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
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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]](http://wattsupwiththat.files.wordpress.com/2013/11/holgate-9-station-with-std-dev-digitized1.jpg?quality=83)
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]](http://wattsupwiththat.files.wordpress.com/2013/11/puls_21.jpg?quality=83)
– 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.
Related articles
- IPCC’s New Estimates for Increased Sea-Level Rise (yaleclimatemediaforum.org)
- Scientists Find That Sea Level Rise Is Much Slower Than Expected…No Human Fingerprint (notrickszone.com)
- IPCC sea level exaggeration (wattsupwiththat.com)
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”.
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.
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.
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?
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.
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?
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.
Dr. Bob says” will all regulations be driven by gw”……….they already are. The tyrant in the
White house and most pols are pushing gw agendas.
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.
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.
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.
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!
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.
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.
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.
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?
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”..
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
When someone is wrong repeatedly in an area in which they claim expertise, at what point should they no longer be considered experts?
In 2010 I made a single glance graphic about sea level linearity:
http://s6.postimg.org/cdfc600dt/image.jpg
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.
I used to think Wan King was the capital of China until I read Rahmstorf…..
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.
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/
Hooray for rising sea levels.