Stefan Rahmstorf and the consensus of experts on sea level -vs- reality, reality wins

From Stefan Rahmstorf and the Potsdam Institute for Climate Impact Research (PIK)

Expert assessment: Sea-level rise could exceed 1 meter in this century

In contrast, for a scenario with strong emissions reductions, experts expect a sea-level rise of 40-60 centimeters by 2100 and 60-100 centimeters by 2300. The survey was conducted by a team of scientists from the USA and Germany.

“While the results for the scenario with climate mitigation suggest a good chance of limiting future sea-level rise to one meter, the high emissions scenario would threaten the survival of some coastal cities and low-lying islands,” says Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research. “From a risk management perspective, projections of future sea-level rise are of major importance for coastal planning, and for weighing options of different levels of ambition in reducing greenhouse-gas emissions.”

Projecting sea-level rise, however, comes with large uncertainties, since the physical processes causing the rise are complex. They include the expansion of ocean water as it warms, the melting of mountain glaciers and ice caps and of the two large ice sheets in Greenland and Antarctica, and the pumping of ground water for irrigation purposes. Different modeling approaches yield widely differing answers. The recently published IPCC report had to revise its projections upwards by about 60 percent compared to the previous report published in 2007, and other assessments of sea-level rise compiled by groups of scientists resulted in even higher projections. The observed sea-level rise as measured by satellites over the past two decades has exceeded earlier expectations.

Largest elicitation on sea-level rise ever: 90 key experts from 18 countries

“It this therefore useful to know what the larger community of sea-level experts thinks, and we make this transparent to the public,” says lead author Benjamin Horton from the Institute of Marine and Coastal Sciences at Rutgers University in New Jersey. “We report the largest elicitation on future sea-level rise conducted from ninety objectively selected experts from 18 countries.” The experts were identified from peer-reviewed literature published since 2007 using the publication database ‘Web of Science’ of Thomson Reuters, an online scientific indexing service, to make sure they are all active researchers in this area. 90 international experts, all of whom published at least six peer-reviewed papers on the topic of sea-level during the past 5 years, provided their probabilistic assessment.

The survey finds most experts expecting a higher rise than the latest IPCC projections of 28-98 centimeters by the year 2100. Two thirds (65%) of the respondents gave a higher value than the IPCC for the upper end of this range, confirming that IPCC reports tend to be conservative in their assessment.

The experts were also asked for a “high-end” estimate below which they expect sea-level to stay with 95 percent certainty until the year 2100. This high-end value is relevant for coastal planning. For unmitigated emissions, half of the experts (51%) gave 1.5 meters or more and a quarter (27%) 2 meters or more. The high-end value in the year 2300 was given as 4.0 meters or higher by the majority of experts (58%).

While we tend to look at projections with a focus on the relatively short period until 2100, sea-level rise will obviously not stop at that date. “Overall, the results for 2300 by the expert survey as well as the IPCC illustrate the risk that temperature increases from unmitigated emissions could commit coastal populations to a long-term, multi-meter sea-level rise,” says Rahmstorf. “They do, however, illustrate also the potential for escaping such large sea-level rise through substantial reductions of emissions.”

###

Article: B. P. Horton, S. Rahmstorf, S. E. Engelhart, A.C.Kemp: Expert assessment of sea-level rise by AD 2100 and AD 2300. Quaternary Science Reviews (2013). [doi: 10.1016/j.quascirev.2013.11.002]

Link to the article when it goes online: http://dx.doi.org/10.1016/j.quascirev.2013.11.002

============================================================

The basic premise of Stefan Rahmstorf’s claim is that sea level rise will accelerate before the end of the century. So far there has been no evidence of acceleration, it appears entirely linear no matter whether we look at tide gauges or satellite measurements.

The image below (From Holgate 2007 On the decadal rates of sea level change during the twentieth century in GRL) shows Holgate’s reconstruction of the sea level rise rate for the 20th century from the highest quality tide gauge data.

holgate-9-station-with-std-dev-digitized[1]

As you can see, the sea level rise rate widely varied during the 20th century.  It reached about 4 mm/year around 1911, and again in the 1930s, 1950s and around 1980.   It was much lower in the 1920s, 1940s, 1960s and mid-1980s.

Holgate concludes:

Based on a selection of nine long, high quality tide gauge records, the mean rate of sea level rise over the period 1904–2003wasfoundtobe1.74±0.16mm/yr after correction for GIA using the ICE-4G model [Peltier, 2001] and for inverse barometer effects using HadSLP2 [Allan and Ansell, 2006]. The mean rate of rise was greater in the first half of this period than the latter half, though the difference in rates was not found to be significant. The useof a reduced number of high quality sea level records was found to be as suitable in this type of analysis as using a larger number of regionally averaged gauges.

For satellite measurements there also doesn’t seem to be any acceleration.

German veteran meteorologist Klaus-Eckart Puls has done an analysis of sea level rise. Contrary to many claims, we see that sea level rise has decelerated markedly since 2003.

Puls_2[1]

- See more at: http://notrickszone.com/2012/12/06/meteorologist-klaus-eckart-puls-sea-level-rise-has-slowed-34-over-the-last-decade/#sthash.h1npSYgJ.dpuf

So, neither tide gauges nor satellite measurements suggest acceleration is occurring. Even if we use the worst case value, 3.2 mm/year cited by CU in a linear calculation…

…we get this:

years left 2100-2013= 87 years

3.2 mm/year * 87 years = 278.4mm  or 0.2784meter…about a quarter of the 1 meter (or more) claim made by Rahmstorf.

Rahmstorf isn’t working in reality.

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92 thoughts on “Stefan Rahmstorf and the consensus of experts on sea level -vs- reality, reality wins

  1. Whatever anyone says these creatures will not deviate from their message. Bad monkey. If you keep burning stuff you will drown. (after I am tenured/retired/dead)

  2. … according to the first paragraph, Rahmstorf is suggesting 40 – 60 cm. by 2100, not a meter, as alluded to in your final paragraph.

    For the record.

  3. The linear fixation is based on either a belief in or a refutation of the linear effect of rising CO2 concentrations. That is the falicy that needs to be beaten down. All fall from that.

  4. A friend of mine defined “expert” this way: A drip under pressure. And these so-called experts are under pressure to make themselves look right, regardless of the facts.

  5. If they’re picking numbers under-which they’re at 95% confident the sea level rise would stay, sounds like high numbers are looking good ;-)

    If someone asked me what I’m 95% confident the December-January high temperature in Chicago will stay under, 100°F sounds like a good number… 200° would also work ;-)

    Now, if they were asked for a number above-which they were 95% sure the sea level rise would exceed… I bet we’d see a much different picture.

  6. if the actual issue is sea level (where the water comes up to on land) then the GIA correction needs to be removed. with the addition of the GIA correction, it seems that they are more interested in sea volume than sea level

  7. “While we tend to look at projections with a focus on the relatively short period until 2100, sea-level rise will obviously not stop at that date.”

    Do we really know with any certainty that it will not stop at that date? It has to stop at some point. I guess the word “obviously” is meant to squelch that question.

  8. Germans dilute EU auto emissions standards, the new EU tighter standard is the only reason BMW, Porsche and Mercedes are producing loss making electric vehicles, nail in electric coffin.

    Seems Merkal is more concerned in supporting the German car industry than sea level rise.

  9. OT: Climate Scientists and Lawyers… And SuperMandia

    http://www.straight.com/news/535376/climate-scientists-get-lawyered

    “The American Geophysical Union, representing more than 62,000 Earth, atmospheric, and space scientists worldwide, has teamed with the Climate Science Legal Defense Fund to make lawyers available for confidential sessions with scientists at its annual meeting next month.”
    And
    “It’s an issue few researchers contemplate as they prepare for a career in science, said Scott Mandia, professor of physical sciences at Suffolk County Community College in New York and founder of the Climate Science Legal Defense Fund.”
    ==
    When science does not suffice… get a lawyer! LOL

  10. Is there a quantified breakdown into the magnitude of the different components that make up the predicted one meter rise. eg thermal expansion, melting glaciers, melting Greenland, melting Antarctic, what else? Which are the big contributors? It would then be interesting to look at the evolution of the history of each component so that necessary changes in rate can be pinned down and the underlying expected components more deeply examined as too root cause of change.

    It will be far more interesting than holding a poll.

  11. “The experts were also asked for a “high-end” estimate below which they expect sea-level to stay with 95 percent certainty until the year 2100.”

    Nothing like making sure you get the high value you are wanting to appear.

  12. I’m not normally one to comment here, but looking at the “worst case”…

    In just under 300 years, sea levels *may* have risen by 1m. In 3 centuries – 1m. If I were still alive, if I’d stood still at the high water line, my groin would now be underwater – and I’m not very tall.

    We’ve put a man on the moon. We’ve got a 30 year old space probe at the heliopause, at the edge of our solar system. We’ve got telescopes in space that can analyzer the atmospheres on planets hundreds of light years away. There is a nuclear powered partially autonomous robot tank trundling around another planet FGS.

    And they’re worrying about a 1m rise in sea level.

    What are we? Men or Mice? Our forebears colonised a hostile world, and some of us are losing sleep over the fact that in 3 centuries, the sea may be very slightly higher than it is now.

    Adapt or die people.

  13. “Overall, the results for 2300 by the expert survey as well as the IPCC illustrate the risk that temperature increases from unmitigated emissions could commit coastal populations to a long-term, multi-meter sea-level rise,” says Rahmstorf”

    Projecting out to the year 2100 has an extreme amount of uncertainty. Going to 2300 is totally absurd. The world will have run out of fossil fuels to burn centuries earlier. There will either be a new source(s) to replace it or humans will have long since run out cheap energy and the rapidly diminishing supplies cost multiple times what we pay now and only the rich can afford, the small amounts left. This should play out well before the end of this century.

    The “results for 2300″ and “expert survey” are a contradiction. No authentic expert (knowledgeable of factors mentioned above) in this field would project to the year 2300. This is 200 years beyond outlandish.

  14. Professional – a person who earns a living doing something, who sometimes makes a mistake but who learns from it, picks up the pieces and carries on a wiser person.
    Expert – a person from the next-but-one city with a suit and a laptop.

  15. “Expert assessment: Sea-level rise could exceed 1 meter in this century”
    Common sense assessment: SLR, which has been rising at about 6″ per century for centuries will probably continue to do so, or even decline slightly due to expected cooling.

  16. Henry Galt says:
    November 22, 2013 at 8:17 am
    Whatever anyone says these creatures will not deviate from their message. Bad monkey. If you keep burning stuff you will drown. (after I am tenured/retired/dead)
    ———————————————————–

    The pseudoscience is settled.

  17. Sea Level! And so, since there is nothing we could do about it, even were it true, and even were it due to activities of people ( which it is not) as opposed to naturally occuring events, and since China and India are not going to change their ways, WTF? Most of us do not live on the coast, in any event, and the costs of even trying to change it in terms of human suffering are probably greater than any potential benefits, assuming one could do anything about it. Forgetaboutit.

  18. Stefan Rahmstorf has a conflict of interest, that might account for his disagreements with reality. He’s bankrolled by Munich Re, the giant German reinsurance company, and his scaremongering is money in the bank to them, because they can use it to justify higher reinsurance rates.

    “It turns out that Rahmstorf has pulled an elaborate practical joke on the Community…”
    - Steve McIntyre

    More on Rahmstorf here: http://tinyurl.com/rahmstuff

    More on sea level here: http://www.sealevel.info/

  19. Pete Smith;
    We’ve put a man on the moon. We’ve got a 30 year old space probe at the heliopause, at the edge of our solar system. We’ve got telescopes in space that can analyzer the atmospheres on planets hundreds of light years away. There is a nuclear powered partially autonomous robot tank trundling around another planet FGS.
    >>>>>>>>>>>>>>>>>

    Repeated for effect.

  20. TomRude says:
    November 22, 2013 at 8:58 am

    “It’s an issue few researchers contemplate as they prepare for a career in science, said Scott Mandia, professor of physical sciences at Suffolk County Community College in New York and founder of the Climate Science Legal Defense Fund.”

    Hack professor at Podunk Community College? It’s mildly amusing that this putz thinks he has a “career in science”

  21. Pete Smith says:
    November 22, 2013 at 9:14 am

    Thanks Pete – very well put. Adapt or die…….our ancestors did. Why are we such timid creatures all of a sudden?

  22. Ace-” according to the first paragraph, Rahmstorf is suggesting 40 – 60 cm. by 2100, not a meter, as alluded to in your final paragraph. For the record.”

    For the record, Rahmstorf chose the title of his article, which comes prior to the first paragraph, and it says “Expert assessment: Sea-level rise could exceed one meter in this century”

    And maybe you missed this part-(in bold for you) “In contrast, FOR A SCENARIO WITH STRONG EMISSIONS REDUCTIONS…experts expect a sea-level rise of 40-60 centimeters by 2100 and 60-100 centimeters by 2300. The survey was conducted by a team of scientists from the USA and Germany.”

    Not sure why Anthony chose not to include the whole introduction in the Postdam article in his review of it, as it would make things more clear, but it’s below:

    “11/22/2013 – Sea-level rise in this century is likely to be 70-120 centimeters by 2100 if greenhouse-gas emissions are not mitigated, a broad assessment of the most active scientific publishers on that topic has revealed. The 90 experts participating in the survey anticipate a median sea-level rise of 200-300 centimeters by the year 2300 for a scenario with unmitigated emissions. In contrast, for a scenario with strong emissions reductions, experts expect a sea-level rise of 40-60 centimeters by 2100 and 60-100 centimeters by 2300. The survey was conducted by a team of scientists from the USA and Germany.”

    So indeed, Rahmstorf DOES suggest a 1m+ rise if emissions are not mitigated. The 40-60 cm rise is expected if there IS some “strong emissions reductions”.

  23. The “high-end estimate below which they expect sea-level to stay with 95 percent certainty until the year 2100″ translates to “they are 95% sure sea level rise will be LESS than that.”
    It makes no sense to worry about the sea level in 2300 before 2200 at the earliest; that will still be beyond the lifetime of anybody able to think rationally in 2200.

  24. A few months ago, RealClimate had a story with dire predictions of a huge rise in sea levels. I posted a comment, complete with a link to a paper from NOAA, pointing out that there is no evidence of recent acceleration in sea level rise, and that current trends do not support these dire predictions.

    I was denounced as a troll and prevented from commenting again.

    Surprizing given that I was not “denying” AGW or anyting like that. It was just a polite factually based post discussing a single technical point.

    This convinced me more than anything else could that RealClimate is not a scientific web site, but a church for true believers where even a hint of heresy is not tolerated.

  25. Protecting the world from sea level rise via control of CO2 emissions is only one way that the UN is trying to regulate energy use. Another is through the Stockholm Convention on Persistent Organic Pollutants. Using the arguably solid goal of limiting production of chemicals that persist in the environment, the Stockholm Convention is trying to control global warming. They argue that the precautionary principle must be applied and any chemical that might pose a risk be controlled. As DDT is already on their list of chemicals that need to be eliminated, their knowledge and logic needs to be questioned.
    The committee analyzing risk is called POPRC (Persistent Organic Pollutant Review Committee) called Pop Rock for short. They are not [now ?] drafting proposals to regulate chemicals based on how Climate Change will impact how chemicals are degraded in the environment.
    Latham&Watkins in there November Climate Report webinar showed these points:

    Establishes a procedure for considering climate change impact on POPs in all 3 phases that proceed a listing decision – i.e.,
    •(1) Proposal for listing by a Party;
    •(2) Evaluation by POPRC of proposal based on screening criteria; and
    •(3) Preparation of a “risk profile” if POPRC decides listing is warranted
    •Impact refers to:
    •Impact of climate change on intrinsic properties of a chemical
    •E.g., Climate induced effects, such as increased precipitation, permafrost thawing and reduced ice and snow cover lead to increased revolatilization of chemical and longer range transport as a result
    •Impact of the chemical due to climate change
    •E.g., Chemical more toxic to aquatic life in warmer ocean temperatures

    Essentially all of the reasons for including climate change in the analysis of the potential impacts of POPs is speculation, and perhaps wild speculation at best. But this treaty will probably be used as a second reason for controlling GHG emissions from fossil fuels.
    Here is an example from the L&W presentation on their logic:
    There are various technological measures presented within BAT and BEP lists which are directed towards improvement of combustion conditions, energy efficiency, energy recovery rates, and emission reductions (EEA, 2006; Nemet et al., 2010). These measures are designed for application in various industrial sectors and the transportation sector where both GHGs and unintentionally produced POPs can be released to the atmosphere. The following sectors are of particular importance in this context: combustion of fuels in utility burners for electricity and heat production, industrial and residential boilers (particularly those fuelled with wood and other biomass), waste incinerators, crematories, cement kilns, primary and secondary non-ferrous metal industries, pulp production, specific chemical production and motor fuel firing. The choice of specific technology would have a direct impact on releases of GHGs and unintentionally produced POPs.
    Draft Guidance, p. 40

    This connection between a potentially good regulation driven be a AGW agenda is frightening. Will all issues ultimately be usurped by AGW with claims that global warming will change everything and we need to act now to prevent it?

  26. The warmist alarmists use projections as scare tactics, like the result of what rising sea levels will be or could mean. They are like a lion roaring at you from a close distance, but when you look into the lion’s mouth, it has no teeth. Regardless, the lion’s roar will scare you, and some even into a panic mode.

  27. Why do they stop at the year 2300? If we go far enough into the future with their 1st-grader straight line reasoning, we will have global inundation. Is that what Noah, I mean NOAA wants?

  28. Judging by this article, I am now writing a presentation on Sea Level Rise, and what it might be. Hmmm. I believe it will be less than 10 meters by the year 2100 and certainly more than 10 mm. I am sure this is going to be reviewed by my peers here, possibly egged, for all I know, but reviewed and published. If I do this 6 or 7 times, will that make me a peer reviewed, published expert on Sea Level Rise? Can I then join in with the 95% concensus and where do I sign up for a grant? In this economy, I can use all the [financial] help I can get.

  29. What if the whole idea that CO2 will heat the Earth up is WRONG? Oh we never thought of that because we know that isn’t true. What happens to ocean levels when the Earth cools? Uhhh …..

    As much as I hope Dr Libby was wrong I’m thinking it will take another ice age to get rid of these ID10T types.

  30. Sigmund Freud once said that sometimes a cigar is just a cigar. May we concede, however, that sometimes a cigar is not, and this statement by Stefan Rahmstorf certainly seems to reveal the real hidden meaning behind much of climate science: “… and for weighing options of different levels of ambition in reducing greenhouse-gas emissions.”

    Notice one word that stands out, “ambition”. Who are our global warming mavens? John Kerry (5 mansions)? Barack Obama (Hollywood fundraisers; golf with Tiger Woods)? James Hansen (250K check from Theresa Kerry)? Maurice Strong (1 million dollar check from Saddam Hussein’s regime)? Oh, and let us not forget long time presidential wannabe, multiple mansion owning, private jet commuting, multi millionaire Al Gore. Do those names define the word, ambition?

    For what other possible reason would taxpayer funds be influenced by these people to go into research to predict sea level rise in the year 2100 or 2300? Perhaps in the year 1700 the monarch, His Excellency Hubrismandia, should have set in place policy to affect us in the here and now.

  31. The fact of the matter is that there aren’t 90 persons in the world who are truly expert on the complexities of sea-level variations. But that becomes immaterial when the myopic standard of recently published papers is used as the criterion of expertise. It flies in the self-indulgent, make-believe world of academia.

  32. Data at Colorado University’s Sea level Research Group in 2004 said sea level was going up at 2.6 mm/yr. You can verify that using the Internet Archive’s WayBack Machine. Today that same time series 1992 – 2004 says it was going up over 3.5 mm/yr. An adjustment/correction of around 0.9 mm/yr.

    Since 2004, today’s data at the CU website says sea level is going up 2.8 mm.yr these last ten years. Remove the 0.9 mm/yr adjustment and it’s only 1.9 mm/yr.

    So, 60 cm by 2100? That requires 7 mm/yr starting right now. The current rate would have to more than triple this afternoon in order for that to happen. One meter by 2100? Ha ha ha ha ha!

  33. The propagandists are doing their fear-mongering with the deliberate intent of inducing panic.

    A physician friend (he’s not ordinarily this gullible; he did, after all graduate from Harvard College) owns a second home located on a creek that’s a tributary of the Chesapeake Bay. He came home after a cruise on a ship through the Alaska Inner Passage where an eco-evangelist had given a lecture and was going to “fire sale” the property.

    When I pointed out to him that sea level rise has averaged 3mm per year ( about this much: __ ), he was chagrined and embarrassed. Needless to say, the facts were a revelation.

  34. Many years ago I participated in an expert elicitation. The elicitor managing the elicitation spent the first day going over the basis and explaining how things would be done. At the start of the second day, he had everyone write down their estimates for the range for one of the parameters we were evaluating, at the 90% confidence interval. After everyone did that, he reached into his shirt pocket and pulled out a $100 dollar bill. He then ask how many were willing to wager $1000 against his $100 that their estimated range of values encompassed the actual values that would be determined by site investigations (after all, the participants were 90% confident). About 10% of the group raised their hands and the rest wanted to revise their estimates. I often wonder if they still do this at elicitations.

  35. John W. Garrett @11:25 am

    I had a similar experience in Alaska about 7 years ago. I had no ammunition to argue back. On the way home I vowed that wouldn’t ever happen again. I’ve been obsessed ever since.

  36. The whole sea level rise bogey man is a bunch of B.S. There are hundreds of ports around the world with docking facilities, some of which have been in use for centuries. Who has ever heard of one of them being abandoned because of sea level rise?

  37. John says:
    November 22, 2013 at 8:29 am
    A friend of mine defined “expert” this way: A drip under pressure. And these so-called experts are under pressure to make themselves look right, regardless of the facts.
    ————————————————
    How about, “Anyone with a briefcase, more than 25 miles from home.”

    Neither def. is fair to the real climate “experts” who know when to say, “I don’t know”..

  38. I would like to share a very insightful essay of which I quote but a small part. If you substitute IPPC for Democrat and AR5 or Kiyoto or CAGW for Obamacare it takes on a broader meaning.
    I encourage you to read the whole thing at:
    Obamacare and the Systematic Denial of Reality

    http://onecosmos.blogspot.com/2013/11/obamacare-and-systematic-denial-of.html

    Some of the money lines:
    …” In this regard, it is very much like models of global warming, which work just fine in theory. Just don’t ask them to accurately model reality.
    Like those models of the climate, “Obamacare is a vast Rube Goldberg machine that, it turns out, doesn’t work at all — an airplane that has crashed on takeoff” .
    “One obvious lesson” — which liberals will never learn — “is that liberalism fails to appreciate the complexity of the world. The hubris required by the Democrats’ attempt to reorder not just a large sector of the economy, but an important part of the lives of millions [billions?] of strangers, is breathtaking”… [ to say nothing of the EPA or carbon taxation/trading schemes-RG]

    “So yes, it’s complicated. But not really; rather, it is complex, which is another thing entirely. Math is complicated, but it can be sorted out with patient application. But some things are irreducibly complex, such that rendering them merely complicated destroys them.”…

    …”Another critical lesson: “Obamacare also illustrates the inordinate faith that many liberals have in the power of words. Various aspects of reality are not as liberals would like them to be. What is the solution? The magical power of words: reams and reams of paper covered with sections and subsections, commands and requirements. If they can only get the words right, reality will certainly fall into line, just as liberals want it to be!”…

    …” Think about the basic contrast revealed in experience, “between the actualized happenings of the past” vs. “the possible or probable but not actual happenings of the future.” In short, “particulars are all past.” I mean, right? The past is what it is, and cannot be changed. Conversely, “there are no future particulars.” For which reason, “to think of the future is to think in more or less general terms.”
    “No one can predict the future, except in regard to extremely simple and linear systems that are easily abstracted and modeled.”…
    …”So they have their metaphysic precisely backassward: generalize the past and particularize the future. This is why, to paraphrase Orwell, “he who controls the past controls the future,” and why people living under communist tyranny would joke that “the future is known. It’s the past that keeps changing.”

    RTWT.
    -RG

  39. Are we back into hyping the skeer again? It seems we periodically have forecasts of catastrophic sea level rise, sometime in future decades where it can’t be evaluated and each one is worse than the next. It’s almost I see your 50 cm and raise you another 50. The forecasts for sea level disaster are so frequent and so different that I can’t remember all of them. It’s a joke.

    As for “adapt or die” I’m doing all the adapting I can but seriously doubt I’ll be adaptable enough to check out the 87 and 287 year predictions. I’m sure Rahmsdorf is counting on the fact that most of his audience won’t be that adaptable.

  40. Tangentially germane note:

    Rising sea levels are a GOOD thing.

    Please recall that at the LGM ~19,000 years ago, sea levels were at their all time lowest in geologic history. That is because a significant fraction of the world’s water was on land in the form of continental ice sheets.

    Since then much land ice has melted, but sea levels have yet to reach Tertiary norms.

    Should sea levels stop rising, it would be because ice is once again accumulating on land, signaling neoglaciation and the return of Ice Age stadial conditions. Indeed, that’s already happening on a multi-millenial scale.

    Which would be (indeed is) a BAD thing for humanity and Life in General.

    Warmer is better. Humanity has thrived while sea levels rise. So has terrestrial life, despite the marginal reduction in land area, because warmth renders formerly abiotic land biotic and vastly increases terrestrial (as well as marine) bioproductivity overall.

    Hooray for riding seas; be thankful. The alternative is not to be desired.

  41. Rahmstorf has a terrible track record when it comes to sea level rise modeling.

    See “Critique of “Global sea level linked to global temperature,” by Vermeer and Rahmstorf ”

    http://climatesanity.wordpress.com/critique-of-global-sea-level-linked-to-global-temperature-by-vermeer-and-rahmstor/

    and “Critique of “Testing the robustness of semi-empirical sea level projections,” by Rahmstorf, Perrette and Vermeer”

    http://climatesanity.wordpress.com/critique-of-testing-the-robustness-of-semi-empirical-sea-level-projections-by-rahmstorf-et-al/

  42. In a cross examination ask the experts for an estimate of sea level change which they expect to be exceeded along one in every twenty future history timelines until the year 2100. Then ask them how they intend to verify that proposition. That is, what state of affairs would make them accept it was false after all.

  43. Experts agree:
    Consequence for a far out projection of excessive sea level rise by 2100 for these experts:
    Nonexistent.
    Consequence for failing to make an alarmist projection:
    Career catastrophe.
    Number of experts opting for career catastrophe?
    None left on the payroll.

  44. Few if any of the buildings currently in existence will still be in existence in 200 to 300 years.
    Long before the seas take these buildings, they will have fallen down on their own from old age.
    The simple solution is to let these buildings age away, and then not replace them when they do.
    A no cost solution to rising tides and cities.

  45. What I fail to understand is what causes the rather large oscillation in the rate of sea level change. I mean it is a huge lump of water ( 1.3 billion cubic kilometers ) but its rate of change changes quite rapidly. Why?

  46. If these people could accurately predict the measurement of recession along with the degree of recession at different ages for the average climate scientists’ hairline then I just might accept their predictions for sea level rise and receding shorelines. Until then could they at least try to show a little consideration and stop bothering us with their schemes of self grandiosity.

  47. It all preys on the fact that people are too lazy to delve in to details-they just believe the headline propaganda flashed in front of their eyes. The upper limit is what was asked for and this is the headline propaganda they read, in spite of ALL the predictions thus far being wrong. Once people believe the incorrect fundamental assumptions, all that follows is predicated on very shaky foundations. When it all collapses in a massive heap, everything is crushed irreparably.
    The whole Fabian “Utopia” which is the excuse for all the BS is a model which will fail horrendously.
    Given that reality has been thus far at the very BOTTOM edge of the 95% curve, perhaps this is the one that should be on the headlines-it seems to be the closest.

  48. “The American Geophysical Union, representing more than 62,000 Earth, atmospheric, and space scientists worldwide”
    There are 62,000 of them? Why do we keep hearing only from the same few dozen of them? Don’t the other 61,900 have anything to say?

  49. Keitho says: November 22, 2013 at 12:09 pm

    What I fail to understand is what causes the rather large oscillation in the rate of sea level change.

    The short term changes of sea level rise are closely correlated to ENSO, see

    ENSO changes the fraction of total precipitation falling on land, which takes time to return to the oceans.

    The global sea level rise according to satellite data as interpreted by the University of Colorado Sea Level Research Group has declined from 3.23 mm/yr during 1993 – Dec 2003, to 2.46 mm/yr during Jan 2004 – Aug 2013, without GIA adjustment, as shown:

    The Pacific Ocean sea level rise has decelerated from 3.23 mm/yr to 1.72 mm/yr over the same time periods.

    However, the average of the 10 long tide gauge records on the Pacific coast of Canada shows that the sea level has DECLINED at 0.50 mm/yr from 1973 – 2011. These graphs are at:

    http://www.friendsofscience.org/index.php?id=712

    Note that sea level rise means the average sea level change with respect to the land. The GIA (glacial isostatic adjustment) is the effect of increasing ocean basin size. The graph of sea level rise by the University of Colorado in the lead post is sea level rise plus 0.3 mm/y GIA, which is NOT sea level rise. It is what the sea level rise might have been IF the ocean basin size had not changed.

    The satellite SLR is greater than the global tide gauge SLR because the University of Colorado adds a dubious 0.9 mm/yr adjustment to the raw satellite measurements, which they claim is due to sensor drift.

    • Thanks very much Ken. I am now off to look for a matching pattern between rainfall on land and the wobbles in the sea level record. With my newly learned statistical prowess and the diversity of data I may be gone for some time. :)

  50. Steve Case @ 11:29 am

    Thank god for WUWT and Mr. Watts, eh? It’s my “go to” source for information.

  51. Many moons ago I volunteered my diving services to archaeological teams working on the West Florida Coast. They were cataloging numerous ancient and inundated Indian villages. Florida was shaped over 6 to 7 millions years as is evidenced today by the geologic formations. Sea levels rise and sea levels fall but I’m having problems doing the maths when it comes to: primitive man x camp fires (+ planned and accidental brush burning) = CO2 output – ergo local flooding.

    http://ufdc.ufl.edu/UF00027829/00016/9j

  52. ace says: “… according to the first paragraph, Rahmstorf is suggesting 40 – 60 cm. by 2100, not a meter, as alluded to in your final paragraph.”

    Keep coming back, ace. Next time, please read the post and understand it before commenting. Or comment near the end of the thread, where you won’t attract as much embarrassing attention.

  53. Ok Willis, what does the wiggly line from Holgate 2007 correspond to? Sun spot cycles, the AMO, the PDO, the rate of CO2 release (oops, can’t be that one). Get to work!

  54. Still think this 1841 sea level benchmark on the `Isle of the Dead’, Tasmania by Antarctic explorer, Capt. Sir James Clark Ross is one of the greatest questions when it comes to a discussion of sea level. Why is this not showing the ½+ meter rise in the last 175 years? The mark should be underwater at low tide, and it is not. These charts are just more adjustements by dishonest “climatologists” to me, I know they are fudging it upward every year.

    (to see the scribed sea level mark clearly, thanks to the late John Daly)

  55. Every time I read one of these things I have to chuckle and shake my head. Apologies if I sound like a broken-record again, but what sort of climate should one expect, especially at a half-precession old, and at best 50:50 chance of being the most recent end interglacial?

    How is it, precisely, does anyone suggest we detect a one-meter sea level rise (anthropogenic signal) by 2300 if the lowest estimate of sea level rise during the second thermal pulse right at the end of the last interglacial was +6M amsl

    http://business.uow.edu.au/sydney-bschool/content/groups/public/@web/@sci/@eesc/documents/doc/uow045009.pdf

    and might have run up to +52M amsl http://lin.irk.ru/pdf/6696.pdf ?

    These are not unreasonable questions if you are familiar with the concept of signal to noise ratio (SNR) http://wattsupwiththat.com/2011/01/05/on-%E2%80%9Ctrap-speed-acc-and-the-snr/#more-30992

    So what are we to expect in terms of climate at an end extreme interglacial?

    Boettger, et al (Quaternary International 207 [2009] 137–144) abstract it (http://eg.igras.ru/files/f.2010.04.14.12.53.54..5.pdf):

    “In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai) is marked by at least two warming events as observed in geochemical data on the lake sediment profiles of Central (Gro¨bern, Neumark–Nord, Klinge) and of Eastern Europe (Ples). Results of palynological studies of all these sequences indicate simultaneously a strong increase of environmental oscillations during the very end of the Last Interglacial and the beginning of the Last Glaciation. This paper discusses possible correlations of these events between regions in Central and Eastern Europe. The pronounced climate and environment instability during the interglacial/glacial transition could be consistent with the assumption that it is about a natural phenomenon, characteristic for transitional stages. Taking into consideration that currently observed ‘‘human-induced’’ global warming coincides with the natural trend to cooling, the study of such transitional stages is important for understanding the underlying processes of the climate changes.”

    and:

    “In this respect, the Holocene shows a stable SST trend similar to those in previous interstadial stages, tending toward progressively cooler climate conditions in accordance with the slow decrease in summer insolation in the Northern Hemisphere and the minimal eccentricity of the Earth’s orbit. Within the framework of ODP-977A data, this orbital configuration suggests that the present warm period could be more prone to abrupt oscillations than MISs 5 and 7. In turn, the next bifurcation of the climate system may appear as an extremely intense cooling if the future natural climate is going to develop as an analog
    of some of the preceding warm periods.” http://home.sandiego.edu/~sgray/MARS350/pleist2.pdf

    As Anthony details in this article, we aren’t even close to experiencing “evident climatic and environmental instabilities”, not yet anyway. But given that “the present warm period could be more prone to abrupt oscillations than MISs 5 and 7″ then sea level excursions might even exceed those quoted above.

    Really folks. One meter? Is that all you got at the possible end-Holocene?

  56. Because the thermosteric component was chief in 20th century the 0.2784meter are only in case of continuing 20th century temperature trend. If not there will be even much less change and if cooling occurs due to solar activity multicycle slump, the sea level could be already lower in 2100 than now.

  57. so sea levels continue to rise….even when temps don’t
    ..and temps affect the weather…even when it’s hiding in the bottom of the ocean

    65% of tide gauges show no sea level rise at all…
    …that makes the rest of them null and void

  58. John says:
    November 22, 2013 at 8:29 am
    _________________
    An “Expert” is a drip under pressure
    &
    If he has a brief case under his arm he is a “consultant”.

    Alternatively ;
    An expert is a man who is more than forty miles from home.
    ie; everybody at home knows he doesn’t have a bloody clue.

    In one of the well known SciFi stories of future times one of the Galaxy’s leading scientists has built his reputation on the reading and analysis of long past science research.
    No on ground science or observations was necessary anymore in that world of the future for science to be practiced
    That “future” science is apparently already here as it appears it wasn’t neccessary for Horton, Rahmsdorf or others to do the basic on ground research for themselves.
    They just read up on what past researchers have published, selected those papers that supported their proposition and Lo!, the case is proven.!

  59. Hey, I have a great idea! We have many scientists, engineers, and other experts posting here. Let’s take a poll of people’s estimates of sea level rise and get it published. It would be at least as valid as Rahmstorf et al’s paper, and most likely, more so.

  60. Interestingly, I note comments about the recent Super Typhoon, warmed seas, higher sea levels etc.

    The reason for the storm surge – funneling perchance!

  61. Why not stay with Chao, Yu & Li (Science April 11th 2008) and forget the rest of the speculation about sea level change? They studied the sea level data of the twentieth century and corrected it for all water held in storage by dams built since the year 1900. When so corrected, global sea level rise became linear for the past 80 years. Something that has been linear that long is not about to change anytime soon. The slope of their 80 year sea level curve was 2.46 millimeters per year.That works out to 24.6 centimeters per century or just a little under ten inches. Certainly nothing like 20 feet as per Al Gore or several meters that these other guys are dreaming up.

  62. So how “ambitiuos” should we be to “prevent” a 50 cm differential (50 cm versus 100cm, stated in the article) in sea level? I’m pretty sure even the peeps that believe this forcast have more pressing issues to deal with in the next eighty years, and better uses for their money than carbon taxes and cost ineffective green technologies.. Brady V Manning is more compelling, and 25 cm is much more likely. Yawn. Broncos 27, Patriots 24 in OT.

  63. Re: Ken Gregory @ 12:09 pm wrote:

    “The global sea level rise according to satellite data as interpreted by the University of Colorado Sea Level Research Group has declined from 3.23 mm/yr during 1993 – Dec 2003, to 2.46 mm/yr during Jan 2004 – Aug 2013, without GIA adjustment, as shown:
    http://www.friendsofscience.org/assets/documents/FOS%20Essay/GlobalSeaLevel.jpg
    ________________
    Yes it did, but at the time, the University of Colorado Sea Level Research Group put up this graphic:

    Which said not 3.23 mm/yr but only 2.8 mm/yr. Over time, the history of satellite sea level data has been rewritten.

    Remove those changes and that 2.46 mm/yr will be further reduced to 2 mm/yr or less.

    Cheers!

  64. 1sky1 says:

    November 22, 2013 at 11:00 am

    “The fact of the matter is that there aren’t 90 persons in the world who are truly expert on the complexities of sea-level variations.”….
    =============
    Wouldn’t one be enough ?

  65. Fault with the premise in the OP: past sea level rise is best indicator of future sea level rise? Too much emphasis on statistics, and no deference to physics.

    What of the increase in sea level in the satellite record (34 years) being about twice as much as the tide gauge record of the last century?

    Personally, I don’t think there is quite enough satellite data to indicate a statistically significant acceleration, although if the current rate continues for another 10 years, then I will say that sea level rise has accelerated. I note the other points made in the article, but it sems this obvious comparison, even at a cursory level, is completely overlooked, and even though both values appear in the article (1.7 mm/dec v 3.2 mm/dec). They just don’t get compared. Because of this obvious omission, the article lacks a balanced viewpoint. It’s one-sided.

  66. It is an enduring but rather quiet thesis of the IPCC that sea level rise is accelerating. I have played with quite a lot of the tide gauge records, and can’t find any evidence, but a man called Church from Australia seems to be both judge and prosecutor. Chap 13 in AR5 (Church as CLA) says bluntly “Based on proxy and instrumental data, it is virtually certain that the rate of global mean sea level rise has accelerated during the last two centuries, marking the transition from relatively low rates of change during the late Holocene (order tenths of mm yr–1) to modern rates (order mm yr–1).”

    Take one nice long tide gauge record like that of New York. I have tried many tricks on the data to try to get it to accelerate, but it seems jammed on about 2.9mm/a. But I haven’t tried Church’s trick of principal component analysis, because after the Hockey Stick and Warmer Antarctic debacles I feel just a little nervous about such techniques. He finds an oceanic hockey stick kicking in around 1920, which is sort of early for AGW to be the cause – if you assume that the principal component analysis is true.

  67. Re:barry @ 9:20 pm

    What of the increase in sea level in the satellite record (34 years) being about twice as much as the tide gauge record of the last century?

    Personally, I don’t think there is quite enough satellite data to indicate a statistically significant acceleration, although if the current rate continues for another 10 years, then I will say that sea level rise has accelerated. I note the other points made in the article, but it sems this obvious comparison, even at a cursory level, is completely overlooked, and even though both values appear in the article (1.7 mm/dec v 3.2 mm/dec). They just don’t get compared. Because of this obvious omission, the article lacks a balanced viewpoint. It’s one-sided.

    mm/dec? Did you mean mm/yr?

    As I’ve pointed out in my other posts on this page, remove the additions, corrections and other manipulations from the satellite record, and sea level these last ten years is probably no more than 1.9 mm/yr. Besides, an honest evaluation of the tide gauge data, not the cherry picked and massaged data in the Church & White papers and thier followers, yields a current value of about 1.6 mm/yr.

  68. I wonder how many of the sea level expert scientists who have produced papers to refute the so called consensus on rising sea levels were included in the survey, or was this just a survey of the true believers without any chance of a dissenting voice. Is it not slightly unusual that in a report of this nature there was no mention of any scientists in the survey who said that there would be minimal or no rising sea levels in the future, particularly in the light of there being no global warming over the last seventeen years? But when you see that this rubbish has followed so much previous rubbish put out by Rahmstorf of the Potsdam Institute of Climate Research, then we read what they say, have a smile and then press the delete button.

  69. ” Keitho says:
    November 22, 2013 at 12:09 pm

    What I fail to understand is what causes the rather large oscillation in the rate of sea level change. I mean it is a huge lump of water ( 1.3 billion cubic kilometers ) but its rate of change changes quite rapidly. Why?”

    The biggest factor for short term variation (up to several years) is ENSO, where there is strong correlation between the la Nina phase and lower sea level. This appears to be mainly the result of shifts in rainfall patterns, with more rainfall over land during la Nina and less during el Nino being the most likely explanation. There appears to also be a ~60 year oscillation in the rate of sea level rise, though this is less clear than the ENSO influence. Some of the rate of rise in the satellite record (especially through ~2005) may be attributable the satellite record corresponding to upward part of ~60 year oscillation. Untangling natural variation in sea level from a longer term secular trend is a challenge.

  70. As Steve Case @ 5:37 and Ken Gregory @ 12:09 pm point out, sea level data sets (like temperature data sets) have been adjusted and molested to the point that they simply can’t be trusted. Decades of time and billions of dollars were spent collecting these data sets, and now climastrologists have rendered them useless.

    Climatology is an honorable profession currently populated by dishonorable people. These people should be jailed for fraud.

  71. john piccirilli says:
    November 23, 2013 at 8:48 am
    “I wonder what these so called experts would have said if they lived in russia under Stalin”

    Stalin loved pseudoscientists. Trofim Lysenko. The ones that got shot were the geneticists.

  72. The way the experts were selected could only lead to an extreme result. The experts selected had published multiple times on sea level, likely having benefited from dire predictions in one study scaring up money for the next study. This new “study” should scare some more money out of the coffers of governments and foundations. Reporting that there is little to worry about might shut off the funding.
    Pardon me for being so cynical, but to this outsider, it looks like the manner of funding scientific study guaranties exaggerated results. If they were paid to be correct, rather than alarmist, would the results be less alarmist? “You get what you pay for” applies.

  73. I have been living in Queensland, Australia, since 1979.Up until recently I lived a couple of blocks from the beach and have never noticed the water any further up the beach in this time.
    Most,if not all of these Doom Sayers have probably never even seen the Beach.As some people often say “A lie can be half way round the world before you have gotten your pants on”
    What they tend to forget, is that after a while people stop taking any notice of what you say.

  74. VIRTUALY CERTAIN:
    Virtual
    1. Existing or resulting in essence or effect though not in actual fact, form, or name: the virtual extinction of the buffalo.
    2. Existing in the mind, especially as a product of the imagination. Used in literary criticism of a text.
    3. Computer Science Created, simulated, or carried on by means of a computer or computer network: virtual conversations in a chatroom

    Yup they are “virtually” certain

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