Asymptoting Sea Level Rise

http://globalwarmingart.com/images/1/1d/Post-Glacial_Sea_Level.png

Image courtesy of globalwarmingart.com

From World Climate Report: Sea Level History Lesson

We are sure you’ve heard that sea level is rising? We conducted a web search on “Global Warming and Sea Level” and nearly 3.5 million websites are immediately located. And before you conduct the search yourself, you already know what you will find. The earth is getting warmer due to the buildup of greenhouse gases, the warmer sea water expands causing sea level to rise, and most of all, you will read all about the ice melting throughout the world pouring fresh water into ocean basins causing sea level to rise far more. Alarmists insist that the worst is just around the corner, and the sea level rise will accelerate or even quickly jump to a new level given some catastrophic collapse of large sheets of ice near the fringes of the polar areas. Coastlines will be inundated, the human misery will be on a Biblical scale, ecosystems will be destroyed … this goes on for millions of websites!

But things aren’t really so simple.

The United Nations’ IPCC group presents the graph below (Figure 1) regarding eustatic (or global) sea level over the past 125 years, and as noted by the IPCC and by many others, the rate of rise is definitely higher in the most recent 50 years than the first 50 years of the record. So, it becomes quite possible to suggest that sea level rise is accelerating, and may continue to accelerate in the future. Alarmists can certainly find material in the IPCC document to bolster their claim that sea level is not only rising, but the rate of the rise is increasing.

Figure 1. Annual averages of the global mean sea level based on reconstructed sea level fields since 1870 (red), tide gauge measurements since 1950 (blue) and satellite altimetry since 1992 (black). Units are in mm relative to the average for 1961 to 1990. Error bars are 90% confidence intervals. (figure source IPCC)

Back in August of 2008, scientists from all over the world attended a workshop entitled “Empirical Constraints on Future Sea-Level Rise” and they just published a summary of their findings in the Journal of Quaternary Science. Somewhere along the way, they decided to refer to the group as “PALSEA” for PALeo SEA level working group.

The PALSEA group begins their article noting:

The eustatic sea-level (ESL) rise predicted for the 21st century represents one of the greatest potential threats from climate change, yet its magnitude remains a subject of considerable debate, with worst-case scenarios varying between 0.59m and 1.4m. In general, the basis for this debate revolves around the uncertainties in the dynamical behaviour of ice sheets (such as loss of buttressing through ice shelf break-up or enhanced ice flow through water lubrication of the ice sheet base), which may lead to a nonlinear sea-level response to climate change.

Note that the authors are talking about worst-case scenarios leading to “0.59m and 1.4m”; if the trend of the past 50 years continues (from Figure 1), sea level will rise around 0.20 meters (around 8 inches) by 2100. The PALSEA team notes that measuring sea level can be tricky “Because changes in ice mass will also cause changes in regional (due to gravitational and rotational feedbacks) and global (due to volume) sea level, the changes in sea level at a particular coastline record the difference between vertical motions of the land and sea, commonly referred to as relative sea-level (RSL) changes. Such isostatic effects are a function of the distance from the large ice sheets.”

Now for the good stuff! The PALSEA team states that

Given a broad range of emission scenarios the IPCC AR4 predicted global warming of between 1.18C and 6.48C during the 21st century. The last time that a global warming of comparable magnitude occurred was during the termination of the last glacial period (TI).

Furthermore, they write

Given this evidence for periods of rapid warming during TI, at least some of this warming occurred on decadal to centennial timescales. Because of the general similarity between the magnitude and rate of warming predicted for the 21st century and the warming that occurred during certain periods of TI, it is interesting to consider rates of sea-level rise during TI as a case study of the response of sea level to climate change.

The PALSEA group presents the graphic below (Figure 2) showing three different rates of sea level rise following an increase in temperature. As seen there, sea level could rise exponentially (as suggested by many climate change alarmists), it could rise linearly, or it could rise and then level off (the “asymptoting” curve).

Figure 2. An illustrative sketch of three models (black) for the time-dependent response of sea level to a perturbation in temperature (red) (from PALSEA, 2010).

Here’s what they conclude:

Therefore, we suggest that option 1 (exponential sea-level rise) is extremely unlikely. …An exponential increase in rates of sea-level rise with respect to temperature would result in 21st-century sea-level rise an order of magnitude larger than estimates using alternative patterns of response – it is an important result that the palaeo-sea-level data rule out such a response.

Finally, they write “the palaeo sea-level data suggests that sea-level rise related to current warming may be rapid at first and slow over time.”

Basically, their analysis of what happened in the past favors the “asymptoting” curve that is quite different from the exponential curve favored by those proclaiming the worst is yet to come! Mother Nature showed us in the past how sea level responds to warming – we at World Climate Report are listening!

Reference:

PALSEA (the PALeo SEA level working group: Abe-Ouchi, A., Andersen, M., Antonioli, F., Bamber, J., Bard, E., Clark, J., Clark, P., Deschamps, P., Dutton, A., Elliot, M., Gallup, C., Gomez, N., Gregory, J., Huybers, P., Kawamura, K., Kelly, M., Lambeck, K., Lowell, T., Mitrovica, J., Otto-Bleisner, B., Richards, D., Siddall, M., Stanford, J., Stirling, C., Stocker, T., Thomas, A., Thompson, W., Torbjorn, T., Vazquez Riveiros, N., Waelbroeck, C., Yokoyama, Y. and Yu, S.) 2009. The sea-level conundrum: case studies from palaeo-archives. Journal of Quaternary Science, 25, 19-25.

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88 thoughts on “Asymptoting Sea Level Rise

  1. All these predictions are based on interpolation beyond the last known data point. Mathematically this is not the correct methodology because all climate/ice cover/sea level graphs are representations of a chaotic system with many variable inputs, any interpolation like this will produce the wrong answer! We only know what the sea level is today but not tomorrow.

  2. This is kinda where I am. Even if “average global temps” are meaningful — which I’m not sure about — and eve if they’re rising — which I’m not sure about — I’m not in any way convinced the sea levels are prone to catastrophic rise. Antarctic ice 2 miles thick and at temperatures of 40 below isn’t going to melt at 30 below. Glaciers melting over the next three centuries aren’t the same as 40 days and 40 nights of world wide rain.
    And in the absence of oceans overwhelming the current coast line — exactly what is bad about warming?

  3. Jerejeva et al., 2008 includes an excellent ESL reconstruction back to 1700 AD.
    Modern ESL rise is not anomalous, just like the late 20th century warming was not anomalous.

  4. If sea level rose to dangerous levels the simply low cost solution would be to channel it inland to deserts or other places where water is desperately needed. Problem solved, jobs created, lifestyle quality raised, poverty alleviated.

  5. When I tell people that 18000 years ago the sea was 120 meters below the actual level, people just smile. I believe 95% of people that defend AGW, have never looked at, or have been told, about the first image in this post…
    Ecotretas

  6. Asymptoting SLR better hurry up then. At my place on the east coast of Aust SLs are 16 inches [40 cms] lower than they were 47 years ago and falling.

  7. As a Louisiana boy I worry about sea level rise. Chalmette Battlefield, a low lying land area where the battle of New Orleans was fought in 1815, is still dry ground.
    The French Quarter, site of the founding of New Orleans in 1718, was built on a bit of dry ground beside the Mississippi River, and only a couple of feet above sea level, can be seen as dry ground in satellite photos of the city the day after Katrina.
    No sea level rise from the land of the DIX (ten dollar french note originating in New Orleans, and source of “Dixie”)

  8. What’s the difference in Volume of 1 Litre of Water at 5 degrees celsius and 1 litre of water at 15 degrees celsius?

  9. Gee! Look at how warming oceans rose in the past. What a novel idea… for climate researchers.
    Good for them and interesting results.

  10. When the elites of the Alarmist movement stop buying expensive sea-front properties, then I shall take notice of the risks and hazards of sea-level rise.
    When they stop flying to conferences, I shall take note of the danger of CO2.
    When they stop lecturing and start doing, then I will listen, until then their own actions betray their real thoughts. They do not believe in CAGW either!

  11. Since there isn’t much sea level rise, what does that indicate about ocean heat storage (heat in the “pipeline”)? The more “Greenland melts” and raises sea levels, the less that rise can come from ocean heat storage, they are mutually exclusive.

  12. Anthony, please put a warning at the top that this article contains graphic glacial violence that might be not be suitable for younger ice huggers.

  13. ‘Rapid at first’ doesn’t sound very reassuring to me. The article says that the evidence from two independent studies:

    “…seems to indicate that the rapid demise of ice sheets in a climate similar to today is certainly a possibility.”

    It also says:

    The RSL and modelling results discussed in the paragraph above tentatively suggest that for the conditions warmer than pre-industrial levels the Greenland and West Antarctic ice sheets may be vulnerable to reductions in volume. Modern observations of the Greenland and West Antarctic ice sheets consistently show evidence of rapid responses to a warming climate, including the collapse of the Larsen B ice shelf, the acceleration of ice streams and increasingly negative ice mass balance (e.g. Velicogna and Wahr, 2006; Bamber et al., 2007; Rignot et al., 2008; and see summary by Alley et al., 2005). However, it is not clear today whether these rapid processes might have a larger-scale impact on the ice sheets with upstream repercussions, or whether they are limited to the fringes and a new stable equilibrium is achieved. Such direct observations of the modern acceleration in ice sheet dynamics constitute the foundation of a deeper understanding of the response of ice sheets to climate change but they still are of relatively short duration (typically several decades). However, because the rapid changes observed in modern ice sheets are in general agreement with palaeo-observations of the response of ESL to rising temperatures, the rapid response of ice sheets to climate change is a serious possibility.

    And also:

    RSL and modelling reconstructions of the LIG suggest that we are moving into a climate regime when the Greenland and West Antarctic ice sheets will become increasingly unstable (with the caveat on the need to better understand isostatic effects for the LIG). Direct observational evidence confirms this assertion. Furthermore, the response model revealed by the palaeo sea-level data suggests that sea level rise related to current warming may be rapid at first and slow over time.

    I don’t think any of this is cause for complacency, especially as the article says:

    Note that if the climate forcing increased exponentially over time then the sea-level rise might follow this trend…

  14. Geez, I think I must’ve gotten up on the wrong side of the bed.
    We are sure you’ve heard that sea level is rising? We conducted a web search on “Global Warming and Sea Level” and nearly 3.5 million websites are immediately located.
    Well, without doing the search myself, it was 1) almost certainly web pages, not web sites. And 2) the 3.5 million is almost certainly a grossly inflated count. I can’t imagine why search engine estimates are so grossly inflated. They’re so bad I never use them to compare the database size of different search engines.
    with worst-case scenarios varying between 0.59m and 1.4m.
    Doesn’t good science look at all possibilities? Why are these cretins JQS scientists only looking at the best and worst case of the worst case? Can’t they bring themselves to consider that maybe, just maybe there are best and worst cases of the best case to consider. (If I were a reviewer or editor, what would be the response if I asked if the best case of the worst case made any sense? Actually, I’d probably ask if the worst case of the best case was worse than the best case of the worst case. I’d have to do it over the phone – no, on YouTube – with cigar and a Groucho Marx impersonation.)
    As seen there, sea level could rise exponentially (as suggested by many climate change alarmists), it could rise linearly, or it could rise and then level off (the “asymptoting” curve).
    Ever after learning a little bit about Esperanto, I’ve become a lot more tolerant with people who verbize nouns. However, they seem to have crossed my vertical asymptote. Why are these idiots WC reporters using aysmptoting but not exponentiating? Besides, if you look backward in time, that exponential has an asymptote itself. Grr.
    If we assume we’re only looking forward, they could say exponentially, linearly, or asymptotically. Or refer to an exponential, linear, or asymptotic rise.
    Whew. I think I feel better. Here’s to hoping that the comments below are useful.

  15. John Marshall says:
    August 10, 2010 at 3:19 am
    All these predictions are based on interpolation beyond the last known data point. Mathematically this is not the correct methodology because all climate/ice cover/sea level graphs are representations of a chaotic system with many variable inputs, any interpolation like this will produce the wrong answer! We only know what the sea level is today but not tomorrow.

    Read the article cited in this post – it’s not about ‘interpolation’ at all, but about the study of palaeoclimate data in an effort to draw analogies with current climatic conditions and come to some conclusions about possible and likely sea level rise.

  16. I’ve been posting for years that sea level is currently rising at about 1/2 the average for the last 22,000 years. If you look at the first chart you will see that about 22,000 years ago sea level was about 130 meters below the current level. 130/22,000 equals 0.0059 meters per year (0.59 meters per century). The current rate of sea level rise is 3.2 +/- 0.4 mm/yr. That works out to 0.32 meters per century or 54% of the 22,000 year average.
    In response, I’ve been told that looking at a 22,000 average is “deceiving”! Huh? Looking at 22,000 years is deceptive compared to a prediction?
    I’ve also been told that 22,000 years ago we didn’t have cities on the coast so the comparrison doesn’t matter. Huh? Suddenly because we build cities sea level isn’t supposed to change?

  17. Darren Parker says:
    August 10, 2010 at 4:40 am
    What’s the difference in Volume of 1 Litre of Water at 5 degrees celsius and 1 litre of water at 15 degrees celsius?

    Since a liter is a fixed volume (1 liter), the question is meaningless. The answer is, of course, 1 liter.
    I think what you meant is:
    If you take one liter of water at 5C and warm it to 15C what is its volume?
    The expansion coefficient of water is 2.1, so 1 liter of water warmed by 10 degrees C becomes 1.0021 liters.

  18. If you want to see the historic change in sea level look to Florida near Miami. Off shore about 2 miles and 120 feet down is an old coral reef. Now go inland about 3 miles and you find an old quarry used to build walls and building in the early years of settlements. That is made of old coral reef. So we have known boundries available to us for what can be not what will be.
    Or the old fort at Saint Augustine. Made of coral quarried from inland above ground.

  19. Darren Parker: August 10, 2010 at 4:40 am
    What’s the difference in Volume of 1 Litre of Water at 5 degrees celsius and 1 litre of water at 15 degrees celsius?
    Nothing, of course.

  20. A 9,000 year old city is 36 metres underwater. They were warned to stop driving their Humvees, but failed to listen.
    http://news.bbc.co.uk/2/hi/south_asia/1768109.stm

    Saturday, 19 January, 2002
    Lost city ‘could rewrite history’
    By BBC News Online’s Tom Housden
    The remains of what has been described as a huge lost city may force historians and archaeologists to radically reconsider their view of ancient human history.
    Marine scientists say archaeological remains discovered 36 metres (120 feet) underwater in the Gulf of Cambay off the western coast of India could be over 9,000 years old

  21. Step number one is create fear. Use pictures and graphs. Then find a cause and blame the culprit. Next step is promise a solution and force people to put money on the problem.
    We have many people to put on this because we saved 500 million people recently from swine flu.

  22. The first graph sure puts things into perspective. No wonder many geologists are so sceptical of CAGW.
    —–
    “No significant acceleration in the rate of sea level rise during the 20th century has been detected”
    IPCC Working Group I – Executive summary

    Here is a little something for warmists worried about coral atolls sinking.
    “Atolls are created by sea level rise, not destroyed by sea level rise.”
    Willis Eschenbach
    “The atoll falls along with the sea level. When the sea level rises, wind erosion decreases. The coral grows up along with the sea level rise. ”
    Solomon Star

  23. So what they are saying is that if you tied someone to the beach, in hopes of drowning them, they would die of old age before they ever got wet.
    Do people realize that even their worst case is so slow and so little, that people won’t even notice? 8 inches is one cement block. Better get started, we’ve got 100 years to build that wall, and so far no one has noticed any sea level rise at all.

  24. Would I be right in thinking that any of the water in the oceans below about 3 degC would shrink in volume as it warms rather than swell?
    [Reply:] Yes, until it got above about 4 degC. RT-mod

  25. Icarus says:
    August 10, 2010 at 5:39 am
    “”John Marshall says:
    August 10, 2010 at 3:19 am
    All these predictions are based on interpolation beyond the last known data point. Mathematically this is not the correct methodology because all climate/ice cover/sea level graphs are representations of a chaotic system with many variable inputs, any interpolation like this will produce the wrong answer! We only know what the sea level is today but not tomorrow.”
    [Icarus’ response] Read the article cited in this post – it’s not about ‘interpolation’ at all, but about the study of palaeoclimate data in an effort to draw analogies with current climatic conditions and come to some conclusions about possible and likely sea level rise.””

    That’s what I was seeing in the article. And based on data over the past several hundred years (I’ll take it as “good enough” actual sea level data) and the fact we know we’re currently observing the sea levels coming out of a glaciation, and given the steady small rise in sea levels (not acceleration) data gatherers are reporting now; it looks to me like we’re currently riding along the top level of the asymptote. It looks like they’ve laid out a decent case of how sea levels have behaved coming out of a glaciation.
    My only quibble is any speculation that temperatures are going increase dramatically, which is a whole ‘nother topic. If temperatures rise 5-6C over some reasonably short period (if my granny had wheels, she’d be a wagon – h/t to ? in a recent post), I’m with them – the sea levels will probably rise rapidly and then begin to level off as shown in the first figure.
    But right now, my granny doesn’t have wheels.

  26. What they actually say in their conclusion is that sea level rise is likely to be constrained to a of up to1 m. They are no more assertive than ‘loose limits’ which places their constraints in the same range as current estimates e.g. Rahmstorf (2007a) 0.5–1.4m.
    “Using palaeo-data and direct observations, it is possible to put loose limits on just how rapidly we might expect sea-level rise to occur over the next century. For example, one may expect sea-level rise over the next century to fall between the lower limit of 20th-century sea-level rise (0.12m per century; Meehl et al., 2007) and the sea-level rise at the conclusion of TI (1m per century; Carlson et al., 2008).”
    It is also clear that if their upper loose estimate of 1 m/century is to be realized then rates of rise must accelerate above today’s rate. In other words we cannot have yet reached the the rate they consider to be “rapid at first”.
    It is also clear that historically an initial rise at a high rate of 1m/century is sustained for centuries before reducing asymptotically.
    In short they are

  27. Just because an area that clearly used to be above water is now submerged doesn’t automatically imply that the sea level rose. It also could be the case that the land fell. For example, Alexandria, Egypt sunk into the sea around the 4th century BC and now lies under about 8 meters of water.

  28. Darren Parker says
    What’s the difference in Volume of 1 Litre of Water at 5 degrees celsius and 1 litre of water at 15 degrees celsius?
    I am not sure if you meant this as a joke or a mistakenly framed real question.
    Of course 1 litre is 1 litre at any temperature.
    If you are asking how much a litre of water would expand if raised from 5C to 15C I think the answer is 2ml. The coefficient of volume expansion is 207 x 10 power-6.
    For 1000 ml and a 10C rise this is 1000 x207 x10 divided by 1000000 which is 2.

  29. This is a great graph. If only people would use a little more critical thought, they might realise that sealevel measurements are nontrivial; just like air sampling from ice cores and global temperature measurements. Australias baseline sea level measurement project has always seemed to me to be a sensible way to assess the risk of rising sealevels. If cagw were real, that project would give a great early warning of the first signs of an increased rate. No sign yet.

  30. As changes in sea levels are dictated by processes driven by deterministic chaos, it is impossible to make accurate predictions of future behaviour based on historic events. In addition, because of the inherent non-linearity, historic trends have no meaning.
    Sea levels will continue to oscillate up and down, and as ever, life will have to adapt to the changes. It’s a pity the authors of this paper did not take account of this when producing their paper, perhaps they will realise this in the future and withdraw it.
    This has happened before:-
    Climate scientists withdraw journal claims of rising sea levels.” – Guardian, Feb 2010.
    http://www.guardian.co.uk/environment/2010/feb/21/sea-level-geoscience-retract-siddall

  31. [Reply:] Yes, until it got above about 4 degC. RT-mod
    This is true for fresh water, but not for the ocean. Salt ocean water has a freezing point below zero and gets denser close to the freezing point.

  32. pouncer asked on August 10, 2010 at 3:30 am:
    “I’m not in any way convinced the sea levels are prone to catastrophic rise… And in the absence of oceans overwhelming the current coast line — exactly what is bad about warming?”
    In the hysterical science of solipsism known as catastrophic AGW, any possible aggregate rise in temperatures or sea levels – or really, any change in anything at all – conjures the frightening images of a Roland Emmerich film (The Day After Tomorrow, 2012) happening in the believer’s kitchen, back yard, or college campus.
    Honestly I think the hysterical CAGW solipsist is mentally very much like the sun worshipping Mayan savage of Mel Gibson’s Apocalypto.

  33. DaveF says:
    August 10, 2010 at 6:33 am
    Would I be right in thinking that any of the water in the oceans below about 3 degC would shrink in volume as it warms rather than swell?
    [Reply:] Yes, until it got above about 4 degC. RT-mod
    ——————————–
    Only if it’s freshwater!
    [Reply] Oops, correct. Sea water densest at around 0 degC. Mea Culpa. RT-mod

  34. There is proof all around us that we can and HAVE survived far worse global warming and coastal flooding. The result is the world we live in today. I’m also not aware of any reason why sea levels won’t continue to rise if that is the direction natural processes take us. Surely everyone is aware it has happened before, and if not then the following example should provide clarity.
    http://www.culture.gouv.fr/culture/archeosm/en/fr-cosqu1.htm

  35. The Proceedings of the National Academy of Sciences (PNAS) published a paper by Vermeer and Rahmstorf (2009), “Global Sea-level Linked to Global Temperature.” In this paper they devised a preposterous model for sea level rise that fits all the needs of a dedicated alarmist.
    It stunned me to see this nonsense published by the NAS. The consequences of their model are simply bizarre. You can see links to the logical consequences of their model here. There is some math, but you can get the gist of it by skipping the math and reading the text and observing the plots.
    ClimateSanity

  36. latitude says:
    August 10, 2010 at 6:28 am
    > So what they are saying is that if you tied someone to the beach, in hopes of drowning them, they would die of old age before they ever got wet.
    Only if he’s (they’re?) really old. I’d expect dehydration or hypothermia would happen first.

  37. 1) What is the volume of current ice?
    2) Can all that ice melt?
    3) How much ice will end up in the atmosphere?
    4) What is the average slope of all shore lines?
    5) Will the increase in ocean expansion rise linearly with the ia linear increase in melting ice?
    6) Does increase in global temperature increase snow fall in areas of current glaciers/ice packs?

  38. Makes some sense, a good amount of sense> Any geologist can tell you that “the present is the key to understanding the past” and any historian will tell you failure to understand the past will impede your understand of the present. Makes sense to me.

  39. Steve Goddard “The consensus among geologists is that climate scientists have no historical perspective, and idea what they are talking about.”
    Really?
    The European Federation of Geologists:
    “The EFG recognizes the work of the IPCC and other organizations, and subscribes to the major findings that climate change is happening, is predominantly caused by anthropogenic emissions of CO2, and poses a significant threat to human civilization.
    It is clear that major efforts are necessary to quickly and strongly reduce CO2 emissions. The EFG strongly advocates renewable and sustainable energy production, including geothermal energy, as well as the need for increasing energy efficiency.”
    http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change
    “The Geological Society of America (GSA) supports the scientific conclusions that Earth’s climate is changing; the climate changes are due in part to human activities; and the probable consequences of the climate changes will be significant and blind to geopolitical boundaries. Furthermore, the potential implications of global climate change and the time scale over which such changes will likely occur require active, effective, long-term planning.”
    I guess they must have come to those conclusions without the help of climate scientists then?

  40. Ecotretas says: August 10, 2010 at 4:13 am
    “When I tell people that 18000 years ago the sea was 120 meters below the actual level, people just smile. I believe 95% of people that defend AGW, have never looked at, or have been told, about the first image in this post…”
    Especially as this can be put into a human history context. 10,000 years ago, with sea level over 50 metres lower we start to see evidence of agriculture and civilisation and facts like the UK and France were connected by land. Even things like the Pyramids were built not long after a significant recent rise in sea level.

  41. Steve,
    Finding an ancient city under the water may not have anything to do with the average change in the sea level, of course.
    Everyone who visited the ancient Troy ruins could see that Trojans’ landing stage ramp for hauling cargo from ships to town is about a mile from the shore now.
    It doesn’t mean that the sea level at Troy somehow got so much lower in 3000 years, of course. But it means that some geological processes, such as river drift accumulation or seismic collapses (remember Lisbon disaster?), can dramatically change any shoreline in relatively short time, possible changes in sea level being far less important.

  42. http://en.wikipedia.org/wiki/Asymptote
    In analytic geometry, an asymptote of a curve is a line such that the distance between the curve and the line approaches zero as they tend to infinity.
    So what is infinity in regards to sea level? Infinite height? Impossible. Infinite time? The Solar System won’t last that long.
    So what do they mean by asymptote?

  43. The best work on Holocene sea levels was done by Rhodes Fairbridge 40 years ago. I’ve’ seen nothing better since. Based on that work, the worst cast scenario postulated by the IPCC would put the ESL in 100 years at the average level for the entire Late Holocene (+1.25m).
    Further, I read no mention of the Laurentide. A couple of the largest pulses in Early Holocene sea level rise occurred when the bounding moraine of the Laurentide Glacier gave way and caused most of the water volume of Lake Laurentide to dump into the ocean. It was not a rapid sea level rise due to a rapid warming event, but rather an event caused by the build up of melt water behind a dam that gave way.
    Notice also the way the presenters of the data choose the measuring stick. A 150 unit rise in 100 years seems really big until one realizes how much a millimeter is. That’s less than six inches. The ignorant dolts that buy into these arguments are impressed by big numbers with no sense of what they really mean. The IPCC realized this when they converted the projections in the first report from meters to centimeters. A prediction of 0.64m sea level rise in 100 years became 64cm because Americans knew 64 was a bigger number than 0.64. It is interesting to note also that in the public presentation of the graph, the x-axis was narrowed considerably and the y-axis raised so the apparent slope of the curve steepened. It’s propaganda behind a political ideology, that’s all.

  44. Good article. Gradual sea level rise will be a problem, but not an insurmountable one.
    The predictions seem roughly around the IPCC ones.
    The longer term graph of sea levels shows just how stable sea levels have been over most of human civilisation. Kind of lucky, as it meant you didn’t have to keep moving your port cities all the time.
    The idea that climate scientists don’t know about events on geological time scales is a bit silly.

  45. stevengoddard says:
    August 10, 2010 at 6:22 am
    [b]A 9,000 year old city is 36 metres underwater. They were warned to stop driving their Humvees, but failed to listen.[/b]
    Well, at least we now know what happened to Atlantis, and where to look for it.

  46. Well the sea level in North Wales has not risen back to levels which it was at over 700 years ago. See below.
    “The castle’s other remarkable feature is the defended “Way from the sea,” a gated and fortified stairway plunging almost 200 ft down to the foot of the castle rock. Once, this gave access to supplies from the sea, but the tide level has since receded, leaving Harlech somewhat isolated upon its rock. During Madog ap Llywelyn’s uprising of 1294-95, this maritime lifeline proved the savior of the garrison, which was supplied and victualled by ships from Ireland.”
    http://www.castlewales.com/harlech.html

  47. blockquote>World Climate Report might be listening but will the warmists?
    I don’t know what ‘warmists’ will do, but being a good skeptic, I decided to read the paper myself instead.
    As a result, I discovered that the paper discusses various comparative periods of warming, and not just the TI period. Unfortunately, these appear to have escaped the attention of the author at World Climate Report. The author writes, “here’s what they conclude”, and, “finally” – about text in the middle of the article.
    Here is the actual conclusion of the paper.

    “Although none of the periods we have considered in detail here (i.e. T1, Holocene, LIG) present exact analogues for future change, each is a useful case study to understand the evolution of sea level in warmer climates (LIG), transitional climates (T1) or broadly similar climates (Holocene). Each case study has its limitations and strengths. For example, T1 represents a cooler climate with greater ice volume than at present but the magnitude and rate of warming during certain periods in the transition may be compared to changes imposed by anthropogenic
    greenhouse emissions. Although the magnitude of the sea-level response to a temperature perturbation must be a function of the remaining ice volume (and therefore will be reduced in the future compared to T1) there is a lot to learn from T1. The LIG had different orbital and GHG forcing to future projections but nevertheless represents an example of a warmer climate state with reduced ice volume. Finally, the Holocene climate had many similarities to today but for much of the late Holocene the climate was relatively stable and so the late Holocene has little to teach us about the response of sea level to large changes in global climate. However, the late Holocene
    provides a key baseline against which to understand future change. Furthermore, changes in RSL and ESL in the early to mid Holocene may be key to understanding future sea-level change. Here we have attempted to consider a few of the many lessons to be learnt from palaeo-data in understanding future change.
    To summarise, RSL and modelling reconstructions of the LIG suggest that we are moving into a climate regime when the Greenland and West Antarctic ice sheets will become increasingly unstable (with the caveat on the need to better understand isostatic effects for the LIG). Direct observational evidence confirms this assertion. Furthermore, the response model revealed by the palaeo sea-level data suggests that sea level rise related to current warming may be rapid at first and slow over time. Using palaeo-data and direct observations, it is possible to put loose limits on just how rapidly we might expect sea-level rise to occur over the next century. For example, one may expect sea-level rise over the next century to fall between the lower limit of 20th-century sea-level rise (0.12m per century; Meehl et al., 2007) and the sea-level rise at the conclusion of TI (1m per century; Carlson et al., 2008). Extreme lower bounds (i.e. outside the range of possibility) can be derived by pre-industrial sea-level rise during the Holocene (0.04–0.07m per century; Fleming et al., 1998), while extreme upper bounds of 2m per century have been estimated by extrapolating the fastest observed ice stream responses to all of the ice streams of Greenland and West Antarctica (Pfeffer et al., 2008) (Table 1).
    We conclude by asserting that palaeo-sea-level and ice sheet reconstructions provide important constraints on future sea level rise. RSL estimates based on palaeo-data are a necessary component to the solid Earth models of GIA used to calculate ESL rise from tide gauge data and ice sheet mass loss from satellite data. Ice sheet models must be able to capture the full range of the dynamics revealed by the palaeo-sea-level record if we are to have confidence in projections of future sea-level rise derived from them.”

    And here is a link for anyone else to read up.
    ftp://ftp.wiley.co.uk/bksadmin/supplier44/JQS_Information/JQS%20Issues/2010/JQS%2025_1%20IPCC%20Review%20Special%20Issue/JQS%2025-1/jqs_v25_i1_Rev.pdf
    (Article begins page 62)
    The WRC author accurately quotes a section from the paper that posits an exponential increase in sea level rise is ruled out. Elsewhere in the paper, it is not ruled out. Interested readers may check out the paper in full to understand the discussion therein.

  48. Since Greenland and Antarctic ice core temperature reconstructions clearly demonstrate Holocene cooling over the last ten thousand years then the sea level rise must be primarily due to mass contribution from glaciers minus isostatic rebound rather than thermal expansion. This mass contribution appears to respond asymptotically from the TI warming event at the end of the last ice age. In other words current sea level rise is related to a warming event 10,000 years ago.

  49. Here’s an expert’s take on sea level ‘rise’
    Professor Nils-Axel Mörner (Former IPCC expert reviewer)
    “So, we have this 1 mm per year up to 1930, by observation, and we have it by rotation recording. So we go with those two. They go up and down, but there’s no trend in it; it was up until 1930, and then down again. There’s no trend, absolutely no trend.”
    Executive Intelligence Review, June 22, 2007 or pdf
    ———
    “It is true that sea level rose in the order of 10-11 cm from 1850 to 1940 as a function of Solar variability and related changes in global temperature and glacial volume. From 1940 to 1970, it stopped rising, maybe even fell a little. In the last 10-15 years, we see no true signs of any rise or, especially, accelerating rise (as claimed by IPCC), only a variability around zero.”
    Select Committee on Economic Affairs Written Evidence [2005]
    I am left with the impression that seal levels have stopped their rise since the end of the last ice age. I’m confused! :o(

  50. Whats the worry? By the time the next ice age is going strong the sea levels will be back down the 150 meters they are up now, and Florida will have four or five times more surface area, and nicer weather. No more hurricanes!
    I would worry more about the manatees dying in the cold near future and going extinct. Has anyone put any effort to develop some sort of shelter for them the next couple of winters?
    Why are the environmentalists not building shelters for them to escape extinction?

  51. Here is the article. You do not seem to need a subscription.
    http://onlinelibrary.wiley.com/doi/10.1002/jqs.1270/pdf
    “Therefore, we suggest that option 1 (exponential sealevel
    rise) is extremely unlikely. Note that if the climate forcing
    increased exponentially over time then the sea-level rise might
    follow this trend, but the exponential response cannot be
    considered a direct function of ice sheet mechanics.”

  52. Thanks, Espen and RT-mod for taking the trouble to reply. Now I take it that the thermal expansion of the sea depends on its average temperature, but a lot of the water seems to be pretty cold, so would it really expand that much? Best wishes, Dave.

  53. theBuckWheat says:
    August 10, 2010 at 6:45 am
    Just because an area that clearly used to be above water is now submerged doesn’t automatically imply that the sea level rose. It also could be the case that the land fell. For example, Alexandria, Egypt sunk into the sea around the 4th century BC and now lies under about 8 meters of water.
    ————————————————————————————————
    Likewise there is a painting in an upstairs room of Harlech Castle at the top end of Cardigan Bay in Wales which shows the waves crashing at the base of the castle walls.
    The painting was done in the 17th Century apparently.
    Today the base of the castle wall is about 1km from the beach. A road, railway line and housing occupy the land between the castle and the sea. It’s possible the land has risen in that time, but it doesn’t look like the sea level has.

  54. Packbear: The UK and France may not have had the sea between them but I suspect there was a really big river to cross. The Rhine, aided and abetted by the Seine and the Thames, in summer, would have had to go somewhere.

  55. Here’s a recipe for making new land (for Polar bears).
    Take one steep long sloping piece of ground; preferrably in some super cold place; but nice and long and high at the top. Choose only pieces of of land that end at a nice big long Fjord; preferrably straight and with water in it connecting to the oceans, so it can enjoy the benefits of sea level rise.
    Deposit a large quantity of ice made from compressed snow; and preferrably a few thousand feet thick; or whatever you feel like; and place it on this sloping ground; so It can slide like an ice skater down into the Fjord, and block most of it, so that not too much sea water can get into the Fjord.
    Notice that since the ice slab slopes downwards at the same angle of the piece of ground leading to the Fjord, that once it gets to the edge of the land where it meets the water, the ice starts to partially submerge; displacing a lot of the sea water, which now starts to partially support the weight of the ice slab as it moves farther out into the Fjord, continuously going deeper into the water.
    You might try as an experiment installing a theodolite on top of the ice, so you can measure the slope angle as the ice advances out over the water, and experiences a continuously increasing upward thrust from the sea water, which of course is denser than the ice resting on it..
    From the change in slope, and the thickness of the ice, you can calculate the average radius of curvature of the bottom of the ice as it gets increasingly bent upwards by the thrust of the sea water. Se level rise should aid in reducing the radius of the bend.
    From the Handbook of Chemistry and Physics, look up the maximum tensile strain limit for ice made out of compressed snow.
    As the ice slab advances, you can recheck your calculations; and at some point you can start collecting bets on when the sinking ice will reach the failure strain limit, and break off a nice big long piece of Polar bear land for the cute creatures to hunt seals on.
    With the oceanic tides sloshing back and forth twice a day; you will likely get a tidal bore rushing up the Fjord under the ice, which will increase the curvature of the bottom of the slab; and make it hard for any7 bettor to remeber whent he last Bear land broke off.
    Right up your results in SCIENCE of maybe Wikipedia, and get eady to be cited by all the new Climate Science students who are in school trying to learn why ice keeps falling off slabs of ice that are sliding down Fjords.

  56. The concept is similar to “low hanging fruit” being the easiest and first picked. Glacial ice in low elevations and low latitudes will be most susceptible to warming induced melting. Thus, once the easy-ice has melted the process ought to slow. That’s not hard to figure out.
    —————————————————
    last termination (TI)
    penultimate glacial termination (TII)
    3rd last termination (TIII)
    and so on

  57. The problem with the word “asymptote” is that it seems so final. That’s because it is introduced (usually) as a curve that approaches a given curve (or line) arbitrarily closely. The idea of a limit as x goes to infinity comes to mind.
    However, with regard to sea level, the idea ought not to suggest finality. Rather, sea level may creep upward until it has an inflection point and begins to fall. World ice mass will begin to grow, sea level will decline, the curve will continue until it approaches another limit (or not).
    How low can it go?

  58. Jimbo says:
    August 10, 2010 at 9:52 am
    IPCC don’t like Mørner, because he looks at the real world.
    IPCC likes model simulations with buildt in CO2 effects, not real world data.
    Remember they have a confirmation bias buildt into their objective paragraph.
    How can such an organisation work for science?
    The answer is; They can not.

  59. stevengoddard says:
    August 10, 2010 at 6:22 am
    i love that line about humvees.
    it is now generally accepted the sea levels have gone up by some 160 meters in the last 20K years.
    however, this indian “Ancient City” is not confirmed YET. NIOT has been unable to provide any new soundings data to prove something resembling a city yet. but, if there was a city, it would be atleast 9000 years old.
    http://www.indianwatchdogs.com/forums/showthread.php?t=22518&p=318768

  60. Keith Battye says:
    August 10, 2010 at 10:48 am
    Likewise there is a painting in an upstairs room of Harlech Castle at the top end of Cardigan Bay in Wales which shows the waves crashing at the base of the castle walls.
    The painting was done in the 17th Century apparently.
    Today the base of the castle wall is about 1km from the beach. A road, railway line and housing occupy the land between the castle and the sea. It’s possible the land has risen in that time, but it doesn’t look like the sea level has.

    The land has fallen in that time. It is far enough south that the isostatic rebound from the last glaciation is making it drop. Someone here did post a little map showing contours of land fall/rise in the British Isles one time – perhaps they could post it again?

  61. The comment about Harlech castle being on the coast in the 17th century made me think. Montreuil sur Mer in France is now many kilometres inland and so is Bruges in Belgium. All of these were established before the 17th century. I also remember seeing in an exhibition in Sydney that the sea was 4 metres higher around Australia at one time (but I cannot remember the date). Is there a consensus about what sea level has been over the last 1000 years? Presumably sea levels rose during the mediaeval warm period and then began to fall again as Greenland became uninhibitable. Sorry I forgot there wasn’t a MWP!
    Then I remembered a very good documentary in the UK called the Incredible Human Journey which traced the history of the human race outside of Africa. Genetic markers and the dating of artifacts have established that the second of two groups (the first one appears to have died out) left Africa about 60000 years ago and crossed the dead sea when the sea level was very low. This group moved and expanded and split into factions that populated all the known world. One of these factions apparently crossed from Russia to Alaska along a coastal route which only exists when the sea level is again tens of metres below its current level. They settled North American and then South America.
    I find all this interesting since I suspect that these dramatic treks across thousands of miles were not driven by idle curiosity. I suspect that climate change was constantly happening and creating famines in one place or another and forcing these nomadic groups to move on.
    So we have strong evidence that the sea level was much lower than it is now and some evidence that it was also quite a bit higher. All these have happened during the short history of modern man and all have been entirely natural. The increase in sea level for the last century seems tiny in comparison.

  62. Darren Parker says:
    August 10, 2010 at 4:40 am

    What’s the difference in Volume of 1 Litre of Water at 5 degrees celsius and 1 litre of water at 15 degrees celsius?

    Or, to put it another way, what is the difference in weight of 1kg of water at 5C and 1kg of water at 15C?
    No, wait…..

  63. @Icarus says:
    August 10, 2010 at 5:23 am
    “…I don’t think any of this is cause for complacency, especially as the article says:
    Note that if the climate forcing increased exponentially over time then the sea-level rise might follow this trend……”
    Well, in that case, we appoint you to worry about it.

  64. Won’t the melting fresh water sources entering the oceans reduce the carbonic acid percentage? Therefore there’s nothing to see in acidic oceans then.

  65. I understand that Dr. Stefan Rahmstorf, of the Potsdam Institute for Climate Impact Research in Germany, is on the record for warning the world at the end of September 2009 of an “unstoppable” two meter sea-level increase. This announcement may have been the inspiration for one or more recent works of dramatic fiction.
    http://www.reuters.com/article/idUSTRE58S4L420090930

  66. theBuckWheat says:
    August 10, 2010 at 6:45 am
    Just because an area that clearly used to be above water is now submerged doesn’t automatically imply that the sea level rose. It also could be the case that the land fell.
    True BuckWheat and we need to stay away from that sort of “evidence”. For instance, the Peak District, in the UK is a National Park. It was formed 325 million years ago from a tropical lagoon but is now in the middle of England!
    http://www.brixworth.demon.co.uk/peak.htm

  67. DaveF: I’m really a layman regarding this matter, but you asked an interesting question, so I searched and found this table:
    http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html
    And as you can see, you were right in your assumptions that very cold water will not expand as much as warmer water if the temperature increases with the same amount of degrees: The decrease in density for typical ocean water (35g/kg salt) is much smaller if the temperature rises from 0 to 5 degrees than if it rises from 20 to 25 degrees.

  68. Are they saying that the “Asymptoting Sea Level Rise” we have experienced for the past 15K years is likely to continue for the foreseeable future – through the 21st Century? That’s what I thought. Nice to know that there really are a lot more levelheaded “scientists” out there than Mann,PennState&Co. would have us believe. Universities really do deserve to be known by the faculty they keep. I think it’s too late to do anything for East Anglia.

  69. Espen: Many thanks for going to the trouble of getting that table for me. I’ve made a note of it and will look carefully at it. This site really does attract the best people! Dave.

  70. Observations v models (from the Australian CSIRO).
    <blockquote"Recent observations show the observed sea levels from tide gauges (blue) and satellites (red) are tracking near the upper bound (black line) of the IPCC 2001 projections (grey shading and black lines) since the start of the projections in 1990 (Rahmstorf et al. 2007). This upper limit leads to a global-averaged sea-level rise by 2100 of 88 cm compared to 1990 values. These observations do not necessarily indicate that sea level will continue to track this upper limit – it may diverge above or below this upper limit. However, the ice sheet uncertainties referred to above are essentially one-sided – i.e. they could lead to a significantly larger sea-level rise than current projections but are unlikely to lead to a significantly smaller rise."
    http://www.cmar.csiro.au/sealevel/sl_proj_obs_vs_proj.html
    Millennial and centennial time series from the same source:
    http://www.cmar.csiro.au/sealevel/sl_hist_few_hundred.html
    (In reference to recent comments here. e.g, Rahmstorf et al 2007 projections, in the IPCC 2001 assessment, were less than observations)

  71. DaveF says:
    August 10, 2010 at 10:49 am
    “Packbear: The UK and France may not have had the sea between them but I suspect there was a really big river to cross. The Rhine, aided and abetted by the Seine and the Thames, in summer, would have had to go somewhere.”
    The Rhine and Thames probably went North, to enter the Arctic Ocean alongside what is now Norway. The Seine probably went West, down what is now the English Channel. That would leave a dry landbridge between England and France across the Strait of Dover. I don’t know whether there’s any hard geological or archeological evidence for (or against) this. If anyone knows of any perhaps they could mention it?

  72. And the English can probably thank Joan of Arc for not becoming a department of France once The Kings’ English became Les Rois Français …

  73. Paul Birch: The Rhine couldn’t have gone north because the UK and the area which is now the top and middle of the North Sea had half a mile of ice on it. I believe there is still a current from the mouth of the Rhine that flows along the bottom of the English Channel. The Thames would have had to go south, too, but probably only flowed for few weeks in summer. Of course, you could have walked across the ice from Denmark, and I daresay hunters did so, but you’d have had to watch out for those nice, cuddly polar bears! Best wishes, Dave.

  74. DaveF says:
    August 11, 2010 at 10:32 am
    “The Rhine couldn’t have gone north because the UK and the area which is now the top and middle of the North Sea had half a mile of ice on it. I believe there is still a current from the mouth of the Rhine that flows along the bottom of the English Channel. The Thames would have had to go south, too, but probably only flowed for few weeks in summer. Of course, you could have walked across the ice from Denmark, and I daresay hunters did so, but you’d have had to watch out for those nice, cuddly polar bears! Best wishes, Dave.”
    I do see what you mean about the ice. However, I don’t see how there can be much of a bottom current from the Rhine to the English Channel now; there’s too much shallow water in the way. Ditto from the Thames. The undersea contours don’t look right (ridges across the way the rivers would have to flow). They were probably even less suitable back then, because the trough of relatively deep water in the middle of the Dover Strait was pretty obviously created by tidal scouring as the landbridge submerged. But both the Thames and the Rhine could have found a route East towards Denmark, then up to the Skagerrak, where a tongue of the Arctic Ocean forms a deep channel. Even when sea level was at its lowest, that would have provided a viable exit under the ice. The undersea contours do look about right for that (though I realise that they must have changed considerably since then).

  75. pouncer August 10, 2010 at 3:30 am:
    “I’m not in any way convinced the sea levels are prone to catastrophic rise… And in the absence of oceans overwhelming the current coast line — exactly what is bad about warming?”
    To pouncer and others. I recommend Mark Lynas “Six Degrees”. It is an informative, accessible, well researched read about what might reasonably be expected to occur should mean global temperature rise 1C, 2C, 3C, 4C… The author is a believer in AGW but does not predict any particular temperature increase (despite the “alarmist” sounding title). Chapters post 4C become progressively speculative as supporting data sets become sparser.
    My perception is that threats to agriculture will prove far more disruptive than sea level rise. From p96 in the “two degrees” chapter: “the two degree world will see escalating challenges as crop-producing areas struggle to adjust to a warming climate”. So, at only +2C, the world’s food producing capacity for our ever growing population will likely come under stress. Given that paleo studies indicate a doubling of CO2 will result in a 3C (+/-1C) rise I find this assessment very sobering.
    Beyond 2C the variety and magnitude of changes will pose potentially insurmountable problems, especially in many poorer parts of the world. Some will no doubt dismiss this post as misguided, alarmist propoganda driven by blinkered dogma. To those with a genuine interest in “what is the big deal if temperatures rise anyway?” please take the time to read “Six Degrees” and follow up on some of its research paper references.

  76. Here’s a speculative hypothesis: what if rising sea level reaching a certain level triggers the end of the interglacial? e.g. by causing a shift in ocean currents and upwelling? Is there any data on sea level at the terminations of other recent interglacials?

  77. it is an important result that the palaeo-sea-level data rule out such a response.
    It is an important sign of progress that a climate related study actually checks an AGW related hypothesis against palaeo data.
    How close are they to making the next logical step: palaeo climate data (e.g. temps, CO2) rules out CAGW?
    Ref – e.g. The current WUWT post on mesozoic period with similar climate to now but 10+ x more CO2

  78. The Sydney Morning Herald has run an article, 12/8/10, quoting scientists calcuate rises to exceed 7 meters!!!! and has an overalay of the ice-shelf over the state of NSW.
    The researcher/journo has obviously not got to these details as yet.
    check it out.
    macha (WA)

  79. Paul Birch: This is from Wikipedia. Article “The Rhine”, paragraph “Ice Ages”.
    “The last Ice Age……..(Last Glacial Maximum). During this time the lower Rhine flowed roughly west through the Netherlands and extended to the south-west, through the English Channel, and finally to the Atlantic Ocean.”
    Before the Ice Ages it flowed north, apparently, but I meant during the last Ice Age. Best wishes, Dave.

  80. DaveF says:
    August 12, 2010 at 2:31 am
    “This is from Wikipedia. Article “The Rhine”, paragraph “Ice Ages”.”
    Thanks for that. It has obviously been claimed that ice dammed up the Rhine’s northern exit to the Arctic, causing the Rhine to break out into the English Channel, but the claim doesn’t seem to hold water (!). In this glaciation, the westernmost part of Jutland was apparently ice free, or at the western edge of the Scandinavian ice sheet. “Doggerland” was apparently tundra, so there was a clear route for the Rhine to the deep water ocean channel. I find it hard to see how that exit could have been completely blocked. Even if an ice shelf extended over that channel (which the maps don’t show) that wouldn’t stop the river continuing to flow beneath it. Not even if the shelf became thick enough to ground; the river flow would still keep the channel open, or re-open it if an ice-fall somehow blocked it. The only evidence for the claim seems to be the scoured channel in the Strait of Dover – but tidal scouring could manage that quite effectively without any catastrophic flood. There are just such channels around the Isle of Wight. I remain to be convinced.

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