will find he has done far more damage to his own credibility than I possibly could.
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  20. Tom Curtis - I understand what you mean about the coral dispersal. It's why some have dubbed them the "cockroaches of the sea". And yes, earlier generations of coral became extinct. New species evolved to re-colonize the oceans millions of years later. See Mass extinctions and ocean acidification - Veron 2008

    These "reef gaps" in the geological record indicate we may not be understanding the whole picture. Warming oceans are causing more frequent and severe bleaching events, but they also stratify the oceans, which will impact coral through the reduction in nutrient upwelling (very important in many lower latitude reefs where the elevated nutrient load helps to offset lower ocean pH). Coral do after all live in a "marine desert".

    Some recent work suggests that some coral are literally "swimming for their lives" to escape too warm waters Coral marches to the poles. But escaping to cooler waters is only a temporary respite because they will acidify more quickly.

    As far as where we're headed - it's the speed of change that is the killer, for acidification it means the natural calcium carbonate buffering process can't keep up (it operates on millenial timescales to lower pH) and the upper ocean will greatly acidify. Now I'm relying on recollection here, but I seem to remember reading a paper where they estimated ocean pH expected later this century has not occurred for 8 million years?. Might have that wrong, but certainly lower pH than existed during the Pliocene (2-5 million yrs ago). Conditions the current generation of coral have not experienced. Which is of course another matter, modern day coral are composed of aragonite, which is more soluble than the calcite skeletons of ancient coral.

    There should be a couple of more "coral" posts in the next couple of weeks. But the overall picture is that it's not a happy time to be a coral scientist, that's for sure.
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  21. Anthony Warming post #18

    "I also wonder in what way it is relevant, in respect to his authority on sea level matters, that he has dabbled in dowsing"

    Would you hire someone to a position of authority in a scientific field who believes in dowsing? Surely it says something about that person's scientific thinking - or lack of it - that he believes in dowsing.

    "Dowsing is certainly humbug, but would it also have been mentioned that Vermeer and Rahmsorf both are ardent astrologists, if that had been true?"


    "The purpose is solely to lessen his credibility. What is the term? Guilt by association?"

    Poisoning the well.
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  22. Rob Painting @20, speed of change is definitely the kicker here. A similar change over 10 thousand years would be nothing much to worry about, ecologically speaking. But compressed into one or two centuries ...

    These are probably very interesting times to be a coral scientist. They are no doubt learning new things very fast at the moment, at the same time that they risk being left without a subject matter.
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  23. Anthony G. Warming wrote : "Dowsing is certainly humbug, but would it also have been mentioned that Vermeer and Rahmsorf both are ardent astrologists, if that had been true? I doubt it.
    The purpose is solely to lessen his credibility. What is the term? Guilt by association?"

    If Vermeer and Rahmsorf were ardent astrologists I would certainly want to know about it and would certainly view them in a different light. Who wouldn't ? Who wouldn't also have doubts about scientists who believe that Creationism is a better explanation than Evolution ?

    And Morner's credibility is adequately lessened by his blind faith in his own abilities over and above the vast majority of scientists currently working in the field he is retired from.
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  24. @16 It's possible that few corals species survive an extinction event in isolated places. But iirc Charlie Veron noted in his Royal Society presentation that the species found after an extinction are completely different/new.

    @17 Different evolutions of coral during different environments are therefore more or less susceptible of ocean acidification. The species that have evolved since the last extinction never experienced acidification levels expected this century. (Again, iirc re Veron's presentation. It's been a while since I watched it.)
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  25. Talking about rise in sea level, I don't know if any of you has come across this paper about the Greenland ice sheet which was recently published in "Nature".
    The gist of it is that contrary to expectations, hot summer temperatures may actually slow down the flow of glaciers towards the sea, as the melting causes the internal drainage system to adapt to the warmer temperatures. I don't know whether the slowing down effect has been modelised or quantified, but apparently, the same thing had been previously noticed about mountain glaciers.
    The "news" was broken on ABC radio at 5 pm with the message that we should not be worried too much about climate change since the Greenland ice cap is not really melting then sea levels will not rise !
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  26. Phil263
    the last sentence of the Dailymail article reads:
    "Despite their findings, however, the researchers were keen to emphasise that the ice sheet is 'not safe from climate change'"

    Anyway, Daniel Bailey did a much better job than the Dailymail.
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  27. Clearly, regardless of ones position on AGW, there is evidence of average mean sea level rises going back a long way. Clearly some is directly related to natural processes and clearly some is directly related to the reduction in ice cover of the Northern Ocean, and glacial melt.

    As has been pointed out, there is a combination of factors at play that alter the localised picture due to forces that are clearly beyond human control, and likely always will be. It is a very difficult matter I think to truly attribute a given percentage to melt at this time because, sadly, the accuracy and the data sets are not there as all the articles do not differentiate between natural and perceived AGW causes of the rises, and this is important if the "human" factor is to be proven to the point of silencing any doubt.

    One thing I am curious about, and sorry if this sounds really harsh, but has anyone actually looked at the amount of land lost against the amount of land gained? If global air and sea temps rise as much as is predicted by 2100, then about 8 times as much land will be available for human use as will be lost to the sea. Clearly some of this land will be useless for sometime, but a lot, such as the vast wildernesses of Siberia and northern Canada will be usable.

    Now before I get seriously flamed for that comment, I would like to simply point out that regardless of what action man takes, if nature does not respond or we are wrong and many aspects are natural or simply under-estimated, then we still have a problem to deal with, one that is not going away and so we must face it head on. Putting sticking plasters on the broken leg may stop dirt getting into the wound, but it doesn't heal the broken leg..we must also look at long term solutions outside the box too.
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  28. Some more relevant graphs and info in this blog post:
    Past, current and future sea level rise

    I.e. also compared to the past thousands of years, it is blatantly obvious that sea level rise has accalerated in the past decades/century.
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  29. Cynicus @24, it is important to remember that "new" here just means new to the fossil record. The "new" species may just be former niche players that have taken advantage of relatively empty seas to expand to dominance. They may also be species evolved from previously dominant ancestors in refuges.

    In terms of human life spans, the difference is largely irrelevant. There will be no sudden recovery if the worlds major reefs are destroyed. In that event, we will face thousands, and maybe tens of thousands of years with out major living reefs, and hence with relatively barren tropical seas.
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  30. It pains me to write anything which agrees with Lord M, but doesn't the section of the article "...another study (Jevrejeva 2008) shows that the acceleration began as far back as the 18th century" raise some questions?

    What is the correlation between accelerating rises in sea level in the 18th century and anthropogenic warming? 'None' seems the only answer.

    Given that the data shows acceleration well before human activity could be having any impact, surely the scientific case needs to be made that the current acceleration rate is greater (or less) than it would otherwise be without human activity?

    What am I missing here?
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  31. LandyJim @27, it is fairly easy to make an approximate attribution for sea level rise. The vast majority of sea level rise is due to expansion of sea water due to increased water temperatures, and to glacial melt. As both of these correlate reasonably well with increase in Global Mean Temperature, the attribution of those factors can simply follow that of changes in GMT. That means humans are responsible for between 20 and 50% of sea level rise in the first part of the 20th century, and nearly all of it in the second half.

    Further, simply comparing land gained due to melting permafrost with land lost to sea level rise is simplistic. Any such comparison must also include land lost to basic cereals and other crops due to increased warmth. You should also include the marginal loss in the utility of land which has reduced frequency of harvests due to droughts, floods and other GW induced disasters.

    Considering all factors, for low temperature rises (up to 2 degrees C) there may (or may not) be a net gain; but for large temperature rises as projected for BAU at the end of the century, there is a significant net loss. For very large temperature rises such as may arise with BAU in 2 to 3 centuries, or in one if climate sensitivity is in the high end of the rain, as much as half of the Earth's surface will be seasonally uninhabitable for large mammals.

    Of course, none of that adresses questions of equity. Bangladesh can take no solace in the prospect of wealthy Siberian farmers.
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  32. mr duget @30

    First, most of the initial rise in sea levels is associated with the end of the Little Ice Age in the period from 1800 to 1850. There were natural causes for most of that, as also a significant part of the further warming in the early twentieth century. Of course,the identified natural causes for both those warmings have not been trending in favour of further warmth since about 1950, so that is no solace to any reasonable sceptic of global warming.

    Second, only most of that warming was natural. A significant portion of it was anthropogenic, a fact often forgotten. People often operate under the illusion that significant anthropogenic emmissions only began when coal started being burnt in steam engines (or boilers) in large amounts. But in fact, CO2 concentrations have been climbing for the last 8,000 years in large part due to deforestation, the expansion of rice paddies, and the expansion of cattle due to human farming techniques. From about 1600, anthropogenic emissions significantly accelerated due to the need for timber to build ships, and the use of coal for domestic heating. London was black from coal soot by about 1600 AD, and England denuded of forests (except the King's hunting forests) within a century of that from the demand for timber for ships.

    The emmissions of that period pale into insignificance compared to modern emmissions, but were still large enough to already be influencing climate. The difference in modern times is that anthropogenic emissions have changed from an influence, to the main driver of long term trends.
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  33. Thanks Tom. Interesting.

    Are you aware of any data that isolates the sea level rise/accelerations purely due to anthropogenic causes vs. natural causes? That would make the case clearer (for me at least).

    It is not really possible to interpret (anthropomorphically speaking) the graph of Global Mean Sea Level or Acceleration data without the natural contributions removed.
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  34. Tom Curtis - Pardon the question, but what is the origin of the "BAU" you have referred to? Is this an organization, a particular warming scenario, or what? Do you have links for it?

    Note to everyone - please expand the first use of your acronyms. Terms like "AO" and "TOA" may be perfectly comprehensible to someone used to such discussions, but if it's not explained somewhere we may prevent new-comers from understanding the threads.
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  35. Ah - reading through a couple more posts and recent comments, "BAU" is the "Business As Usual" scenario. I have seen that term before (but not the acronym); I just was not connecting it directly to coral discussion.
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  36. mr.duget, the last IPCC Report is always a good place to start for such questions. The link I give (via the red 'IPCC Report' text) is to 'Sea Level Variations Over the Last Glacial-Interglacial Cycle'.
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  37. Tom & Rob

    I agree that the speed at which change is taking place may be one defining factor in the survival of corals, and as we have discussed both temperature and pH also play important roles.

    It would appear though that some corals have the ability to produce a natural sunblock in the form of fluorescent pigments, and it is likely that these coral species stand a much better chance of survival than non-fluorescent species. We know the cure, it's the apathetic nature of politicians and the political process to implement change that is throwing a monkey wrench into the mix.
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  38. mr duget @33, according to the IPCC Assesment Report 4, between 1993 and 2003 thermal expansion caused Mean Seal Level to rise by 1.6 mm per year, melting of glaciers and ice caps caused it to rise 0.77 mm/yr, and melting of the Greenland and Antarctic ice sheets caused it to rise by 0.21 mm/yr each, for a total combined sea level rise due to the warming climate of 2.8 mm/yr of the 3.1 mm/yr observed. There is a small contribution to sea level rise from the drying lakes (such as the Aral Sea, and Lake Chad), depletion of ground water, which is partially compensated by the filling of artificial lakes. This may contribute to the 0.3 mm difference between prediction and observation; but that 0.3 mm is well within the margin of error, and so may not be significant.

    Durring that same period, net natural climate forcings were constant, or slightly declining. 1993 is sufficiently after any significant increase in natural forcings that we can ignore any lag effects. Therefore, 28 mm of the 31 mm rise in Mean Sea Level in that period is due to climate changes as a result of human activities, which is within margin of error of 100%.

    Prior to 1993 natural causes may have contributed some of the rise, and prior to 1950, it certainly contributed some of the rise. But is that really relevant given that our concern is about the future?
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  39. #25 Phil263

    Yes there is more on that here on the ESA site.
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  40. @29 Tom Curtis, I'm watching Charlie Veron's presentation again and he really says the corals went extinct during the Permian event (skip to slide 22):

    Every coral on this planet went extinct. No coral alive today lived during the Permian or lived through that extinction event.

    He then continues:

    And so we have a new group of corals evolving out of Actinia and that's the start of modern corals. And they are fairly different from their predecessors.

    Actinia are sponges, btw.

    So, trusting the expert on his word, during only this Permian event (not so for the other events) every coral literaly went extinct.
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  41. @37 "We know the cure, it's the apathetic nature of politicians and the political process to implement change that is throwing a monkey wrench into the mix."

    Let us not forget who owns those 'apathetic' politicians and that the real impediment to facing humanities AGW situation is
    a well organized, strategic corporate funded propaganda attack campaign based not on understanding new things science has to offer, but on demolishing anything threatening their business as usual.
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  42. Thanks, BillyJoe, 21!
    "Poisoning the well" certainly seems to be the term to use, when Mörner is first presented as having "extensively dabbled in dowsing". This sets the scene, sort of, so that we will know that nothing he says is worth listening to, (quote from Wiki):

    "A poisoned-well "argument" has the following form:
    1. Unfavorable information (be it true or false, relevant or irrelevant) about person A (the target) is presented by another. (e.g., "Before you listen to my opponent, may I remind you that he has been in jail.")
    2. Any claims person A then makes will be regarded as false, or taken less seriously."

    My point is that this is only done to a person you disagree with, and whom you want to discredit, as in the top post. You would not spread any such irrelevant information concerning those you trust.
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  43. I’m embarrassed to bring this up but I was disappointed in the last section of the initial post. The explanation seemed to side step the given quote:

    Monckton - "In the 11,400 years since the end of the last Ice Age, sea level has risen at an average of 4 feet/century, though it is now rising much more slowly because very nearly all of the land-based ice that is at low enough latitudes and altitudes to melt has long since gone."

    Sea levels have been rising 4feet/century... what?
    Even the implication that there has been steady significant rise occurring these past few thousand years seems questionable from my limited knowledge.
    ~ ~ ~ ~ ~ ~ ~


    . . . A fourth interval of rapid sea level rise 8200-7600 years ago was first identified by a hiatus in coral growth in the Caribbean about 7600 years ago {...}

    This spurt... apparently resulted from the catastrophic drainage of glacial Lakes Agassiz and Ojibway around 8400 yrs ago, releasing a volume of about 105 cubic kilometers within a few years or even less. But it only produced about 1 meter of global sea level rise, assuming an even spread of this volume spread across the world's oceans. Yet even this minor increase in sea level left an imprint in the stratigraphic record.
    By the mid-Holocene period, 6000-5000 years ago, glacial melting had essentially ceased, while ongoing adjustments of Earth's lithosphere due to removal of the ice sheets gradually decreased over time. {...}

    Over the past few thousand years, the rate of sea level rise remained fairly low, probably not exceeding a few tenths of a millimeter per year.{...}

    Since 1993, an even higher sea level trend of about 2.8 mm/yr has been measured from the TOPEX/POSEIDON satellite altimeter. Analysis of longer tide-gauge records (1870-2004) also suggests a possible late 20th century acceleration in global sea level.
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  44. Rob Painting - Regarding Mörner, I would have to agree with other posters that bringing up the dowsing smacks of poisoning the well, a form of argumentum ad hominem, and as such is inappropriate.

    Mörner makes enough errors in his climate-related science to be a poor source, but I think it would be more valid to leave his other (even the rather curious ones) interests out of the discussion.
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  45. This graph makes a good juxtoposition for Monckton's claim:

    "Past, current and future sea level rise"
    "What’s there to worry about sea level rise; it’s going very slowly, right? Let’s put current sea level rise in a historical perspective."
    From: Bart Verheggen’s weblog of climate change issues

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  46. Here's a probably unimportant question, but potentially interesting:
    How much water has/will evaporate (to become stored in the atmosphere) relative to the amount of sea level increase? Or, with a different focus, how much higher would sea level be if water vapour hadn't increased since 1970?
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  47. Steve L - I understand that the added 4% is roughly the volume of Lake Erie, or 484 km^3. Surface area of the oceans (skipping rivers and lakes) is ~3.61x10^8 km^2. Quick math (hope I have this right)

    484/(3.61x10^8) = 1.34x10^-6 km thickness

    or 1.34 millimeters drop in the oceans since 1970. That's less than half a single year's 3 mm rise.
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  48. Anthony @42 and KR @44, letting readers know that Morner has dabbled in dowsing seems to me more of a notice on Morner's well that he has poisoned it himself rather than actually poisoning the well. I would not ever cite as a scientific authority a young earth creationist, a dabbler in astrology, or a dabbler in dowsing. IMO that they are irrational in one area shows that their "rationality" in the area of their expertise is accidental - that they are not making mistakes (if indeed they are not) simply because they were taught which mistakes to avoid rather than because they are capable of correcting their misakes through rational analysis.

    I know that in the past, some giants of science have dabbled in pursuits now seen as irrational dead ends. Newton's interest in alchemy is the most famous example. The difference is that while Newton could draw on, there is no area of science that has now not been extensively elaborated. Belief in alchemy for Newton was based on inadequate information to demonstrate the error - belief in dowsing today is the deliberate choice of irrationality.

    Finally, Lord Monckton introduced Morner's claims by specifying that he was a professor with experience studying sea levels. He did not show the basis for those views, he merely apealed to authority. When an opponent argues by simple appeal to authority (and incosistently in that he is denying the more substantial authority of a large number of other experts in the field), it is certainly OK to impeach that authority. As Monckton's argument was no more than that this is a good well to drink from, pointing out that the owner of the well has poisoned it is no falacy.
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  49. KR @44 - As Tom Curtis points out Monckton's use of Morner was an appeal to authority.

    CC @ 43 - For the sake of brevity it's prudent not to address every single error. That's the beauty of the Gish Gallop. The essence of Monckton's claim was that sea level rise was much higher early in this interglacial period. Yes, we know that.

    CC @ 45 - The scale of that graph makes it difficult to discern, but sea levels were higher mid-Holocene. As for juxtaposition, well a matter of interpretation I guess. To the average lurker that seems to justify Monckton's claim that sea level rise was faster earlier in the Holocene. Yes, we know that!.
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  50. Rob Painting@49 FWIW I agree with KR, even if Monckton's use of Morner was an appeal to authority, that doesn't justify the use of rhetorical devices in a scientific discussion. Better to keep the high ground.
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